Adult Drug Courts - Evidence Indicates Recidivism Reductions, GAO, 2005

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Adult Drug Courts - Evidence Indicates Recidivism Reductions, GAO, 2005

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United States Government Accountability Office

GAO

Report to Congressional Committees

February 2005

ADULT DRUG
COURTS
Evidence Indicates
Recidivism
Reductions and Mixed
Results for Other
Outcomes

GAO-05-219

February 2005

ADULT DRUG COURTS
Accountability Integrity Reliability

Highlights
Highlights of GAO-05-219, a report to
congressional committees

Evidence Indicates Recidivism
Reductions and Mixed Results for Other
Outcomes

Why GAO Did This Study

What GAO Found

Drug court programs, which were
established in the late 1980s as a
local response to increasing
numbers of drug-related cases and
expanding jail and prison
populations, have become popular
nationwide in the criminal justice
system. These programs are
designed to reduce defendants’
repeated crime (that is, recidivism),
and substance abuse behavior by
engaging them in a judicially
monitored substance abuse
treatment. However, determining
whether drug court programs are
effective at reducing recidivism and
substance use has been challenging
because of a large amount of weak
empirical evidence.

Most of the adult drug court programs assessed in the evaluations GAO
reviewed led to recidivism reductions during periods of time that generally
corresponded to the length of the drug court program. GAO’s analysis of
evaluations reporting these data for 23 programs showed the following:
•
Lower percentages of drug court program participants than comparison
group members were rearrested or reconvicted.
•
Program participants had fewer recidivism events than comparison
group members.
•
Recidivism reductions occurred for participants who had committed
different types of offenses.
•
There was inconclusive evidence that specific drug court components,
such as the behavior of the judge or the amount of treatment received,
affected participants’ recidivism while in the program.
Recidivism reductions also occurred for some period of time after
participants completed the drug court program in most of the programs
reporting these data.

The 21st Century Department of
Justice Appropriations
Authorization Act requires that
GAO assess drug court program
effectiveness. To meet this
mandate, GAO conducted a
systematic review of drug court
program research, from which it
selected 27 evaluations of 39 adult
drug court programs that met its
criteria for, among other things,
methodological soundness. This
report describes the results of that
review of published evaluations of
adult drug court programs,
particularly relating to (1)
recidivism outcomes, (2) substance
use relapse, (3) program
completion, and (4) the costs and
benefits of drug court programs.
DOJ reviewed a draft of this report
and had no comments. Office of
National Drug Control Policy
reviewed a draft of this report and
generally agreed with the findings.

Evidence about the effectiveness of adult drug court programs in reducing
participants’ substance use relapse is limited to data available from eight
drug court programs. Evaluations of these eight drug court programs
reported mixed results on substance use relapse. For example, drug test
results generally showed significant reductions in use during participation in
the program, while self-reported results generally showed no significant
reductions in use.
Completion rates, which refer to the percentage of individuals who
successfully completed a program, in selected adult drug court programs
ranged from 27 to 66 percent. Other than participants’ compliance with drug
court program procedures, no other program factor (such as the severity of
the sanction that would be invoked if participants failed to complete the
program) consistently predicted participants’ program completion.
A limited number of evaluations—four evaluations of seven adult drug court
programs—provided sufficient cost and benefit data to estimate their net
benefits. Although the cost of six of these programs was greater than the
costs to provide criminal justice services to the comparison group, all seven
programs yielded positive net benefits, primarily from reductions in
recidivism affecting judicial system costs and avoided costs to potential
victims. Financial cost savings for the criminal justice system (taking into
account recidivism reductions) were found in two of the seven programs.
Figure 1: Overview of GAO Analysis of Drug Court Program Effectiveness
Drug
offenders

www.gao.gov/cgi-bin/getrpt?GAO-05-219.
To view the full product, including the scope
and methodology, click on the link above.
For more information, contact Laurie E.
Ekstrand at (202) 512-8777 or
ekstrandl@gao.gov.

Justice system

Drug court
program efforts
to reduce
recidivism

Program evaluations
(27 evaluated)
Enter
program

- Judicial
supervision
- Drug treatment
- Monitoring

End of
program

Recidivism
Drug use
Program completion
Costs of the program

Findings
- Reduced recidivism while in program
- Evidence on drug use outcomes
limited because of few studies
- Compliance related to completion
- Can have positive financial benefits

Source: GAO review of drug court program evaluations.

United States Government Accountability Office

Contents

Letter

1
Background
Results
Concluding Observations
Agency Comments and Our Evaluation

3
5
7
8

Appendix I

Objectives, Scope, and Methodology

Appendix II

Evaluations Used Multiple Approaches to Assess
Selection Bias
Comparison Groups Can Introduce the Problem of Selection Bias
Evaluations Addressed Selection Bias through Design
Evaluations Used a Variety of Statistical Methods to Minimize the
Possible Effects of Selection Bias

Appendix III

25
27
32

Overview of Drug Court Program Characteristics and
Participants
36
Drug Court Program Components
Drug Court Program Participants

Appendix V

16
17

GAO Criteria for Assessing Evaluations of Drug Court
Programs’ Cost-Benefit Analyses
25
The Evaluations We Reviewed and the Net Benefit Measure
Criteria for Assessing a Drug Court Program’s Cost-Benefit
Analysis
How the Drug Court Evaluations We Reviewed Used the Identified
Cost-Benefit Principles

Appendix IV

36
40

Drug Court Programs Are Associated with Recidivism
Reductions
44
Drug Court Programs Led to Within-Program Recidivism
Reductions
Limited Evidence Indicates That Recidivism Reductions Endure

Page i

44
52

GAO-05-219 Drug Court Effectiveness

Appendix VI

Appendix VII

Limited and Mixed Evidence on Drug Court Programs’
Impacts on Substance Use Relapse
57
Limited Evidence on Drug Court Programs’ Impact on Substance
Use Relapse
Evidence on Drug Court Programs’ Impact on Substance Use
Relapse Is Mixed

Evidence Is Mixed about the Factors That Predict
Program Completion

Program Completion Rates Vary
Program Completion Is Associated with Compliance with Program
Procedures
Effects of Drug Court Programs’ Components on Program
Completion Are Mixed
Participants Who Were Older and Had Less Criminal History than
Other Participants Were Most Likely to Complete Programs

Appendix VIII

Appendix IX

62
64
66
69

Evidence from Four Evaluations Indicates Drug Court
Programs’ Positive Net Benefits
71
Most Evaluations Found Drug Court Programs More Expensive
than Conventional Case Processing
Drug Court Programs’ Net Benefits Derived from Reductions in
Recidivism
All Seven Drug Court Programs Reported Positive Net Benefits
Net Benefits May Underestimate the Programs’ True Benefits

72
73
74

GAO Contacts and Staff Acknowledgments

GAO Contacts
Acknowledgments

75
75

Bibliography

Tables
Table 1: Summary Information about Adult Drug Court Programs
Included in GAO’s Review
Table 2: The Eight Drug Court Program Evaluations in Our CostBenefit Review

Page ii

11
14

GAO-05-219 Drug Court Effectiveness

Table 3: Research Designs, Comparison Groups, and Methods to
Address Selection Bias for Evaluations GAO Used in
Recidivism Analysis
Table 4: The Eight Drug Court Program Evaluations in Our CostBenefit Review
Table 5: Five Criteria for Assessing a Cost-Benefit Analysis of a
Drug Court Program
Table 6: Summary of Criteria Applied in Eight Drug Court Program
Evaluation Assessments
Table 7: Differences in Overall Rearrest Rates between Drug Court
Program Participants and Comparison Group Members
Table 8: Differences in Reconviction Rates between Drug Court
Program Participants and Comparison Group Members
Table 9: Differences in Rearrest and Reconviction Rates, over
Longer Time Periods, between Drug Court Program
Participants and Comparison Group Members
Table 10: Post-Program Differences in Recidivism in Six New York
State Drug Court Programs
Table 11: Substance Use Relapse Results, by Different Measures of
Use, for Programs GAO Reviewed
Table 12: Completion Rates for Selected Drug Court Programs
Included in GAO’s Review
Table 13: Reported Costs per Drug Court Program Participant in
Four Evaluations
Table 14: Net Benefits per Participant in Seven Drug Court
Programs

21
26
27
33
46
48

53
55
58
63
72
74

Abbreviations
APD
GAO
ONDCP

antisocial personality disorder
Government Accountability Office
Office of National Drug Control Policy

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Page iii

GAO-05-219 Drug Court Effectiveness

United States Government Accountability Office
Washington, DC 20548

February 28, 2005
The Honorable Arlen Specter
Chairman
The Honorable Patrick J. Leahy
Ranking Minority Member
Committee on the Judiciary
United States Senate
The Honorable F. James Sensenbrenner, Jr.
Chairman
The Honorable John Conyers, Jr.
Ranking Minority Member
Committee on the Judiciary
House of Representatives
Drug court programs were established in the late 1980s as a local response
to increasing numbers of drug-related cases and expanding jail and prison
populations. These programs are designed to use a court’s authority to
reduce crime by changing defendants’ substance abuse behavior. Under
this concept, in exchange for the possibility of dismissed charges or
reduced sentences, defendants are diverted to drug court programs in
which they agree to participate in judicially monitored substance abuse
treatment. Title II of the 21st Century Department of Justice
Appropriations Authorization Act reauthorizes the award of federal grants
for drug court programs that include court-supervised drug treatment.1
The award of federal grants to drug court programs was first authorized
under Title V of the Violent Crime Control and Law Enforcement Act of
1994.2
Drug court programs have become popular nationwide in the criminal
justice system. As of September 2004, there were over 1,200 drug court
programs operating in addition to about 500 being planned. With such
expansion, it is important for policy and operational decision makers to
have definitive information about drug court programs’ effectiveness in

Pub. L. No. 107-273, 116 Stat. 1758, 1795 (2002).

Pub. L. No. 103-322.

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GAO-05-219 Drug Court Effectiveness

reducing recidivism and substance use relapse.3 In this respect, the 21st
Century Department of Justice Appropriations Authorization Act requires
that we study drug court program effectiveness.4 In response, this report
describes the results of published empirical evaluations of adult drug
court programs, particularly relating to (1) recidivism outcomes of
participants and other comparable offenders, (2) substance use relapse of
participants and other comparable offenders, (3) program completion of
participants, and (4) costs and benefits of drug court programs.
To address our objectives, we conducted a systematic review of drug court
program literature. We identified 117 evaluations of adult drug court
programs in the United States that were published between May 1997 and
January 2004 and reported recidivism, substance use relapse, or program
completion outcomes. Of these 117, we selected 27 evaluations that met
additional criteria for methodological soundness. Most of the evaluations
we selected used designs in which all drug court program participants
were compared with an appropriate group of similar offenders who did
not participate in the drug court program. In order to ensure that the
groups are similar in virtually all respects aside from the intervention, we
selected evaluations in which the comparison group was matched to the
program group as closely as possible on a number of characteristics or
that used statistical models to adjust, or control for, preexisting
differences between the program and comparison groups. Five of the
27 evaluations were experiments in which participants were randomly
assigned to groups. Random assignment works to ensure that the groups
are comparable.
The 27 evaluations we selected for our review reported information on
39 unique adult drug court programs. We systematically collected
information from these evaluations about the methodological
characteristics of the evaluations, the participants and components of the
drug court programs, the outcomes, and, where available, the costs of the
drug court programs. To assess the methodological strength of the
evaluations, we used generally accepted social science principles.
Additionally, we used standard cost-benefit criteria to screen and assess
the eight evaluations that reported cost and benefit information. Four of
these contained sufficient data on costs and benefits to allow us to assess

We use the term recidivism to refer generally to the act of committing new criminal
offenses after having been arrested or convicted of a crime.

Pub. L. No. 107-273, 116 Stat. 1758, 1799 (2002).

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GAO-05-219 Drug Court Effectiveness

net benefits. We selected the evaluations in our review according to the
strength of their methodologies; therefore, our results cannot be
generalized to all drug court programs or their evaluations. Finally, we
interviewed drug court researchers and officials at the Department of
Justice, the National Institute on Drug Abuse, and the Office of National
Drug Control Policy (ONDCP). We conducted our work from October 2003
through February 2005 in accordance with generally accepted government
auditing standards. Appendix I presents more details about our scope and
methodology, including a list of the evaluations we reviewed. Appendix II
describes the research designs and methods used in assessing recidivism
in the evaluations we reviewed, and appendix III presents our criteria for
assessing evaluations of drug court programs’ cost-benefit analyses.

Background

Of the 1,700 drug court programs operating or planned as of September
2004, about 1,040—nearly 770 operating and about 270 being planned—
were adult drug court programs, according to data collected by the Office
of Justice Programs’ Drug Court Clearinghouse and Technical Assistance
Project.5 The primary purpose of these programs is to use a court’s
authority to reduce crime by changing defendants’ substance abuse
behavior. In exchange for the possibility of dismissed charges or reduced
sentences, eligible defendants who agree to participate are diverted to
drug court programs in various ways and at various stages in the judicial
process. These programs are typically offered to defendants as an
alternative to probation or short-term incarceration.
Drug court programs share several general characteristics but vary in their
specific policies and procedures because of, among other things,
differences in local jurisdictions and criminal justice system practices. In
general, judges preside over drug court proceedings, which are called
status hearings; monitor defendants’ progress with mandatory drug
testing; and prescribe sanctions and rewards as appropriate in
collaboration with prosecutors, defense attorneys, treatment providers,
and others. Drug court programs also vary in terms of the substance abuse
treatment required. However, most programs offer a range of treatment
options and generally require a minimum of about 1 year of participation
before a defendant completes the program.

The totals of adult drug court programs include tribal drug court programs, but exclude
family drug court programs.

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GAO-05-219 Drug Court Effectiveness

In order to determine defendants’ eligibility for participation, drug court
programs typically screen defendants based on their legal status and
substance use. The screening process and eligibility criteria can vary
across drug court programs.6 According to the literature, eligible drug
court program participants ranged from nonviolent offenders charged with
drug-related offenses who have substance addictions to relatively mediumrisk defendants with fairly extensive criminal histories and failed prior
substance abuse treatment experiences. Participants were also described
as predominantly male with poor employment and educational
achievements. Appendix IV presents additional information about the
general characteristics of drug court programs and participants in the
evaluations we reviewed.
Research on drug court programs has generally focused on program
descriptions and process measures, such as program completion rates,
and presented limited empirical evidence about the effectiveness of drug
court programs in reducing recidivism and substance use. In 1997, we
reported on 12 evaluations that met minimum research standards and
concluded that the evaluations showed some positive results but did not
firmly establish whether drug court programs were successful in reducing
offender recidivism and substance use relapse.7 More recently, two
syntheses of multiple drug court program evaluations have drawn positive
conclusions about the impact of drug court programs. One synthesis
concluded that criminal activity and substance use are reduced relative to
other comparable offenders while participants are engaged in the drug
court program, and that program completion rates ranged from 36 to
60 percent.8 Further, the other synthesis reported that drug offenders
participating in a drug court program are less likely to re-offend than

Criteria for legal eligibility can include the current offense, criminal justice histories, or
supervision status (that is, whether the defendant is currently on probation). Criteria
related to substance use can include frequency and type of current substance use, prior
treatment experiences, or motivation to seek substance abuse treatment.
7

GAO, Drug Courts: Overview of Growth, Characteristics, and Results, GAO/GGD-97-106
(Washington, D.C.: July 31, 1997).
8

Belenko, S. Research on Drug Courts: A Critical Review 2001 Update. The National
Center on Addiction and Substance Abuse at Columbia University, June 2001, p. 1. In his
review, Belenko states that the reported program completion rates are consistent with
findings in other studies.

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GAO-05-219 Drug Court Effectiveness

similar offenders sentenced to traditional correctional options, such as
probation.9
Some of the evaluations included in these two syntheses had
methodological limitations such as, the lack of strong comparison groups
and the lack of appropriate statistical controls. Some did not use designs
that compared all drug court program participants—including graduates,
those still active, and dropouts—with similar nonparticipants. For
example, they compared the outcomes of participants who completed the
program with the outcomes of those who did not (that is, dropouts). These
evaluations, upon finding that program graduates had better outcomes
than dropouts, have concluded that drug court programs are effective.
This is a likely overestimation of the positive effects of the intervention
because the evaluation is comparing successes to failures, rather than all
participants to nonparticipants. Additionally, other evaluations did not use
appropriate statistical methods to adjust for preexisting differences
between the program and comparison groups. Without these adjustments,
variations in measured outcomes for each group may be a function of the
preexisting differences between the groups, rather than the drug court
program.

Results

In most of the evaluations we reviewed, adult drug court programs led to
recidivism reductions during periods of time that generally corresponded
to the length of the drug court program—that is, within-program.10 Our
analysis of evaluations reporting recidivism data for 23 programs showed
that lower percentages of drug court program participants than
comparison group members were rearrested or reconvicted. Program
participants also had fewer incidents of rearrests or reconvictions and a
longer time until rearrest or reconviction than comparison group
members. These recidivism reductions were observed for any felony
offense and for drug offenses, whether they were felonies or
misdemeanors. However, we were unable to find conclusive evidence that
specific drug court program components, such as the behavior of the
judge, the amount of treatment received, the level of supervision provided,
and the sanctions for not complying with program requirements, affect

Wilson, D.B., O. Mitchell, and D.L. MacKenzie, A Systematic Review of Drug Court Effects
on Recidivism, (forthcoming), p. 20.

We use within-program to refer to the period of time that all individuals who are enrolled
are expected to be participating in the drug court program.

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GAO-05-219 Drug Court Effectiveness

participants’ within-program recidivism. Post-program recidivism
reductions were measured for up to 1 year after participants completed
the drug court program in several evaluations, and in these the evidence
suggests that the recidivism differences observed during the program
endured. A more detailed description of the recidivism reduction results is
included in appendix V.
Evidence about the effectiveness of drug court programs in reducing
participants’ substance use relapse is limited and mixed. The evidence
included in our review on substance use relapse outcomes is limited to
data available from eight drug court programs. The data include drug test
results and self-reported drug use; both measures were reported for some
programs. Drug test results generally showed significant reductions in use
during participation in the program, while self-reported results generally
showed no significant reductions in use. Appendix VI presents additional
information about the evaluations we reviewed that reported on substance
use relapse outcomes.
Completion rates, which refer to the number of individuals who
successfully completed a drug court program as a percentage of the total
number admitted, in the programs we reviewed that assessed completion
ranged from 27 to 66 percent. As might be expected, program completion
was associated with participants’ compliance with program requirements.
Specifically, evaluations of 16 adult drug court programs that assessed
completion found that participants’ compliance with procedures was
consistently associated with completion. These program procedures
include attending treatment sessions, engaging in treatment early in the
program, and appearing at status hearings. No other program factor, such
as the severity of the sanction that would be invoked if participants failed
to complete the program and the manner in which judges conducted status
hearings, predicted participants’ program completion. Several
characteristics of the drug court program participants themselves were
also associated with an increased likelihood of program completion. These
characteristics include lower levels of prior involvement in the criminal
justice system and age, as older participants were more likely to complete
drug court programs than younger ones. Appendix VII presents additional
information about the evaluations we reviewed that reported on program
completion.
A limited number of evaluations in our review discussed the costs and
benefits of adult drug court programs. Four evaluations of seven drug
court programs provided sufficient cost and benefit data to estimate their
net benefits (that is, the benefits minus costs). The cost per drug court

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GAO-05-219 Drug Court Effectiveness

program participant was greater than the cost per comparison group
member in six of these drug court programs. However, all seven programs
yielded positive net benefits, primarily from reductions in recidivism
affecting both judicial system costs and avoided costs to potential victims.
Net benefits ranged from about $1,000 per participant to about $15,000 in
the seven programs. These benefits may underestimate drug court
programs’ true benefits because the evaluations did not include indirect
benefits (such as reduced medical costs of treated participants). Financial
cost savings for the criminal justice system (taking into account recidivism
reductions) were found in two of the seven programs. We provide
additional information about the reported costs and benefits of drug court
programs we reviewed in appendix VIII.

Concluding
Observations

Overall, positive findings from relatively rigorous evaluations in relation to
recidivism, coupled with positive net benefit results, albeit from fewer
studies, indicate that drug court programs can be an effective means to
deal with some offenders. These programs appear to provide an
opportunity for some individuals to take advantage of a structured
program to help them reduce their criminal involvement and their
substance abuse problems, as well as potentially provide a benefit to
society in general.
Although not representative of all drug court programs, our review of
27 relatively rigorous evaluations provides evidence that drug court
programs can reduce recidivism compared to criminal justice alternatives,
such as probation. These results are consistent with those of past reviews
of drug court evaluations. Positive results concerning recidivism are
closely associated with program completion. Specifically, while drug court
participation is generally associated with lower recidivism, the recidivism
of program completers is lower than for participants in comparison or
control groups. Thus, practices that encourage program completion may
enhance the success of drug court programs in relation to recidivism.
While our review sheds little light on the specific aspects of these
programs that are linked to positive recidivism outcomes, both participant
compliance with drug court procedures and some participant
characteristics seem to be related to success. To the extent that research
can help to discern best practices for drug courts, the models for effective
programs can be enhanced. Specifically, to the extent that drug court
program managers can learn more about methods to retain participants for
the duration of the program, they may be able to further enhance the
positive impacts of drug court programs.

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GAO-05-219 Drug Court Effectiveness

Agency Comments
and Our Evaluation

We requested comments on a draft of this report from the Attorney
General and the Director of ONDCP. Department of Justice officials
informed us that the agency had no comments on the report. ONDCP
officials informed us that the agency generally concurred with our
findings.

We are sending copies of this report to other interested congressional
committees, the Attorney General, and the Director of the Office of
National Drug Control Policy. We will also make copies available to others
upon request. In addition, the report will be available at no charge on
GAO’s Web site at http://www.gao.gov.
If you or your staff have any questions concerning this report, please
contact me at (202) 512-8777 or by e-mail at EkstrandL@gao.gov or
William J. Sabol, Assistant Director, at (202) 512-3464, or SabolW@gao.gov.
Key contributors to this report are listed in appendix IX.

Laurie E. Ekstrand, Director
Homeland Security and Justice Issues

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GAO-05-219 Drug Court Effectiveness

Appendix I: Objectives, Scope, and
Methodology

Appendix I: Objectives, Scope, and
Methodology
The 21st Century Department of Justice Appropriations Authorization Act
requires that we assess drug court program effectiveness.1 Our objectives
were to assess the results of methodologically sound, published empirical
evaluations of adult drug court programs, particularly relating to
(1) recidivism outcomes of participants and other comparable offenders,
(2) substance use relapse of participants and other comparable offenders,
(3) program completion of participants, and (4) costs and benefits of drug
court programs.
To identify the universe of evaluations to include in our review, we used a
three-stage process. First, we (1) conducted key-word searches of criminal
justice and social science research databases;2 (2) searched drug court
program-related Web sites, such as those of the National Drug Court
Institute and the National Association of Drug Court Professionals;
(3) reviewed bibliographies, published summaries, meta-analyses, and
prior GAO reports on drug court programs;3 and (4) asked drug court
researchers and officials in agencies that fund drug court research to
identify evaluations. Our literary search identified over 230 documents,
which consisted of published and unpublished outcome evaluations,
process evaluations that described program objectives and operations,
manuals and guides related to drug court program operations,
commentary from drug court practitioners, and summaries of multiple
program evaluations. Next, we reviewed these documents and identified
117 evaluations of adult drug court programs in the United States that
(1) were published between May 1997 and January 20044 and (2) reported
recidivism, substance use relapse, or program completion outcomes.
Finally, to select the evaluations we used in our in-depth review, we
screened them to determine whether they met additional criteria for

Pub. L. No. 107-273, 116 Stat. 1758, 1799 (2002).

We searched the ERIC, Biosis Previews, Social Scisearch, National Criminal Justice
Reference Service, Dissertation Abstracts Online, Gale Group Magazine Database, Wilson
Social Science Abstracts, Gale Group Trade & Industry Database, Gale Group Health &
Wellness Database, Gale Group Legal Resources Index, and Periodicals Abstracts PlusText.
3

GAO, Drug Courts: Information on a New Approach to Address Drug-Related Crime,
GAO/GGD-95-159BR (Washington, D.C.: May 22, 1995); GAO, Drug Courts: Overview of
Growth, Characteristics, and Results, GAO/GGD-97-106 (Washington, D.C.: July 31, 1997);
and GAO, Drug Courts: Better DOJ Data Collection and Evaluation Efforts Needed to
Measure Impact of Drug Court Programs, GAO-02-434 (Washington, D.C.: April 18, 2002).
4

In our last report that assessed the published research, GAO/GGD-97-106, we completed
our review in May 1997.

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GAO-05-219 Drug Court Effectiveness

Appendix I: Objectives, Scope, and
Methodology

methodological soundness. Specifically, to assess recidivism and
substance use relapse, we selected evaluations that used either an
experimental design in which (1) eligible offenders were randomly
assigned to different programs or conditions and (2) there was an
acceptable level of attrition5 or a quasi-experimental design in which (1) all
drug court program participants were compared with an appropriate
group of comparable offenders who did not participate in the drug court
program, and (2) appropriate statistical methods were used to adjust, or
control, for group differences. If random assignment was not used, in an
attempt to ensure that the groups were similar, aside from program
participation (the intervention), the comparison group(s) should have
been as alike as possible on a range of important characteristics.
Statistical analyses can be used to further minimize differences between
the program and comparison groups. Typically, statistical analyses to
control for differences such as these are not necessary when study
participants are randomly assigned to groups.
To assess program completion, we also selected evaluations that
compared the outcomes of participants (such as program graduates and
those who dropped out) within a drug court program in order to determine
what factors, if any, are associated with program completion. We selected
those evaluations that used appropriate statistical methods to control for
differences between the participant groups. Of the 117 evaluations we
screened, we selected 27 evaluations for our in-depth review.
The 27 evaluations we selected for our review reported information on
39 unique adult drug court programs that were implemented between 1991
and 1999. Table 1 lists the drug court program evaluated, researchers, and
outcomes we used in our assessment of drug court program effectiveness.
All of the evaluations we reviewed, as well as others consulted, is included
in the bibliography.

Over time, participants in an evaluation can drop out for various reasons. Acceptable
levels of attrition can vary depending on other characteristics of the evaluation design,
such as the sample size, the time frames covered, and statistical methods used.

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GAO-05-219 Drug Court Effectiveness

Appendix I: Objectives, Scope, and
Methodology

Table 1: Summary Information about Adult Drug Court Programs Included in GAO’s Review
Outcomes used in our assessment
Drug court program evaluated (researcher)

Recidivism

Drug use

Bakersfield (Calif.) Municipal Drug Court
(Anspach and Ferguson, 2003)

Program
completion
Yes

Baltimore City (Md.) Drug Treatment Court
(Banks and Gottfredson, 2003)

Yes

(Gottfredson and Exum, 2002; Gottfredson, Najaka, and
Kearley, 2003)

Yes

Breaking the Cycle Program, Tacoma, Wash
(Harrell and others, 2003)

Yes

Bronx (N.Y.) Treatment Court
(Rempel and others, 2003)

Yes

Breaking the Cycle Program, Birmingham, Ala.
(Harrell and others, 2003)
Breaking the Cycle Program, Jacksonville, Fla.
(Harrell and others, 2003)

Yes

Brooklyn (N.Y.) Treatment Court
(Rempel and DeStefano, 2001)

Yes

(Rempel and others, 2003)

Yes

Broward County (Fla.) Drug Court
(Schiff and Terry, 1997)

Yes

(Senjo and Leip, 2001)

Yes

Chester County (Penn.) Drug Court Program
(Brewster, 2001)

Yes

Clark County Drug Court (Las Vegas, Nev.)
(Goldkamp, White, and Robinson, 2001)

Yes

(Miethe, Lu, and Reese, 2000)

Yes

Creek County (Okla.) Drug Court
(Anspach and Ferguson, 2003)

Yes

D.C. Superior Court Drug Intervention Program
(Harrell, Cavanagh, and Roman, 1998)

Yes

Douglas County (Neb.) Drug Court
(Spohn and others, 2001; Martin, Spohn, Piper, and
Frenzel-Davis, 2001)

Yes

Escambia County (Fla.) Drug Court
(Peters and Murrin, 2000)

Yes

(Peters, Haas, and Murrin, 1999)

Yes

(Truitt and others, 2002)

Yes

Page 11

Yes

GAO-05-219 Drug Court Effectiveness

Appendix I: Objectives, Scope, and
Methodology

Outcomes used in our assessment
Drug court program evaluated (researcher)

Recidivism

Hamilton County Drug Court (Cincinnati, Ohio)
(Listwan and others, 2003)

Yes

Drug use

Program
completion

Jackson County (Mo.) Drug Court
(Anspach and Ferguson, 2003)

Yes

(Truitt and others, 2002)

Yes
c

Kentucky Drug Court Programs
(Logan, Hoyt, and Leukefeld, 2001)

Yes

Las Cruces (N. Mex.) Municipal DWI Drug Court
(Breckenridge and others, 2000)

Yes

Los Angeles County (Calif.) Drug Court Program
(Deschenes and others, 1999; Fielding and others, 2002)

Yes

Maricopa County (Ariz.) First Time Drug Offender Program
(Deschenes, and others, 1996; Turner and others, 1999)

Yes

Multnomah County (Ore.) Sanctions, Treatment, Opportunity,
and Progress (STOP) Drug Diversion Program
(Finigan, 1998)

Yes

(Goldkamp, White, and Robinson, 2001)

Yes

New Castle County (Del.) Drug Court
(Marlowe and others, 2004; Festinger and others, 2002)
North Carolina Drug Treatment Court
(Craddock, 2002)

Yes

Okaloosa County (Fla.) Drug Court
(Peters and Murrin, 2000)

Yes

Orange County (Calif.) Drug Court Program
(Deschenes and others, 2001)

Yes

Queens (N.Y.) Treatment Court
(Rempel and others, 2003)

Yes

Rochester (N.Y.) Drug Treatment Court
(Rempel and others, 2003)

Yes

So. San Mateo County (Calif.) Drug Court
(Wolfe, Guydish, and Termondt, 2002)

Yes

St. Mary Parish (La.) Drug Court
(Anspach and Ferguson, 2003)

Yes

Suffolk County (N.Y.) Drug Treatment Court
(Rempel and others, 2003)

Yes

Syracuse (N.Y.) Community Treatment Court
(Rempel and others, 2003)

Yes

Washington State Drug Court Program
(Barnoski and Aos, 2003)

Yes
Source: GAO analysis of drug court program evaluations.

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Appendix I: Objectives, Scope, and
Methodology

a
According to the principal researcher of the evaluation, the Breaking the Cycle program is technically
not considered to be a drug court program. However, we included the program in our review because
it incorporates several of the basic drug court program components, such as drug testing and access
to treatment services.
b
Recidivism results for the Hamilton County evaluation were not included in our review because upon
our further review, we found that the nonequivalent control group design did not sufficiently control for
group differences that could have explained the reported (favorable) recidivism differences.
c

The evaluation of the Kentucky Drug Court Program included three programs: (1) Fayette Drug Court
program, (2) Jefferson County Drug Court program, and (3) Warren Drug Court program. The data for
these three programs were combined in the analyses conducted. However, information about the
program components and participants was reported separately for each program.

d
We included the evaluation of the Las Cruces Municipal DWI Drug Court because it was an
experiment that assessed recidivism. However, we did not include its results in our final review of
recidivism outcomes because it is a specialty court that handles only misdemeanor driving while
intoxicated (DWI) defendants.
e
The evaluation of Washington State Drug Court Program included six programs: those in (1) King,
(2) Kitsap, (3) Pierce, (4) Skagit, (5) Spokane, and (6) Thurston counties. Limited information about
the program components and participants were reported for each of the six programs. However,
some of the recidivism analyses combined data from multiple counties.

To obtain information on our outcomes of interest—that is, recidivism,
substance use relapse, and program completion—we used a data
collection instrument to systematically collect information about the
methodological characteristics of the evaluations, the participants and
components of the drug court programs, and the outcomes of the
participants and other comparable groups.
To assess the methodological strength of the 27 evaluations, we used
generally accepted social science principles.6 For example, we assessed
elements such as whether data were collected during or after program
completion and the appropriateness of outcome measures, statistical
analyses, and any reported results. Each evaluation was read and coded by
a senior social scientist with training and experience in evaluation
research methods. A second senior social scientist and other members of
our evaluation team then reviewed each completed data collection
instrument to verify the accuracy of the information included. Part of our
assessment also focused on the quality of the data used in the evaluations
as reported by the researchers and our observations of any problems with
missing data, any limitations of data sources for the purposes for which

Social science research standards are discussed in the scientific literature. For example,
see Campbell, Donald T., and Julian Stanley, Experimental and Quasi-Experimental
Designs for Research (Chicago: Rand McNally, 1963); Cook, Thomas D., and Donald T.
Campbell, Quasi-experimentation: Design and Analysis Issues for Field Settings
(Boston: Houghton Mifflin, 1990); and GAO, Designing Evaluations, GAO/PEMD-10.1.4
(Washington, D.C.: May 1991).

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GAO-05-219 Drug Court Effectiveness

Appendix I: Objectives, Scope, and
Methodology

they were used, and inconsistencies in reporting data; we incorporated
any data problems noted into our appraisals.
To assess the cost-benefit analyses of drug court program evaluations, we
reviewed all of the evaluations selected for our structured review that
reported cost or benefit information. Of the 27 evaluations included in our
in-depth review, 8 reported information about program costs and 4 about
benefits. The 8 evaluations we included in our cost review are shown in
table 2.
Table 2: The Eight Drug Court Program Evaluations in Our Cost-Benefit Review
Reported data on
Drug court program evaluation

Benefits

Costs

Breaking the Cycle Program
(Harrell and others, 2003)

Yes

D.C. Superior Court Drug Intervention Program
Harrell, Cavanagh, and Roman, 1998)

Yes

Multnomah County (Ore.) STOP Drug Diversion
Program (Carey and Finigan, 2003)

Yes

Washington State Drug Court Program
(Barnoski and Aos, 2003)

Yes

Douglas County (Neb.) Drug Court
(Martin, Spohn, Piper, and Frenzel-Davis, 2001)

Yes

Kentucky Drug Court Programs
(Logan, Hoyt, and Leukefeld, 2001)

Yes

Los Angeles County (Calif.) Drug Court Program
(Deschenes and others, 1999)

Yes

Maricopa County (Ariz.) First Time Drug Offender
Program (Deschenes and others, 1996)

Yes

Included in cost-benefit analysis

Not included in cost-benefit analysis

Source: GAO analysis of drug court program evaluations.

Four of the 8 evaluations reported sufficient data on both benefits and
costs, which allowed us to assess the reported net benefits of the drug
court programs. Specifically, we were able to determine whether the
reduction of recidivism—the benefit—would outweigh the additional costs
of a program. We used standard cost-benefit criteria to screen and assess
these evaluations that reported cost and benefit information. Additionally,
we reviewed methodologies describing approaches for conducting cost
analyses of drug court programs.

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Appendix I: Objectives, Scope, and
Methodology

We selected the evaluations in our review based on their methodological
strength; therefore, our results cannot be generalized to all drug court
programs or their evaluations. Although the findings of the evaluations we
reviewed are not representative of the findings of all evaluations of drug
court programs, the evaluations consist of those published evaluations we
could identify that used the strongest designs to assess drug court
program effectiveness.
Finally, we interviewed drug court program researchers and officials at the
Department of Justice, the National Institute on Drug Abuse, and the
Office of National Drug Control Policy. We conducted our work from
October 2003 through February 2005 in accordance with generally
accepted government auditing standards.

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GAO-05-219 Drug Court Effectiveness

Appendix II: Evaluations Used Multiple
Approaches to Assess Selection Bias

Appendix II: Evaluations Used Multiple
Approaches to Assess Selection Bias
Most of the evaluations included in our review used quasi-experimental
comparison groups.1 The use of quasi-experimental comparison groups
can result in comparisons between drug court participants and
comparison group members that differ on key variables related to
recidivism. Systematic difference between comparison groups and
treatment groups, called selection bias, threatens the validity of evaluation
findings. Though design and analysis strategies differed, each of the quasiexperimental evaluations in our review used some combination of design
and statistical methods to address the issue of selection bias. Approaches
to address selection bias in design generally included attempts to choose
comparison groups that share key commonalities with treatment groups
(usually including likelihood of eligibility to participate in a drug court
were it available) and therefore were less likely to differ on observed and
unobserved characteristics related to recidivism. The evaluations in our
review also included attempts to minimize the effects of selection bias
through the application of various statistical methods.

Comparison Groups
Can Introduce the
Problem of Selection
Bias

The observed differences in recidivism that we discuss in this report could
arise from measured and unmeasured sources of variation between drug
court participants and comparison group members. If comparison group
members differed systematically from drug court participants on variables
or factors that are also associated with recidivism and these variables
were not accounted for by the design or analysis used in the evaluation,
then the observed differences in recidivism could be due to these sources
of variation rather than participation in the drug court program. For
example, if successful drug court participants differed systematically in
their substance abuse addiction problems from the members of the group
against which they are compared, and if the differences in substance abuse
addiction are not explicitly assessed in the evaluation, these differences,
and not necessarily participation in the drug court program, could explain
any observed recidivism differences. Similarly, if participants differed
from comparison group members in their motivation to complete the drug
court, recidivism differences could arise from these. Evaluations generally
do not have measures of variables, such as motivation, that can be
explicitly included in the analysis of drug court outcomes.

In contrast to experimental control groups, where participants are deliberately randomly
assigned to either treatment or control groups for purposes of comparison, the comparison
groups in quasi-experimental groups are constructed from relatively comparable existing
groups not receiving treatment. Quasi-experimental methods are often used to assess
effects in the natural setting, where a true experiment may not be feasible.

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Appendix II: Evaluations Used Multiple
Approaches to Assess Selection Bias

One way to address issues of selection bias is in the design of the
comparison groups. Generally, random assignment of eligible participants
to treatment and control groups addresses selection bias by randomly
distributing individual differences between the treatment and control
group. Another way to address selection bias is statistically—by forming
comparison groups that consist of individuals that are as similar as
possible to drug court participants and by using statistical techniques to
control for observed differences, including sophisticated two-step
procedures that attempt to address differences in selection into the drug
court program. For the recidivism outcomes we reported, the evaluations
in our review used design and statistical methods to address selection
bias.

Evaluations in our review were either experiments or quasi-experiments.
The experiments randomly assigned eligible defendants to a drug court
program or a control group of defendants who received conventional case
processing.2 The quasi-experiments used one of two types of comparison
groups:

Evaluations
Addressed Selection
Bias through Design
•

historical comparison group—formed from individuals who received
conventional case processing during a period of time shortly before the
drug court program was implemented and

•

contemporaneous comparison group—formed from defendants (1) who
were eligible for drug court but received conventional case processing
during the same time period as the drug court program participants,
(2) who were from a district within a court’s jurisdiction from which
arrestees were not eligible to participate in the drug court program, or
(3) who had similar charges and were matched on characteristics.
If implemented as designed, experiments can provide strong evidence for
the effectiveness (or lack thereof) of a drug court intervention. A key
presumption of random assignment is that any individual factor that could
be associated with the outcome of interest (recidivism) is randomly
distributed between the experimental and control groups. Hence, if none
of these factors are correlated systematically with assignment into groups,
then the threat of selection bias is reduced. Presuming that the
randomization is complete and that the experiment was carried out

We use conventional case processing in this report to refer to the general set of criminal
justice procedures that comparison group members receive.

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GAO-05-219 Drug Court Effectiveness

Appendix II: Evaluations Used Multiple
Approaches to Assess Selection Bias

without high levels of attrition of subjects from either group, the observed
differences in recidivism between the two groups would likely arise from
the intervention, rather than observed or unobserved individual factors.
Several of the evaluations used quasi-experimental designs in which the
comparison group members were chosen from defendants who appeared
before the court during a period of time shortly before the drug court
program was introduced and, based on certain observable characteristics,
were deemed to be eligible to participate in the drug court program.
Theoretically, if there were no significant changes in processes that led to
defendants appearing in a court during the pre- and drug court periods,
and if their eligibility for drug court participation could be determined, a
historical comparison group would consist of individuals that share
characteristics with drug court defendants. Alternatively, if there were a
significant difference in processing between the pre-drug court and drug
court periods (for example, such as a shift in prosecution priorities toward
particular types of offenses or a change in the nature of a community’s
drug problem), then the historical comparison group could consist of
defendants that differed systematically from the drug court participant
group.
The historical comparison group in the evaluations we reviewed generally
consisted of defendants who were arrested and arraigned in the court that
offered the drug court program in a period immediately prior to the
implementation of the drug court. In one case, the comparison group
members were chosen from defendants on probation in the period prior to
the drug court. To minimize possible bias that could arise from changes in
court practices or the composition of defendants entering a court in the
period prior to the implementation of a drug court, in the evaluations we
reviewed, the prior periods generally ended within 4 months to 1 year
before the implementation of the drug court program.
Another subset of the evaluations we included in our review used quasiexperiments with contemporaneous comparison groups. One comparison
group consisted of defendants who met the drug court program’s eligibility
requirements but who were arrested in areas within a court’s jurisdiction
that did not enroll individuals in the drug court. Another comparison
group was formed by selecting members from other, comparable
jurisdictions. A third consisted of individuals who, while otherwise eligible
to enroll in the drug court, were unable to participate because of logistical
reasons. Others consisted of defendants charged with similar offenses as
drug court participants and who were then matched on key variables.

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GAO-05-219 Drug Court Effectiveness

Appendix II: Evaluations Used Multiple
Approaches to Assess Selection Bias

Evaluations Used a
Variety of Statistical
Methods to Minimize
the Possible Effects of
Selection Bias

All of the quasi-experiments that we reviewed, whether they used
historical or contemporaneous comparison groups, used various statistical
methods to control for individual differences between drug court
participants and comparison group members on observable variables.
Several evaluations used sophisticated statistical methods that not only
adjusted results for individual level differences but also attempted to
correct for selection bias by modeling unobserved differences between
drug court and comparison group members.3 These methods reduce but do
not completely eliminate potential bias from unobserved confounding
factors. The extent to which they reduce bias depends upon the richness
and quality of the control variables that are used to estimate the models.
These methods essentially use statistical models to predict individual
probabilities of participation in the drug court program (regardless of
actual participation). The models predict the probability, sometimes called
a propensity score, based on variation in individual level characteristics
(for example, criminal histories and demographic attributes) that
offenders in a given group would participate. Some of the evaluations that
we reviewed incorporated this technique as the first stage of a two-stage
model that estimated recidivism differences. Others used it to identify the
individuals to include in a comparison group.
Other studies matched comparison group members to drug court
participants on a more limited set of demographic and criminal justice
variables (such as type of charge and prior criminal history) and then,
post-matching, used various methods to control for differences on
unmatched variables. A presumption behind these matching methods is
that by selecting for inclusion in the comparison group only those
defendants who matched drug court participants on these observed
characteristics, the evaluation would create a comparison group that was
similar in composition to the drug court participants. A limited set of
matching variables that is based largely upon demographic variables may
be unlikely to capture all of the individual-level sources of variation in
recidivism that could account for differences between the drug court
participants and comparison group members. Therefore, these evaluations
attempted to control for differences in key, nonmatch variables (such as
criminal justice risk-level differences) in their analysis.

See, for example, Heckman, James, Hidehiko Ichimura, and Petra Todd (1997). “Matching
as an Econometric Evaluation Estimator: Evidence from a Job Training Programme,”
Review of Economic Studies, Vol. 64, No. 4, pp. 605-654.

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Appendix II: Evaluations Used Multiple
Approaches to Assess Selection Bias

Some of the evaluations attempted to control for individual-level
differences between the drug court participants and the comparison group
members using various linear and nonlinear (e.g., logistic) regression
methods. This approach relies on the assumption that the observed
characteristics included in the regression are the key variables that predict
recidivism. The regression models adjust the results for differences
between the two samples on these characteristics and allow the
researcher to avoid making incorrect inferences about recidivism
differences because one group (either treatment or comparison) differs
systematically from the other in the presence of the key variables that are
associated with recidivism. Evaluations that used regression methods
generally made efforts to control for variables that are known to be related
to recidivism, such as criminal history, type and number of charges, and
age. Table 3 describes the comparison groups used in the evaluations we
reviewed and the methods used by these evaluations to address selection
bias.

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Appendix II: Evaluations Used Multiple
Approaches to Assess Selection Bias

Table 3: Research Designs, Comparison Groups, and Methods to Address Selection Bias for Evaluations GAO Used in
Recidivism Analysis
Drug court program and design

Comparison group used in evaluation

Methods to address selection bias

Experimental design
Baltimore City Drug Treatment Court Randomly assigned from the initial pool of
willing, eligible defendants to a control group
that received “treatment as usual,” which
included less intensive drug testing,
probation, judicial monitoring, and treatment.

Random assignment to control prior to
appearance before a drug court judge, who
made final determinations for drug court entry.

D.C. Superior Court Drug
Intervention Program

Randomly assigned from the initial pool of
eligible drug court participants to a standard
(control) docket. Participants received
services such as supervision, drug tests
(twice weekly), judicial monitoring, and were
encouraged to seek community treatment.

Random assignment and various regression
methods to control for individual differences
between drug court participants and control
group members, such as age, gender, prior
criminal history, severity of drug use, and
employment status.

Maricopa County First Time Drug
Offender Program

All individuals identified as eligible for the
drug court program were randomly assigned
to one of three study groups at the time of
their initial probation assignment. The three
study groups were:

Random assignment.

1. probation with no testing;
2. probation with low-rate (monthly) drug
testing; and
3. probation with high-rate (biweekly) drug
testing.
Quasi-experimental, historical comparison group
Breaking the Cycle Program,
Birmingham

Historical arrestees: sample drawn from
arrestees in a drug use forecasting project in
the Birmingham jail over a 2-month period in
the year prior to the start of the treatment
court. Arrestees were chosen using the same
criteria to select treatment court participants:
age, county, felony charges, and involvement
with illegal drugs.

Regression methods that control for individual
differences and a two-stage estimation
procedure to account for unmeasured sample
differences.

Breaking the Cycle Program,
Jacksonville

Historical arrestees: sample drawn from
arrestees in the Duval County jail over a 4month period that ended 5 months prior to
the start of the treatment court. Arrestees
were chosen using the same criteria to select
treatment court participants: age, county of
residence (Duval), felony charges, and
involvement with illegal drugs.

Regression methods that control for individual
differences and a two-stage estimation
procedure to account for unmeasured sample
differences.

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Appendix II: Evaluations Used Multiple
Approaches to Assess Selection Bias

Drug court program and design

Comparison group used in evaluation

Methods to address selection bias

Breaking the Cycle Program,
Tacoma

Historical arrestees: sample drawn from
arrestees in the Pierce County jail over a 4month period that ended 5 months prior to
the start of the treatment court. Arrestees
were chosen using the same criteria to select
treatment court participants: age, county of
residence (Pierce), felony charges, and
involvement with illegal drugs.

Regression methods that control for individual
differences and a two-stage estimation
procedure to account for unmeasured sample
differences.

Bronx Treatment Court

Historical arrestees: defendants arrested in
the Bronx in the 4 months prior to the
opening of the drug court on selected felony
charges of criminal sale of a controlled
substance.

Propensity score matching methodology (to
identify comparison group members having
similar predicted probabilities of participating in
the drug court as drug court participants); match
model based on age, race, specific charges, and
various criminal history measures. Comparison
group members matched to the drug court
participant having the nearest propensity score.

Chester County Drug Court Program Historical probationers: defendants placed on
probation during the 10-month period prior to
the inception of the drug court program who
would have been eligible had the drug court
program existed (i.e., charged with
nonmandatory drug offenses, had no prior
violent offenses, and were not on probation
or parole).

Comparison group was similar to the drug court
sample in demographic characteristics (age,
race, and gender), prior record, and prior drug
treatment characteristics. Author and county
officials were unaware of historical events that
would have caused threats to validity of
comparison.

Escambia County Drug Court

Historical arrestees: defendants arrested and
arraigned in Escambia County over a 27month period that ended in the month prior to
the beginning of the drug court. Selected on
the same type of charges as drug court
participants.

Instrumental variable approach that controls for
the probability of participation in the drug court
program and models unobserved motivational
differences between participants and
nonparticipants.

Jackson County Drug Court

Historical arrestees: defendants arrested in
Jackson County over a 3-year period that
ended in the 15 months prior to the beginning
of the drug court. Selected on the same type
of charges as drug court participants.

Instrumental variable approach that controls for
the probability of participation in the drug court
program and models unobserved motivational
differences between participants and
nonparticipants.

Queens Treatment Court

Historical arrestees: defendants arrested in
Queens in the year prior to the opening of the
drug court on a most serious charge of
criminal sale or possession of drugs (that met
charge eligibility for drug court). Excluded
defendants who did not meet the drug court’s
paper eligibility criteria, i.e., current and prior
violence and those cases in which the arrest
did not lead to a conviction.

So. San Mateo County Drug Court

Historical arrestees: defendants arrested and
processed before the start of the drug court
but who would have been eligible for the drug
court.

Regression methods to control for individual
differences on key variables, such as ethnicity,
prior convictions, primary language, and severity
of charges.

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Appendix II: Evaluations Used Multiple
Approaches to Assess Selection Bias

Drug court program and design

Comparison group used in evaluation

Methods to address selection bias

Suffolk County Drug Treatment
Court

Historical arrestees: defendants arrested in
Suffolk County in the year prior to the
opening of the drug court on a most serious
charge of felony or misdemeanor criminal
possession of a controlled substance (that
met eligibility for drug court). Excluded
defendants with current violent charges or
prior violent convictions and those cases in
which the arrest did not lead to a conviction.

Syracuse Community Treatment
Court

Historical arrestees: defendants arrested in
Syracuse City in the year prior to the opening
of the drug court on a most serious charge of
felony or misdemeanor criminal possession
of a controlled substance (that met drug court
charge eligibility). Excluded defendants with
prior violent convictions or pending violent
charges and those cases in which the arrest
did not lead to a conviction.

Quasi-experimental, contemporaneous comparison group
Brooklyn Treatment Court

Contemporaneous: drug felony defendants
arrested in Brooklyn but not screened in the
drug court, primarily because they were
arrested within one of the two geographic
zones that were ineligible to send defendants
to the drug court. Defendants met the same
paper eligibility criteria as drug court
participants. Excluded defendants with prior
violent felony or misdemeanor convictions,
with current violent offense charges, and
those cases in which the arrest did not lead
to a conviction.

Clark County Drug Court

Contemporaneous arrestees: sample drawn
from criminal defendants who had charges
filed in the Clark County District Courts but
did not enter the drug court. Sample stratified
on drug type and type of charge.

Regression methods to control for individual
differences in gender, race/ethnicity, age, prior
convictions, number of charges and types of
charges (e.g., drug possession or sales and
economic crimes), prior controlled substances
types, and recidivism in the year after
sentencing.

Douglas County Drug Court

Contemporaneous: felony drug arrestees
who had charges filed in court and
a
traditionally adjudicated. Most had no more
than one prior felony conviction, and few had
been convicted of a prior violent felony.
Slightly less than half were characterized as
medium- or high-risk offenders.

Matched to drug court participants on most
serious offense, gender, race and ethnicity, and
age. Risk-level data were not available for this
group. Regression methods to control for prior
criminal history.

Kentucky Drug Court Programs

Contemporaneous: assessed offenders,
Regression methods to control for individual
combined felony and misdemeanor charge or differences in age, gender, race, location of
conviction.
court, year of participation, and criminal justice
involvement.

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Appendix II: Evaluations Used Multiple
Approaches to Assess Selection Bias

Drug court program and design

Comparison group used in evaluation

Methods to address selection bias

Los Angeles County Drug Court
Program

Contemporaneous: felony offenders charged
with drug possession but sentenced at trial to
probation. Drawn from the same pool of
offenders screened for participation in the
drug court.

Matched with the sample of drug court
defendants of a risk scale score (a composite
scale based on criminal justice and social factors
and used to determine release risk), time of
hearing, gender, and age. Separate analyses
done between drug court and both comparison
group members having various levels of risk.

Multnomah County STOP Drug
Diversion Program

Contemporaneous arrestees who were
eligible for the STOP program but did not
receive it. Arrested for possession of
controlled substance and considered to be
eligible for STOP but did not receive it.

Matched sample approach to select a group of
eligible clients who were representative of
program participants on age, gender, race/
ethnicity, and prior criminal history.

North Carolina Drug Treatment
Court

Contemporaneous probationers who would
have been eligible for the drug court but were
not admitted. Comparison group was
screened for chemical dependence and
sample selected based on drug addiction
(from screening) and eligibility for drug court.

Regression methods to control for individual
differences in age, gender, ethnicity, type of
offense (for example, property or drug), offense
seriousness, and graduation status.

Orange County Drug Court Program Contemporaneous defendants who had
Matched to drug court participants on gender,
similar charges as the drug court participants race and ethnicity, and age.
and were sentenced to probation. Drawn
from the same pool of offenders screened for
participation in the drug court.
Rochester Drug Treatment Court

Contemporaneous arrestees: defendants
arrested in Rochester during the same period
of time as the drug court was in operation but
who were not arraigned before judges
supportive of the drug court program.
Excluded defendants that did not meet the
drug court’s paper eligibility criteria (i.e.,
current and prior violence) and those cases
in which the arrest did not lead to a
conviction.

Quasi-experimental, both historical and contemporaneous comparison groups
Washington State Court Program

Historical and contemporaneous defendants: Various statistical methods including regressions
Historical group: defendants with cases filed to control for individual differences in age,
gender, ethnicity, prior youth and adult
in the 2 years prior to the start of the drug
convictions, current charges; propensity score
court in each of the county drug court
matching to identify comparison group members
programs included in the evaluation.
with similar predicted probabilities of entering the
Contemporaneous group: defendants with
drug court.
similar cases who were processed in
counties without drug courts that were
comparable to the counties that did have
drug courts.
Source: GAO analysis of drug court program evaluations.
a

While these defendants consisted primarily of those arrested during the time the drug court program
was in operation (a contemporaneous comparison), some individuals who were arrested in the
3 months prior to the start of the drug court program were included.

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GAO-05-219 Drug Court Effectiveness

Appendix III: GAO Criteria for Assessing
Evaluations of Drug Court Programs’ CostBenefit Analyses

Appendix III: GAO Criteria for Assessing
Evaluations of Drug Court Programs’ CostBenefit Analyses
In this appendix, we outline the criteria we used in assessing the costbenefit analyses of drug court program evaluations, and we discuss how
the evaluations we reviewed followed these criteria in their analyses.

The Evaluations We
Reviewed and the Net
Benefit Measure

Cost-benefit analysis determines the costs associated with implementing
or operating a program and weighs that cost against any benefits expected
from the program. The results of a cost-benefit analysis can be represented
as either a net benefit—calculated as total benefits minus total costs—or a
benefit-to-cost ratio—calculated as total benefits divided by total costs.
We used the net benefit—benefit minus cost—measure to represent the
cost-benefit analyses of the drug court programs we reviewed. Net benefit
can be used to evaluate the cost savings—that is, the benefits—for each
participant in a drug court program relative to the cost savings for each
offender processed by conventional case processing in the same
jurisdiction.
To assess the cost-benefit analyses of drug court program evaluations, we
reviewed all of the evaluations selected for our structured review that
reported cost or benefit information. Of the 27 evaluations included in the
structured review, 8 reported information about program costs and
4 about benefits. The 8 evaluations we included in our cost-benefit review
are shown in table 4.

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Table 4: The Eight Drug Court Program Evaluations in Our Cost-Benefit Review
Reported data on
Drug court program evaluation

Benefits

Costs

Breaking the Cycle Program
(Harrell and others, 2003)

Yes

D.C. Superior Court Drug Intervention Program
(Harrell, Cavanagh, and Roman, 1998)

Yes

Multnomah County (Ore.) STOP Drug Diversion
Program (Carey and Finigan, 2003)

Yes

Washington State Drug Court Program
(Barnoski and Aos, 2003)

Yes

Douglas County (Neb.) Drug Court
(Martin, Spohn, Piper, and Frenzel-Davis, 2001)

Yes

Kentucky Drug Court Programs
(Logan, Hoyt, and Leukefeld, 2001)

Yes

Los Angeles County (Calif.) Drug Court Program
(Deschenes and others, 1999)

Yes

Maricopa County First Time Drug Offender
Program (Deschenes and others, 1996)

Yes

Included in cost-benefit analysis

Not included in cost-benefit analysis

Source: GAO analysis of drug court program evaluations.

Four of the 8 evaluations reported sufficient data on both costs and
benefits, which allowed us to assess the reported net benefits of the drug
court programs. Specifically, we were able to determine whether the
reduction of recidivism—the benefit—would outweigh the additional costs
of a program.

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Criteria for Assessing
a Drug Court
Program’s CostBenefit Analysis

Conducting a cost-benefit analysis is theoretically straightforward—
determine the monetary value of a program’s benefits and compare that
value with the monetary value of the program’s costs. However, the
analysis is more complicated in practice because of decisions that have to
be made about who to include as recipients of the benefits and how to
measure costs and benefits.1 On the basis of the general principles of costbenefit analysis, we identified five criteria that we used in assessing the
cost-benefit analyses of the drug court programs we reviewed. Table 5
describes these criteria; where further explanation is needed, we discuss
them in the text that follows.

Table 5: Five Criteria for Assessing a Cost-Benefit Analysis of a Drug Court Program
Criterion

Description

1. States the program’s purpose

In general, the purpose of a drug court program is to reduce repeated criminal behavior—to
reduce recidivism—by reducing offenders’ substance-using behavior.

2. Identifies the baseline

The baseline, or alternative, is what would happen to an offender if the drug court program
did not exist.

3. Assesses all relevant costs

The costs involved in a drug court program are those associated with the program’s
operation and those associated with the baseline.

4. Assesses all relevant benefits

Benefits usually attributed to drug court programs are costs avoided because of reduced
recidivism; they accrue to the criminal justice system and potential victims of crime. Other
benefits an analysis could consider include reduced medical costs and successful program
participants’ increased productivity.

5. Assesses uncertainty in cost and
benefit estimates

Most cost and benefit estimates entail uncertainty from imprecision in the data underlying
the analysis and the assumptions built into the analysis. Assessing uncertainty enhances
confidence in the estimates used in evaluation.
Source: GAO analysis.

Identifies the Baseline

A cost-benefit analysis should identify what the baseline program is. In the
case of drug court programs, the analysis should state what would happen
to an offender if the drug court program did not exist. The costs and
benefits of this alternative program or case processing, called the baseline,
are the standard by which the drug court program costs and benefits are
judged. There is no single baseline against which all drug court programs
are compared. For example, one jurisdiction may offer drug court program

Generally, a cost is the value of resources used to achieve a benefit. Economic costs
consider the opportunity cost, which is the value of the resources in their best alternative
use. The costs to and the benefits that accrue to all members of society, rather than just to
its taxpaying members, should be included in the analysis. For example, benefits from a
decrease in crime, such as reduced victimization, accrue to all members of society,
regardless of whether they are taxpayers, and should be included.

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participation to defendants as an alternative for jail, another as an
alternative for probation.

Assesses All Relevant
Costs

A cost-benefit analysis should enumerate and assess all relevant costs. A
cost-benefit analysis of a drug court program should consider two sets of
costs—those associated with the program’s operation and those
associated with the baseline. For both sets of costs, the analysis should
determine which costs are relevant and then measure them.

Determining Relevant Costs

Drug court programs often require additional expenses from criminal
justice system agencies, although these may differ from program to
program. The true cost of a drug court program consists of these
expenses—the resources that would have been used in their next best
alternative use—if not used for the program. Drug court programs have
several basic elements, one of which is ongoing monitoring of the
participants by a judge or other personnel in the criminal justice system.2
Others are regular status hearings and drug testing, substance abuse
treatment, and the prescription of sanctions for noncompliance with
program requirements. While an analysis should consider all of these
costs, it should not consider costs that were incurred before the program
began (that is, sunk costs) since they are not relevant to the current
decision to fund or continue funding the program.
In addition to the program’s costs, the analysis should include the costs of
the baseline. These depend on the types of offenders who are eligible for
the drug court program in each jurisdiction and the alternative program or
processing available for them. The baseline costs may include the cost of
traditional adjudication (including a judge’s time during the early phases
of judicial processing), the costs of jail time served, or costs of probation
(such as the salaries of probation officers or any required monitoring).

Measuring Drug Court Program
and Baseline Program Costs

The various methods of measuring or estimating costs require varying
amounts of time, data, and analysis. The most straightforward way of

In an assessment of the costs associated with the salaries of criminal justice personnel,
costs that are directly attributable to the drug court program (such as the salary of a fulltime drug court judge) should be included. Costs that are incurred jointly by the program
and other activities (such as costs for probation officers with shared caseloads) should be
allocated among the program and the activities, according to some generally accepted
accounting principles or standards. Finally, costs that would be incurred in the absence of
the program (such as costs for nondedicated police personnel) should be excluded from
the analysis.

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measuring the costs of both a drug court program and the baseline is to
use budget or expenditure figures from the agencies involved to calculate
average costs.3 While this method has the advantage of simplicity, average
cost may be a misleading measure of resource costs if it does not
accurately portray the resources defendants actually used.
For example, a few very high cost program participants could skew the
average cost to such an extent that actual cost appears to be larger than it
is. This is especially important in assessing average costs associated with
the baseline program. The average baseline defendant in a jurisdiction may
be very different from participants in a drug court program. Therefore,
comparing costs associated with the average defendant with those of the
average drug court participant may not be valid.
A less simple approach, requiring a more intensive use of time and data, is
to conceptualize the cost of drug court program participation as a series of
transactions within the criminal justice system agencies.4 Since a
defendant interacts with a number of these agencies, this method requires
obtaining data about each defendant from each agency. These data can be
aggregated for individual defendants to determine the total amount of
resources used per participant, and these resources can then be multiplied
by their price. This approach has the advantage of allowing a better
determination of the true cost of drug court participation, relative to
participation in an alternative program. However, since it is more labor
intensive, jurisdictions may not have records organized in a way that
allows for tracking individuals across agencies.

Assesses and Measures All
Relevant Benefits

As with costs, all relevant benefits of the drug court program should be
assessed relative to the baseline.5 The typical benefit attributed to drug

Average costs are calculated by dividing the budget totals by the number of drug court
program cases in a given year and by the number of baseline, or nondrug, cases in the same
year.
4

This is called the transaction cost approach. For more information about this
methodology, see Carey, S. M., and M. W. Finigan, A Detailed Cost Analysis in a Mature
Drug Court Setting: A Cost-Benefit Evaluation of the Multnomah County Drug Court,
(Portland, Ore.: NPC Research, July 2003).
5

The present value of estimated costs and benefits should be calculated. Researchers
should identify the follow-up period in which the benefits would accrue. The value of
future benefits should be discounted by an appropriate interest rate, to account for the fact
that these benefits are deferred.

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court programs is avoided costs from reductions in recidivism. Other
benefits that could be considered in the analysis include reduced medical
costs and increased worker productivity stemming from reduced drug
dependency.
Reductions in recidivism can lead to benefits, or cost savings, for criminal
justice agencies and for potential victims of crime. A reduction in the
number of arrests would result in a reduction in expenditures for the
agencies, including police, prosecutors, courts, corrections departments,
and probation agencies.
Potential victims benefit from reduced recidivism. Benefits accrued
because of reduced victimization include direct monetary costs, such as
the value of stolen property and medical expenses, and quality-of-life costs
related to pain and suffering. Not including pain and suffering costs would
underestimate the true cost of crime, but some researchers exclude these
intangibles because it is difficult to assign appropriate dollar values to
them. This results in a more conservative estimate of the benefit of the
drug court program.
In addition, the analysis should, to the extent possible, assess benefits to
society from a reduction in substance abuse. These benefits may include
avoided medical care costs, such as medical services a treated drug addict
did not require. Additionally, if drug court programs are effective, the
labor market outcomes of the participants may improve. For example,
successful participants may be unemployed less often or may earn higher
wages because of increased productivity. To the extent that they may
therefore pay higher taxes, such taxes are benefits to taxpayers in general.6

Challenges in Measuring Drug
Court Program Benefits

The simplest approach to measuring the benefits of reduced recidivism is
using arrest data. This approach has the appeal that an arrest is usually the
beginning of expenditures by a criminal justice agency. Then, the value of
this benefit per arrest can be estimated in the same way that costs are
estimated—by using agency budgets to calculate the average savings from
each avoided arrest.

These benefits may be difficult to quantify, but earnings and employment data could be
estimated through surveys of participants or could be obtained from state unemployment
insurance agencies.

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It is possible to measure criminal victimization by using arrest data as
well. However, this approach requires the assumption that each criminal
act results in an arrest. To the extent that this is not true, the estimation of
victimization may be underestimated by a significant margin. Another
approach to measuring victimization would be to use self-reported
criminal behavior by the drug court program and comparison group
participants. However, this approach relies on the forthrightness of the
defendants, which is not ideal. Since both of these methods have
drawbacks, any measurement of criminal victimization is much more
uncertain than measures of expenditures by the agencies.
Measuring the cost of crime may also be problematic. Estimates of the
costs of crimes at the national level are available in the literature.7 For
example, these can provide an estimate of the cost of a burglary, and a
researcher can apply the cost to the number of burglaries by the
participant. Ideally, an analysis would also include the costs of crimes
specific to the drug court program’s jurisdiction to account for regional
differences. For example, the average value of a car stolen in Miami might
be different from the average value of a car stolen in Tallahassee.

Assesses Uncertainty in
Cost and Benefit Estimates

The uncertainty in most cost and benefit estimates is the result of
imprecision in the underlying data used in the analysis and the
assumptions on which the analysis is built. Assessing uncertainty can
enhance the confidence in the estimates in the evaluation. Useful
information for an analysis to report includes the estimates of costs and
benefits and the sensitivity of the cost and benefit estimates to
assumptions made in the analysis.
Estimates of costs and benefits should take into account how likely it is
that a particular outcome (for example, arrest for a crime that will warrant
participation in the drug court program) will occur, in addition to the value
(for example, the cost to victims, the criminal justice expenditures) of that
outcome. Taking account of the likelihood of occurrence allows the
researcher to provide a better assessment of how reliable the data—the
costs and benefits—are.

A commonly cited reference is Miller, T. R., M. A. Cohen, and B. Wiersema, Victim Costs
and Consequences: A New Look (Washington, D.C.: National Institute of Justice, Office of
Justice Programs, Department of Justice, January 1996).

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Uncertainty also derives from assumptions made in an analysis. In an
assessment of an analysis, it is helpful to know which assumptions can be
changed without altering the conclusion of the analysis. Sensitivity
analysis, or systematically varying the assumptions to see what effect
variations have on estimated outcomes, can be applied to several
components of a drug court program’s cost analysis.8 For example, one
assumption in the criminal justice area is the numerical relationship
between the commission of a crime and the arrest rate. Not every crime
results in an arrest, but a cost-benefit analysis may have been able to
examine only arrest data, given the lack of other data available. Using
arrest data assumes, in effect, that every crime does result in an arrest—an
assumption that is likely to underestimate the change in crime that the
public experiences. A sensitivity analysis could examine this possible
understatement by increasing the study’s assumed rate of crime per arrest
(for example, the Washington State study assumes that 20 percent of
robberies result in an arrest) to better approximate the actual crime rate.

How the Drug Court
Evaluations We
Reviewed Used the
Identified CostBenefit Principles

We reviewed eight evaluations of 10 drug court programs for their use of
the criteria. At least five of these evaluations made a concerted effort to
assess all relevant costs as well as benefits. Only two evaluations assessed
uncertainty. However, the two evaluations that conducted sensitivity
analyses were two of the three that did not present costs and benefits
separately so as to allow for an assessment of net benefits. Table 6
summarizes the evaluations we reviewed and their application of the five
criteria in their assessments.

A sensitivity analysis does not, however, provide information about the range and
distribution of the possible values of a given outcome. Additional analysis can allow a
researcher to determine the likely range of an estimated outcome. In essence, additional
analysis can provide an upper and a lower bound of an estimate, giving an indication of
how much uncertainty there is in the outcome. For example, researchers may estimate how
much time a judge spends on a drug court program participant’s case, and the estimate may
be high or low. The range of possible values of time spent by a judge can be defined, which
can help in assessing how reliable the costs associated with a judge’s time are in an
analysis.

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Table 6: Summary of Criteria Applied in Eight Drug Court Program Evaluation Assessments
Assessed costs
Drug court program
evaluation

Stated
purpose

Identified
baseline

Birmingham, Ala.

Yes

Jacksonville, Fla.

Yes

Tacoma, Wash.

Assessed benefits

Baseline

Recidivism Other

Assessed
uncertainty

Yes

Drug court

BTC Program (Harrell
and others, 2003)

Yes

D.C. Superior Court
Yes
Drug Intervention
Program (Harrell,
Cavanagh, and Roman,
1998)

Yes

Douglas County (Neb.)
Drug Court (Martin,
Spohn, Piper, and
Frenzel-Davis, 2001)

Yes

Kentucky Drug Court
Yes
Programs (Logan, Hoyt,
and Leukefeld, 2001)

Yes

Los Angeles County
(Calif.) Drug Court
Program (Deschenes
and others, 1999)

Yes

Maricopa County First
Time Drug Offender
Program (Deschenes
and others, 1996)

Yes

Multnomah County
(Ore.) STOP Drug
Diversion Program
(Carey and Finigan,
2003)

Yes

Washington State Drug
Court Program
(Barnoski and Aos,
2003)

Yes

Source: GAO analysis of drug court program evaluations.
a
The Kentucky study does include estimates of benefits from reduced recidivism, but does not appear
to include victimization costs.

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Evaluations of Drug Court Programs’ CostBenefit Analyses

All Evaluations Stated the
Program’s Purpose

All eight evaluations provided a statement of the purpose of the drug court
program, although the purpose of the programs varied somewhat one from
another. Evaluations of some of the programs—for example, those in
Kentucky, Washington, D.C., and Multnomah County—explicitly stated
that the purpose was to address the source of criminal behavior—drug
addiction, dependency, and the like—in order to reduce recidivism. None
of the evaluations, however, included reduced drug dependency in their
calculation of net benefits.

All Evaluations Identified a
Baseline

Of the eight evaluations we reviewed, five compared drug court program
participants with the baseline of conventional case processing in the
criminal courts in their jurisdictions. The evaluation of the D.C. Superior
Court Drug Intervention Program used a different baseline for
comparison. This program was an experiment that randomly assigned
drug felony defendants to one of three court dockets. The standard docket
offered defendants weekly drug testing, judicial monitoring, and
encouragement to seek treatment in the community. The sanctions docket
offered a program of graduated sanctions with weekly drug testing,
judicial monitoring of drug use, and referral to community-based
treatment. The treatment docket offered weekly drug testing and an
intensive daily treatment program based in D.C. Superior Court. The
evaluation studied the sanctions and treatment docket participants against
the outcomes of the standard docket participants.

The Evaluations Varied in
Assessing Costs

The eight evaluations varied in the types of costs reported. All eight
included only costs directly attributable to drug court programs. None
attempted to allocate any shared costs incurred jointly by a drug court
program and another activity not directly related to the program (such as
policing). Further, no evaluation included sunk costs. All eight evaluations
included direct program costs such as urine analysis. However, they varied
in reporting costs for adjudication and sanctions. Six of the eight
evaluations included costs of adjudication or sanctions.9

Breaking the Cycle, D.C. Superior Court, Multnomah County, and Washington State
evaluations considered adjudication and sanctions cost. Douglas County did not include
sanctions costs, while Maricopa County did include confinement and supervision costs.
The Los Angeles and Kentucky drug court program evaluations did not include
adjudication or sanction costs.

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Including Baseline Costs

All of the evaluations, except for the Kentucky state evaluation, attempted
to include the cost of the baseline in the analysis. Consequently, this
evaluation did not report a net benefit value.

Estimating Costs

The evaluations varied in how they estimated costs. The most common
method was to compute average costs. The Multnomah County evaluation
differed in that it determined the cost to the agencies directly from the
administrative records on the drug court program participants and the
comparison group. In addition, the researchers on this evaluation followed
a smaller sample of drug court program and control group participants
through the system, tracking the use of resources in the various
transactions associated with them. For example, the researchers used a
stopwatch at arraignments to determine how much time the judge and
other drug court staff spent in this process.

The Evaluations Varied in
Assessing Benefits

In their estimation of benefits attributable to the drug court programs, five
of the evaluations included estimates of drug court program and criminal
justice system costs and avoided victimization costs (Breaking the Cycle,
the D.C. Superior Court Drug Intervention Program dockets, Kentucky,
Multnomah County, and Washington State). The D.C. Superior Court and
Breaking the Cycle evaluations differed substantially from the others in
both the method of measuring victimization and the victim costs. Rather
than using arrest as the indicator of crimes committed, the evaluations
used self-reported criminal activity. In addition, the studies did not use
“quality of life” costs in their measure of cost of crime.
One evaluation estimated just drug court program costs avoided (Douglas
County, Nebraska). One evaluation (Los Angeles County) included only
criminal justice system costs avoided during the treatment period, but it
did not cover recidivism. The Maricopa County evaluation only reported
average costs.

The Evaluations’
Assessment of Uncertainty
Was Limited or
Nonexistent

No evaluation we reviewed presented the likelihood of estimated costs
and benefits, and only two evaluations conducted sensitivity analysis. In
the Los Angeles County Drug Court evaluation, participants were
partitioned into low-risk, medium-risk, and high-risk groups, on the basis
of criminal history and other risk factors. The Kentucky Drug Court
Program evaluation placed its estimates of the benefit-to-cost ratio within
ranges that depended on whether accounting or economic costs were
included, and it included earnings improvements.

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Appendix IV: Overview of Drug Court
Program Characteristics and Participants

Appendix IV: Overview of Drug Court
Program Characteristics and Participants
This appendix provides a general description of drug court program
components and describes program participants in the evaluations we
reviewed. Drug court programs rely on a combination of judicial
supervision and substance abuse treatment to motivate defendants’
recovery. Judges preside over drug court proceedings, which are called
status hearings; monitor defendants’ progress with mandatory drug
testing; and prescribe sanctions and rewards, as appropriate in
collaboration with prosecutors, defense attorneys, treatment providers,
and others. Drug court programs can vary in terms of the substance abuse
treatment required. However, most programs offer a range of treatment
options and generally require a minimum of about 1 year of participation
before a defendant completes the program. Drug court program
participants can vary across programs according to differences in
eligibility requirements and jurisdictions. The participants in the drug
court programs we reviewed were predominantly male, generally
unemployed at the time of program entry, and had prior involvement in the
criminal justice system.

Drug Court Program
Components

This section describes typical drug court program approaches, screening
processes and participant eligibility requirements, completion
requirements, treatment components, and sanctions.

Drug Court Program
Approaches

Drug court programs generally have taken two approaches to processing
cases: (1) deferred prosecution (diversion) and (2) post-adjudication. In
the diversion model, the courts defer prosecution dependent on the
offender’s agreement to participate in the drug court program. Deferred
adjudication models do not require the defendant to plead guilty. Instead
the defendant enters the drug court before pleading to a charge.
Defendants who complete the treatment program are not prosecuted
further or their charges are dismissed. Failure to complete the program
results in prosecution for the original offense. This approach is intended to
capitalize on the trauma of arrest and offers defendants the opportunity to
obtain treatment and avoid the possibility of a felony conviction.
In contrast, offenders participating in a post-adjudication (post-plea) drug
court program plead guilty to the charge(s) and their sentences are
suspended or deferred. Upon successful completion of the program,
sentences are waived and in many cases records are expunged. This
approach provides an incentive for the defendant to rehabilitate because
progress toward rehabilitation is factored into the sentencing

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Program Characteristics and Participants

determination. Both of these approaches provide the offender with a
powerful incentive to complete the requirements of the drug court
program.
Some drug court programs use both deferred prosecution and postadjudication approaches and assign defendants to an approach depending
on the severity of the charge. Additionally, drug court programs may also
combine aspects of these models into a hybrid, or combined, approach.

Screening Process and
Participant Eligibility
Criteria

Defendants reach the drug court program from different sources and at
varying points in case processing. Screening defendants to determine
eligibility for a drug court program generally includes screening them for
legal and clinical eligibility. Initially, defendants are screened for legal
eligibility, based on criminal history and current case information.
Depending on the program, an assistant district or prosecuting attorney,
court clerk, or drug court coordinator typically conducts the review.
Criteria for legal eligibility typically include charging offense, prior
convictions, pending cases, and supervision status. Drug courts generally
accept defendants charged with drug possession or other nonviolent
offenses such as property crimes. Some drug court programs allow
defendants who have prior convictions to participate, and others do not.
Federal grants administered under Title II of the 21st Century Department
of Justice Appropriations Authorization Act are not supposed to be
awarded to any drug court program that allows either current or past
violent offenders to participate in its program.1
After defendants are determined to be legally eligible for the program,
treatment providers or case managers will typically determine defendants’
clinical eligibility. This can be determined through structured assessment
tests, interviews, or even preliminary drug test results. While drug courts
generally only accept defendants with substance abuse problems, they
vary in the level of addiction or type of drug to which defendants are

Section 2953 of Title II defines “violent offender” to mean a person who “(1) is charged
with or convicted of an offense, during the course of which offense or conduct (A) the
person carried, possessed, or used a firearm or dangerous weapon; (B) there occurred the
death of or serious bodily injury to any person; or (C) there occurred the use of force
against the person of another, without regard to whether any of the circumstances
described in subparagraph (A) or (B) is an element of the offense or conduct of which or
for which the person is charged or convicted; or (2) has one or more prior convictions for a
felony crime of violence involving the use or attempted use of force against a person with
the intent to cause death or serious bodily harm.”

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Program Characteristics and Participants

addicted. For example, some programs do not accept defendants who only
have addictions to marijuana or alcohol, while others do.
Clinical eligibility can also include factors such as medical or mental
health barriers and motivation or treatment readiness. In several drug
court programs in our review, the drug court judge’s satisfaction with or
assessment of an offender’s motivation and ability to complete the
program was a factor used to screen defendants.

Program Completion
Requirements

Drug court programs typically require defendants to complete a 1-year
treatment program in order to graduate from or complete the program.
Some programs impose other conditions that participants must meet in
addition to treatment. These conditions could include remaining drug-free
for a minimum amount of time, not being arrested for a specified period of
time, maintaining employment or obtaining an educational degree or
certification, or performing community service.

Judicial Supervision and Status
Hearings

The central element of all drug court programs is attendance at the
regularly scheduled status hearings at which the drug court judge
monitors the progress of participants. Monitoring is based on treatment
provider reports on such matters as drug testing and attendance at
counseling sessions. The judge is to reinforce progress and address
noncompliance with program requirements. The primary objectives of the
status hearing are to keep the defendant in treatment and to provide
continuing court supervision. More broadly, judicial supervision includes
regular court appearances and direct in-court interaction with the judge,
as well as scheduled case manager visits.

Drug Testing Requirements

Monitoring participants’ substance use through mandatory and frequent
testing is a core component of drug court programs. Programs vary in the
specific policies and procedures regarding the nature and frequency of
testing. For example, in some programs in our review participants were
required to call to find out whether they are required to be tested in a
given period or on a randomly selected day of the week. The frequency of
testing generally varied depending on the stage or phase of the program
that participants were in.

Treatment Components

In most drug court programs, treatment is designed to last at least 1 year
and is generally administered on an outpatient basis with limited inpatient
treatment, as needed, to address special detoxification or relapse
situations. Many of the programs operate with the philosophy that because

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Program Characteristics and Participants

drug addiction is a disease, relapses can occur and that the court must
respond with progressive sanctions or enhanced treatment, rather than
immediate termination.
Treatment services are generally divided into three phases. Detoxification,
stabilization, counseling, drug education, and therapy are commonly
provided during phases I and II, and in some instances, throughout the
program. Other services relating to personal and educational development,
job skills, and employment services are provided during phases II and III,
after participants have responded to initial detoxification and stabilization.
Housing, family, and medical services are frequently available throughout
the program. In some instances, a fourth phase consisting primarily of
aftercare-related services is provided. The objectives of drug court
program treatment are generally to (1) eliminate the program participants’
physical dependence on drugs through detoxification; (2) treat the
defendant’s craving for drugs through stabilization (referred to as
rehabilitation stage) during which frequent group or individual counseling
sessions are generally employed; and (3) focus on helping the defendant
obtain education or job training, find a job, and remain drug free.
Drug court programs can also either directly provide or refer participants
to a variety of other services and support, and they may include medical or
health care, mentoring, and educational or vocational programs. The use
of community-based treatment self-help groups, such as Alcoholics
Anonymous (AA) and Narcotics Anonymous (NA), and aftercare programs
also varies across drug court programs.

Sanctions for
Noncompliance

Judges generally prescribe sanctions and rewards as appropriate in
collaboration with prosecutors, defense attorneys, treatment providers,
and others. Typical sanctions for program noncompliance include oral
warnings from the judge; transfer to an earlier stage of the program;
attendance at more frequent status hearings, treatment sessions, or drug
tests; and serving jail time for several days or weeks. The approach or
philosophy for how a drug court judge prescribes sanctions can vary. For
example, some judges use a graduated sanctions approach, where
sanctions are applied in increasing severity. Other judges may use
discretion in prescribing sanctions, assessing participants’ noncompliance
on a case-by-case basis.

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Appendix IV: Overview of Drug Court
Program Characteristics and Participants

Termination Criteria

Drug court programs typically use various criteria for ending a defendant’s
participation in the program before completion. These criteria may include
a new felony offense, multiple failures to comply with program
requirements such as not attending status hearings or treatment sessions,
and a pattern of positive drug tests.
Before terminating a defendant for continuing to use drugs, drug court
programs generally will use an array of treatment services and available
sanctions. There are no uniform standards among all programs on the
number of failed drug tests and failures to attend treatment sessions that
lead to a participant’s termination. Drug court program judges generally
make decisions to terminate a program participant on a case-by-case basis,
taking into account the recommendations of others, including the
treatment provider, prosecutor, and defense counsel. Relapses are
expected, and the extent to which noncompliance results in terminations
varies from program to program. Once a defendant is terminated, he or she
is usually referred for adjudication or sentencing.

Drug Court Program
Participants

All of the evaluations we reviewed reported some basic substance use or
demographic data about the drug court program participants. However,
not every evaluation reported the same types of information or provided
equivalent levels of detail.

Participants’ Substance
Use Characteristics

The types of drugs participants reported using varied. Cocaine (crack or
powder) was selected by the highest percentage of participants as the
primary drug of choice in most of the programs reporting these data.2
However, in Baltimore, 77 percent reported heroin was primary drug of
choice, whereas 43 percent of participants in the Tacoma, Washington,
Breaking the Cycle program reported using methamphetamine, suggesting
regional differences in drugs of choice. Participants in evaluations we
reviewed did not always report “hard” drugs as their primary substances of
choice. In several evaluations we reviewed, participants reported that
alcohol or marijuana was their primary drug of choice. For example, in
Chester County, 47 percent of participants reported marijuana, and

The evaluations used different measures to report drug use, such as “primary drug of
choice,” “used in the past 30 days,” or “used in the 90 days before program entry.”
Participants may indicate using more than one substance.

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Appendix IV: Overview of Drug Court
Program Characteristics and Participants

84 percent of participants in Maricopa County reported alcohol as primary
drugs of choice.

Selected Demographic and
Socioeconomic
Characteristics

The participants in the drug court programs we reviewed were generally in
their early 30s, predominantly male, and generally unemployed at the time
of program entry. Participants’ average age at program entry ranged from
24 years (in a misdemeanor-only drug court program in New Castle
County, Delaware) to 36 years (in the Baltimore City Drug Treatment
Court).3 In the majority of these evaluations, participants were, on average,
between 30 and 35.
Participants were also predominantly male. The percentage of male
defendants participating in drug court programs we reviewed ranged from
46 percent in Bakersfield, California, to 88 percent in the Jacksonville,
Florida, Breaking the Cycle program. Generally, however, about 60 to
80 percent of participants in these programs were male, which
corresponds to other reviews estimating that across multiple drug court
programs about 70 percent of participants are male.
In about half of the evaluations we reviewed that reported data about
participants’ race or ethnicity, the majority (50 percent or more) of the
participants were white. However, in some programs, most participants
(that is, over 75 percent of the sample) were predominantly of one racial
or ethnic background. For example, in five of the six Washington state
drug court programs, between 79 and 92 percent of participants were
white; and in the Baltimore and Washington, D.C., drug court programs,
between 89 and 99 percent of participants were black. Some other
programs reported that the participants were not predominantly of one
racial or ethnic background. For example, in Los Angeles County,
23 percent of participants were white, 30 percent black, and 43 percent
Hispanic or other.
Drug court participants in the evaluations we reviewed that reported data
on employment and educational status were generally unemployed with
less than a high school education at program entry. Between 16 to
82 percent of participants were employed at the time of entry into the

Most evaluations we reviewed reported average age. However, some reported median age,
which ranged from 23 to 34 years.

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Appendix IV: Overview of Drug Court
Program Characteristics and Participants

program.4 However, in about two-thirds of the programs reporting these
data, less than half of the participants were employed at the time of entry
into the drug court program. Similarly, in evaluations that reported
information about participants’ educational status, 24 to 75 percent of
participants reported that they had less than a high school education at the
time of entry into the program. Generally, about 30 to 60 percent had less
than a high school education at the time of entry into the program. For
example, in the New York State evaluation, across the programs, the
median percentage of participants who have received a general
equivalency diploma (GED) or high school diploma is 45 percent;
similarly, the median percentage employed or in school is 34 percent.

Criminal Justice Histories

Participants’ prior involvement in the criminal justice system, as reported
in evaluations we reviewed, was generally considerable.5 Most participants
were not first-time offenders. However the types and severity of
involvement varied. In the evaluations that reported these data, the
average number of prior arrests (of any kind) ranged from about 1 to
about 13 per participant over different time periods, ranging from 1 to
5 years before entry into the drug court program. Additionally, in the six
New York State drug court programs, the percent of participants with
prior convictions ranged from 19 percent in Queens, which says it does not
accept participants with prior felony convictions, to 69 percent in
Syracuse. However, the researchers note that less than one-third of prior
convictions in all courts were drug-related, which indicates that
participants are involved in a wider range of criminal activity. This
description of drug court participants’ criminal justice system involvement
in the evaluations we reviewed was similar to descriptions reported by
other sources. For example, the Drug Court Clearinghouse and Technical
Assistance Project’s 2001 survey of responding adult drug court programs

The 82 percent employed occurred in the Las Cruces Municipal DWI Court, the only DWI
court included in our review.
5

Most evaluations reported some information on criminal justice system involvement.
However, the measures and types of information reported varied. For example, some
evaluations reported arrests, others convictions; some reported the average number of
prior events—either arrest or conviction—while others reported the percent of participants
with at least one event.

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Appendix IV: Overview of Drug Court
Program Characteristics and Participants

reported that 9 percent of participants had no prior felony convictions and
56 percent had been previously incarcerated.

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Appendix V: Drug Court Programs Are
Associated with Recidivism Reductions

Appendix V: Drug Court Programs Are
Associated with Recidivism Reductions
In most of the evaluations we reviewed, adult drug court programs led to
statistically significant recidivism reductions during periods of time that
generally corresponded to the length of the drug court program—that is,
within-program.1 For the remaining programs, evaluations showed no
significant differences in recidivism. Our analysis of the evaluations
showed lower percentages of drug court program participants than
comparison group members were rearrested or reconvicted. Program
participants also had fewer recidivism events—that is, incidents of
rearrests or reconvictions—and a longer time until rearrest or
reconviction than comparison group participants. Recidivism reductions
were observed for any felony offense and for drug offenses, whether they
were felonies or misdemeanors. However, the evaluations did not provide
conclusive evidence that specific drug court program components, such as
the judge’s characteristics or behavior, the amount of treatment received,
the level of supervision provided, and the sanctions for noncompliance
with program requirements, affect participants’ within-program recidivism.
In most of the programs that reported post-program data, recidivism
reductions occurred for some period of time after participants completed
the drug court program.

Drug Court Programs
Led to WithinProgram Recidivism
Reductions

The 27 evaluations we reviewed provided within-program recidivism
comparisons between drug court program participants and an appropriate
control or comparison group of non-drug court defendants in 23 different
drug court programs. Regardless of the type of comparison group used,
within-program recidivism reductions occurred for various measures of
recidivism, such as rearrests and reconvictions, and prevailed across
different types of offenses.2 Less clear, however, was the effect that certain
drug court program components, such as treatment options or sanctions,
had on participants’ recidivism outcomes.

We use within-program to refer to the period of time that all individuals who are enrolled
are expected to be participating in the drug court program.
2

Appendix II presents details on the research designs and comparison groups used in the
evaluations we reviewed.

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Appendix V: Drug Court Programs Are
Associated with Recidivism Reductions

Drug Court Programs Were
Associated with Lower
Rearrest Rates for
Program Participants

Drug court programs included in our review were associated with
reductions in overall rearrest rates—that is, the percentage of a group
arrested for any new offense (felony or misdemeanor) in a given period of
time. Thirteen drug court programs reported overall rearrest data.3 Ten of
these found statistically significant reductions in overall rearrest rates for
drug court program participants.4 Across studies showing rearrest
reductions, rates of drug court program participants generally ranged from
about 10 to 30 percentage points below those of the comparison group.
Table 7 shows these differences in rearrest rates by the length of the time
frame covered.

The evaluations we reviewed provided comparative arrest data for drug court program
participants and comparison group members for 13 drug court programs. In 1 drug court
program—the D.C. Superior Court—data were available for two dockets, or types of drug
court program interventions, to which defendants were assigned.
4

Rearrests, as well as reconvictions, do not measure all re-offending, as every offense or
violation does not lead to an arrest.

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Appendix V: Drug Court Programs Are
Associated with Recidivism Reductions

Table 7: Differences in Overall Rearrest Rates between Drug Court Program Participants and Comparison Group Members
Percentage point difference, time frame
covered
Comparison group used in program
evaluation

Up to 1 year after
entry

Baltimore City Drug Treatment Court

Randomly assigned similar defendants

-16%

Breaking the Cycle Program,
b
Birmingham

Historical—arrestees

-35

Historical—arrestees

-15

-8

-19

Drug court program

Up to 2 years after
entry

Significant reported reductions

Breaking the Cycle Program, Tacoma

D.C. Superior Court Drug Intervention
Program, sanctions docket

Randomly assigned similar defendants

Douglas County Drug Court

Contemporaneous—traditionally
c
adjudicated offenders

Jackson County Drug Court

Historical—arrestees

Kentucky Drug Court Programs

Contemporaneous—assessed
offenders, combined felony and
misdemeanor charge or conviction

-17

Los Angeles County Drug Court
Program

Contemporaneous—probationers

-27

Maricopa County First Time Drug
Offender Program

Randomly assigned similar
probationers—results for combined
groups

Orange County Drug Court Program

Contemporaneous—probationers

-1

-10

-15%

-20

-4

-11 (3 yrs)

Nonsignificant reported differences
Breaking the Cycle Program,
b
Jacksonville

Historical—arrestees

D.C. Superior Court Drug Intervention
Program, treatment docket

Randomly assigned similar defendants

Escambia County Drug Court

Historical—arrestees

7
-1
-10

Source: GAO analysis of drug court program evaluations.

Note: When the difference is negative, that indicates that a drug court program reduced rearrests;
when it is positive, that indicates that drug court program participants had higher rearrest rates than
their comparison group. Nonsignificant differences may be positive or negative, but the absence of a
statistical difference is interpreted to mean that there is no difference in recidivism between the drug
court program and comparison group.
a

The difference was reported to be statistically significant.

According to the principal researcher of the evaluation, the Breaking the Cycle program is technically
not considered to be a drug court program. However, we included the program in our review because
it incorporates several of the basic drug court program components, such as drug testing and access
to treatment services.
c

While these defendants consisted primarily of those arrested during the time the drug court program
was in operation (a contemporaneous comparison), some individuals who were arrested in the 3
months prior to the start of the drug court program were included.

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Appendix V: Drug Court Programs Are
Associated with Recidivism Reductions

Not All Drug Court Programs
Reduced Recidivism for All
Offenses

In two drug court programs (Breaking the Cycle program in Jacksonville
and the D.C. Superior Court treatment docket), the program did not lead
to significant differences in overall within-program recidivism. The
absence of a significant difference suggests that these drug court programs
did not necessarily lead to recidivism reductions. In one of these programs
(the D.C. Superior Court), two types of drug court program interventions
were examined—(1) a treatment docket, consisting of an intensive
treatment-only intervention and (2) a sanctions docket, consisting of an
intervention that combined referrals to treatment with graduated
sanctions. The evaluation showed statistically significant reduction in
rearrests for the sanctions docket. However, results for the treatment
docket (treatment alone) were not statistically significant. A third drug
court program in Escambia County showed mixed results. The drug court
program showed no differences for overall rearrest rates (both felonies
and misdemeanors) but showed a significant reduction in felony rearrest
rates.

Drug Court Programs Were
Associated with Lower
Reconviction Rates for
Program Participants

The evaluations we reviewed showed lower reconviction rates—the
percentage of a group convicted for a new offense in a given period of
time—for drug court program participants than for comparison group
members.5 Almost all of the programs (10 of 12) with these data reported a
statistically significant reduction in reconviction rates for drug court
program participants in one of the time frames covered. The two programs
that did not show statistically significant reductions in reported results in
a direction of reconviction reduction, but not at a statistically significant
level. Table 8 displays the differences in reconviction rates between drug
court participants and comparison group members after up to 1 year and
after 2 to 3 years of entry into their respective programs.

The evaluations we reviewed measured reconviction rates during periods of up to 3 years
after entry into either the drug court program or the comparison group.

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Appendix V: Drug Court Programs Are
Associated with Recidivism Reductions

Table 8: Differences in Reconviction Rates between Drug Court Program Participants and Comparison Group Members
Percentage point difference, time frame
covered
Comparison group used
in program evaluation

Drug court program

Up to 1 year
after entry

2 to 3 years
after entry

-9%

-15% (3 yrs)

-10

-14 (3 yrs)

-8

Significant reported reductions
Bronx Treatment Court

Historical—eligible arrestees
a

Brooklyn Treatment Court

Contemporaneous—eligible arrestees

Douglas County Drug Court

Contemporaneous—traditionally adjudicated
c
offenders

Kentucky Drug Court Programs

Contemporaneous—assessed offenders,
combined felony and misdemeanor charge
or conviction

-15

-5

Maricopa County First Time Drug
Offender Program

Randomly assigned similar probationers—
results for combined groups

-3

-6

Historical—eligible arrestees

-21

-13 (3 yrs)

Contemporaneous—eligible arrestees who
were not arraigned before a judge
supportive of the program

-10

-10 (3 yrs)

Suffolk County Drug Treatment
a
Court

Historical—eligible arrestees

-21

-25 (3 yrs)

Syracuse Community Treatment
a
Court

Historical—eligible arrestees

-16

-14 (2 yrs)

Washington State Drug Court
Program, five counties combined

Historical—arrestees

Queens Treatment Court

Rochester Drug Treatment Court

b
b

-6

Nonsignificant reported reductions
Baltimore City Drug Treatment
Court

Randomly assigned similar defendants

Washington State Drug Court
Program, King County

Historical—arrestees

-5
-2

Source: GAO analysis of drug court program evaluations.

Note: When the difference is negative, that indicates that a drug court program reduced reconvictions;
when it is positive, that indicates that drug court program participants had higher reconviction rates
than the comparison group members. Nonsignificant differences may be positive or negative, but the
absence of a statistical difference is interpreted to mean that there is no difference in recidivism
between the drug court program and comparison group.
a
The data for these six drug court programs were provided from one multisite evaluation of New York
state drug court programs.
b

The difference was reported to be statistically significant.

While these defendants consisted primarily of those arrested during the time the drug court program
was in operation (a contemporaneous comparison), some individuals who were arrested in the 3
months prior to the start of the drug court program were included.

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Appendix V: Drug Court Programs Are
Associated with Recidivism Reductions

The significant differences in reconviction rates between drug court
participants and comparison group members ranged from 8 to
21 percentage points within 1 year of entry into the drug court program.
For the eight drug court programs in which follow-up data were provided
for more than 1 year, statistically significant differences in reconviction
rates ranged from between 5 and 25 percentage points. In five of these
drug court programs, the differences in reconvictions generally increased
or remained about the same as the length of the follow-up period
increased.

Drug Court Participants
Had Fewer Recidivism
Events and Longer Times
to First Recidivism Event
than Comparison Group
Members Did

Consistent with reducing the percentage of participants rearrested or
reconvicted within a given period, drug court program effects may occur
by reducing the number of recidivism events—the number of arrests or
convictions within a particular period—that participants commit and by
increasing the time until participants commit an offense leading to an
arrest or reconviction. In 8 of 12 programs, drug court participants had
fewer rearrests and in 7 of 9 programs they had fewer reconvictions than
comparison group members. Per 100 drug court program and comparison
group participants, drug court program participants had between 9 and
90 fewer arrests during the program, or between 18 and 89 fewer
convictions during the program, depending on the recidivism measure
reported.
Drug court program participants also generally had longer times to first
arrest or conviction than comparison group members. In 11 of
16 programs in which the time to first event was reported, drug court
program participants had longer times to the first recidivism event.

Recidivism Reductions
Were Observed for
Different Offense Types

Evidence showed recidivism reductions for different types of offenses,
specifically for felonies and drug offenses, which may indicate decreased
involvement in substance abuse. In almost all (9 of 12) of the programs
that reported data on felony offense recidivism rates (either rearrest or
reconviction), drug court participants had lower felony recidivism rates or
fewer recidivism events. Similarly, in 11 of 14 of the programs that
reported data on drug offense recidivism, drug court participants were
either rearrested or reconvicted for drug offenses at lower rates.
One drug court program that found no significant reduction in rearrests
did find a reduction in specific offense types. Specifically, the evaluation
of the drug court program in Escambia County found that there were no
significant differences in overall rearrests between drug court participants

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Appendix V: Drug Court Programs Are
Associated with Recidivism Reductions

and comparison group members within 2 years. However, the evaluation
found significant reductions in felony rearrests that amounted to a 28percentage point reduction in felony rearrest rates for drug court program
participants. Because of relatively low participation rates, the researchers
cautioned against interpreting such a large reduction in felony rearrests as
indicative of the amount of a reduction that could be expected from the
drug court program were it to be implemented for a larger numbers of
defendants.

Drug Court Program
Components Were
Infrequently Evaluated and
Results Were Inconclusive

A limited number of evaluations reported information about whether
specific drug court program components affect participants’ recidivism,
and their results were mixed. Drug court program judges, the treatment
programs prescribed for participants, and the sanctions used to enforce
compliance with drug court program procedures are three of the basic
components of drug court programs. Two evaluations that we reviewed
provided data on the effects of treatment and supervision on drug court
program participants’ within-program recidivism outcomes.

Effects of the Role of the Judge

None of the evaluations we reviewed explicitly studied the effect of the
judge—considered to be a critical component of a drug court program—
on participants’ within-program recidivism.

Effects of Substance Abuse
Treatment and Sanctions
Imposed

In evaluations of two drug court programs, the effects of two basic
components of drug courts—substance abuse treatment and sanctions—
were assessed, and their results varied. The specific types of substance
abuse treatment provided to participants differ among programs. In
general, treatment, depending on the needs of the participant, can include
detoxification, individual and group counseling on an outpatient basis,
substance use prevention education, as well as other health, educational,
vocational, or medical services. Similarly, the types and severity of
sanctions that judges use to enforce compliance with program
requirements vary. These sanctions can include writing an essay,
observing drug court proceedings for several days from the jury box,
community service, or short jail stays. Drug court programs may use a
graduated sanctions approach, where successive infractions are met with
increasingly severe sanctions. In other programs, judges may have
discretion to apply sanctions, as needed, according to the specifics of the
case.
To assess the effect of treatment, two evaluations examined recidivism
differences between drug court program participants who attended more
treatment sessions than other participants. In one of the two evaluations

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Appendix V: Drug Court Programs Are
Associated with Recidivism Reductions

that provided the strongest designs for measuring treatment effects—the
evaluation of the Baltimore City Drug Treatment Court—treatment
contributed to reductions in recidivism. However, in the other—the
evaluation of the D.C. Superior Court treatment docket—there were no
differences between the treatment docket and the control group, who
were assigned to a standard docket, consisting of some level of
supervision, monitoring, and access to services.6 In both of these
evaluations, drug court program participants and control group members
participated in treatment, but the drug court program participants
received more treatment and were engaged in a more structured treatment
regime than were control group members.
Findings from these two evaluations also indicate that treatment
requirements combined with supervision and sanctioning contribute the
most to recidivism reductions. While the evaluation of the Baltimore City
Drug Treatment Court measured a distinct difference between those who
participated more heavily in treatment, it also found that those who
received treatment combined with supervision had the lowest recidivism
rates. The D.C. Superior Court sanctions docket, which also combined
judicial supervision with treatment, specifically engaged participants in a
program in which judges applied an established set of graduated sanctions
for failing to comply with drug court program requirements. The sanctions
docket led to fewer rearrests for participants as compared with the control
group assigned to the standard docket. The Baltimore City and D.C.
Superior Court sanctions docket results support the contention that
treatment requirements that are combined with supervision and
sanctioning contribute the most to recidivism reductions.

The evaluation notes that recidivism analysis does not test the effect of a strong treatment
program because the treatment docket experienced substantial operational problems,
including closure because of building structural problems and financial problems that
precluded certain types of services from being delivered.

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Appendix V: Drug Court Programs Are
Associated with Recidivism Reductions

Limited Evidence
Indicates That
Recidivism
Reductions Endure

While fewer evaluations reported post-program, rather than withinprogram, recidivism results, those that did indicate that recidivism
reductions endure beyond the time that participants are engaged in the
program.7 Evaluations we reviewed reported post-program recidivism for
longer periods for 17 drug court programs. In 13 of these 17 programs,
drug court program participants had lower rearrest or reconviction rates
than comparison group members. One evaluation of 6 programs defined
explicit post-program periods of about 1 year, and drug court program
participants had lower recidivism than comparison group members of 5 of
the 6 programs. Among drug court program participants, graduates had
lower post-program recidivism than dropouts.

Lower Rearrest and
Reconviction Rates

Significantly lower rearrest and reconviction rates were reported for
participants in 13 of the 17 drug court programs that reported these data.
As shown in table 9, for 6 drug court programs reporting significant
reductions, the differences in rearrest rates between drug court program
participants and comparison group members ranged between 4 to 20
percentage points. The evaluation of the Multnomah County drug court
program reported only the mean number of arrests (recidivism events),
but it also showed post-program reduction in recidivism using this
measure. For the 9 drug court programs reporting significant reductions,
the differences in reconviction rates between drug court participants and
comparison group members ranged from 5 to 25 percentage points.

We generally use the term post-program to refer to some period of time after drug court
participants and comparison group members completed their respective programs.
However, for some drug court programs, the evaluations measured recidivism for a period
after participants left the program. These represent explicit post-program periods. Postprogram recidivism outcomes were generally observed for no longer than 1 year. Hence, it
is not possible to determine whether the differences in recidivism observed between drug
court program participants and comparison groups would persist.

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Appendix V: Drug Court Programs Are
Associated with Recidivism Reductions

Table 9: Differences in Rearrest and Reconviction Rates, over Longer Time Periods, between Drug Court Program
Participants and Comparison Group Members
Recidivism measure, percentage point difference
Time frame
Rearrested covered after entry

Drug court program

Time frame
Reconvicted covered after entry

Significant reported reductions
Baltimore City Drug Treatment Court
Bronx Treatment Court

-15

2 years

b
b

Brooklyn Treatment Court

Up to 4 years

2 years

-4

1 year post-program

-5

1 year post-program

-11

3 years

-6

3 years

-0.94

2 years

-10

1 year post program
-13

Up to 4 years

-10

Up to 4 years

-25

Up to 4 years

-14

Up to 4 years

-6

3 years

2 years post
program

-2

3 years

North Carolina Drug Treatment Court
b

Queens Treatment Court

b
b

Syracuse Community Treatment Court

Maricopa County First Time Drug Offender
Program

Suffolk County Drug Treatment Court

Up to 4 years

-14
-20

Kentucky Drug Court Programs

Rochester Drug Treatment Court

Jackson County Drug Court

Multnomah County STOP Drug Diversion
c
Program

-15

Washington State Drug Court Program, five
counties combined
Nonsignificant reported differences or significant increase
Clark County Drug Court
Escambia County Drug Court

Southern San Mateo County Drug Court

-10

2 years

Washington State Drug Court Program, King
County
Source: GAO analysis of drug court program evaluations.

Note: When the difference is negative, that indicates that a drug court program reduced recidivism;
when it is positive, that indicates that drug court program participants had higher recidivism rates than
members of their comparison group.
a

The difference was reported to be statistically significant.

The data for these six drug court programs were provided from one multisite evaluation of New York
state drug court programs.
c

The Multnomah County results show differences in the average number of arrests only.

Escambia County drug court showed a significant reduction in felony rearrest rates but showed no
significant difference for overall rearrest rates (both felonies and misdemeanors).

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Appendix V: Drug Court Programs Are
Associated with Recidivism Reductions

Evidence that a gap in post-program recidivism can increase over time
comes from the evaluation of the Maricopa County drug court program. In
Maricopa County, there were no reported differences in recidivism
(specifically rearrest rates) during the 1-year within-program time frame.
However, a 3-year follow-up evaluation found a significant (11 percentage
point) difference in rearrest rates between the drug court program
participants and control group members. The difference arose largely from
an increase in the percentage of control group members that had been
rearrested by the end of the 3-year follow-up; 32 percent of the control
group were rearrested by 1 year, but by 3 years, 44 percent were
rearrested. For the drug court participants, 31 percent had been rearrested
at the end of 1 year, but only an additional 2 percent of the sample were
rearrested within 3 years.

Recidivism Reductions in
Explicit Post-Program
Periods

For the six programs with explicit post-program periods, participants had
significantly lower recidivism than comparison group members in all but
one program, as shown in table 10.

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Appendix V: Drug Court Programs Are
Associated with Recidivism Reductions

Table 10: Post-Program Differences in Recidivism in Six New York State Drug Court Programs
New York state drug court program

Comparison group used in evaluation

Percentage point difference in
recidivism, 1-year post-program

Significant reported reductions
Bronx Treatment Court

Historical arrestees: eligible defendants
arrested in the Bronx prior to the start of the
drug court program.

Brooklyn Treatment Court

Queens Treatment Court

Rochester Drug Treatment Court

Suffolk County Drug Treatment Court

- 13%

Contemporaneous: eligible drug felony
defendants arrested in Brooklyn but not
screened in the drug court, primarily
because they were arrested within one of
the two geographic zones that were
ineligible to send defendants to the drug
court program.

-6

Historical arrestees: eligible defendants
arrested in Queens in the year prior to the
drug court program’s implementation.

-13

Contemporaneous arrestees: eligible
defendants arrested in Rochester during
the same period of time as the drug court
was in operation but who were not
arraigned before a judge supportive of the
program.

-7

Historical arrestees: eligible defendants
arrested in Suffolk County in the year prior
to the start of the drug court program.

-9

Historical arrestees: eligible defendants
arrested in Syracuse City in the year prior
to the start of the drug court program.

-7

Nonsignificant reported reduction
Syracuse Community Treatment Court

Source: GAO analysis of drug court program evaluations.
a

Significant at at least the 1 percent level.

Significant at the 5 percent level.

In five of the six New York state drug court programs, drug court
participants had significantly lower post-program recidivism rates than did
their comparison group members. The differences in recidivism, measured
by the percentage with a new arrest leading to a conviction for 1 year after
drug court participants left the program, ranged from 6 to 13 percentage
points, as shown in table 10. These findings indicate that for some
programs at least, drug court programs can be effective at reducing
criminal behavior while participants are engaged in the program and after
they leave the program. The evaluation of these drug court programs
reports that there is evidence that the effects of drug court programs on
recidivism do not diminish over time, but because the post-program period

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Appendix V: Drug Court Programs Are
Associated with Recidivism Reductions

was only 1 year, that improved understanding of the longer-run effects of
drug courts on recidivism would benefit from additional research that
extends the post-program follow-up time frames.

Graduates Had Lower
Post-Program Recidivism
than Dropouts

Several evaluations compared post-program recidivism outcomes for drug
court program graduates with those of dropouts—those participants who
were terminated from the program either by their withdrawal or by
sanctioning. These evaluations show that the post-program recidivism
differences observed between all drug court program and comparison
group participants arise primarily from the large recidivism differences
between drug court program graduates and dropouts. Evaluations that
reported these comparisons showed large differences in the recidivism
rates of drug court program graduates compared with both dropouts and
comparison group members. For example, in three New York state drug
court programs, dropouts were four to seven times more likely to be
reconvicted than graduates. Specifically, in the Bronx Treatment Court,
29 percent of dropouts were reconvicted during the first year after the
program as compared with only 4 percent of graduates. In addition, the
post-program recidivism rates of dropouts were generally no different
from (or in some cases greater than) the recidivism rates of comparison
group members.

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Appendix VI: Limited and Mixed Evidence on
Drug Court Programs’ Impacts on Substance
Use Relapse

Appendix VI: Limited and Mixed Evidence on
Drug Court Programs’ Impacts on Substance
Use Relapse
Evidence about the effectiveness of drug court programs in reducing
participants’ substance use relapse is limited and mixed. The evidence on
substance use relapse outcomes is limited to data available from eight
drug court programs included in our review. The data include drug test
results and self-reported drug use; both measures were reported for some
programs. Drug test results generally showed significant reductions in use
during participation in the program, while self-reported results generally
showed no significant reductions in use.

Limited Evidence on
Drug Court Programs’
Impact on Substance
Use Relapse

The evidence on substance use relapse outcomes is limited to data
available from eight drug court programs.1 Evaluations in these eight drug
court programs used two different measures of substance use—drug test
results and self-reported use—to compare relapse between participants
and comparison group members. Three of these programs used both
measures to assess relapse. Table 11 shows the comparison group used in
the programs’ evaluation and the results for the eight drug court programs
that presented substance use relapse data, grouped by the type of drug use
measure used.

Some other evaluations we reviewed provided descriptive data on drug court program
participants’ substance use while they were engaged in the drug court program, but these
evaluations did not assess substance use relapse as an outcome by comparing the
outcomes of participants against those of a comparison group.

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Appendix VI: Limited and Mixed Evidence on
Drug Court Programs’ Impacts on Substance
Use Relapse

Table 11: Substance Use Relapse Results, by Different Measures of Use, for Programs GAO Reviewed
Drug court program

Comparison group used in
evaluation of program

Results of substance use relapse

Drug tests
Chester County Drug Court

Historical—probationers

Maricopa County First Time Drug Offender
Program

All individuals identified as eligible for the
drug court program were randomly
assigned to one of three study groups at
the time of their initial probation
assignment. The three study groups were:

Reduction within-program: There were
significantly lower rates of positive drug test
results for drug court program participants.

No reduction within-program: Among all
drug court and probation control group
members, there were no significant
differences in the percent that tested
positive for any drug. However, significantly
lower percentages of drug court
(1) probation with no testing;
participants tested positive for cocaine.
(2) probation with low-rate (monthly) drug
Significantly higher percentages of drug
testing; and
court participants tested positive for
(3) probation with high-rate (biweekly) drug marijuana, valium, and alcohol.
testing.

Self-reported drug use
Breaking the Cycle Program, Birmingham

Historical—arrestees

Reduction within-program: Participants
reported lower use of any drug during the
past 30 days and significantly lower use of
stronger drugs (such as cocaine and
heroin).

Breaking the Cycle Program, Jacksonville

Historical—arrestees

Reduction within-program: Participants
reported significantly lower use during the
past 30 days of any drug, lower heavy drug
use (defined as 16 or more days of illegal
drug use), and lower marijuana use. They
reported no differences in use of stronger
drugs (such as cocaine).

Breaking the Cycle Program, Tacoma

Historical—arrestees

No reduction within-program: There was
no difference in self-reported drug use on
rates or types of drugs.

Randomly assigned eligible defendants

Reduction within-program: Drug tests
were taken during the final month of the
program—that is, within-program. Twentyseven percent of drug court participants
tested drug-free in all drug tests compared
with 11 percent of the control group. Fiftythree percent of drug court participants had
a “bad test outcome” (negative result,
missed test, or tampered result) as
compared with 71 percent of the control
group.

Both drug tests and self-reported use
D.C. Superior Court Drug Intervention
Program, sanctions docket

No reduction post-program: There were
no differences in self-reported drug use that
occurred during the year after sentencing.

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Appendix VI: Limited and Mixed Evidence on
Drug Court Programs’ Impacts on Substance
Use Relapse

Comparison group used in
evaluation of program

Drug court program
D.C. Superior Court Drug Intervention
Program, treatment docket

Randomly assigned eligible defendants

Results of substance use relapse
Reduction within-program: Drug tests
were taken during the final month of the
program. Twenty-two percent of drug court
participants tested drug-free in all drug
tests as compared with 11 percent of the
control group. Also, 64 percent of the drug
court participants had “bad test outcome”
(negative result, missed test, or tampered
result) as compared with 71 percent of the
control group.
No reduction post-program: There were
no differences in self-reported drug use that
occurred during the year after sentencing.

New Castle County Drug Court Program

Drug court program participants who were
randomly assigned to biweekly versus “as
needed” judicial status hearings

Reduction within-program for
subgroups: There were significant
reductions in positive drug test results for
participants with mental health problems
and prior treatment who were assigned to
the biweekly condition compared with those
assigned to the “as-needed” condition.
There were significant reductions in
positive test results for those without
mental health problems assigned to the
“as-needed” condition, but not to the
biweekly condition. However, there were no
overall differences either in drug tests or
self-reported drug use between groups
assigned to biweekly or “as-needed”
hearings.

Source: GAO analysis of drug court program evaluations.

All of the drug test results on substance use relapse were limited to those
obtained when participants were still engaged in the drug court program.
After drug court program participants exit the control of the criminal
justice system, researchers must obtain participants’ voluntary consent to
obtain substance use relapse data, regardless of whether the data are selfreported or based upon urinalysis or other testing methods.2

According to researchers, collecting these data can be expensive. Also, given likely
differences between those who might volunteer and those who would decline, the collected
data might have limited value.

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Appendix VI: Limited and Mixed Evidence on
Drug Court Programs’ Impacts on Substance
Use Relapse

Evidence on Drug
Court Programs’
Impact on Substance
Use Relapse Is Mixed

The results on substance use relapse are mixed. Four of the five drug court
programs that used drug test results reported reductions in use. However,
self-reported data on substance use relapse show contradictory results.
In both of the D.C. Superior Court dockets, prior to sentencing, drug court
program participants had better drug test results than did defendants who
had been randomly assigned to the control group. Similarly, in the Chester
County Drug Court, within-program drug relapse was observed using drug
test results. Drug court program participants had fewer positive urinalysis
results than did a comparison group of eligible offenders who had been
placed on probation in the 10 months prior to the implementation of the
drug court program. These results indicate decreased relapse among
participants despite the fact that drug court program participants were
tested more frequently than were the members of the comparison group.
However, in Maricopa County, there were no significant differences in the
percentage of drug court participants and the combined control groups
that tested positive.
One evaluation we reviewed provided limited evidence that judicial status
hearings reduce within-program substance use for certain types of drug
court program participants. This evaluation, an experiment in a drug court
program in New Castle County, randomly assigned eligible drug court
program defendants to one of two forms of judicial status hearing
conditions: (1) biweekly, regularly scheduled status hearings or (2) status
hearings scheduled on an as-needed basis. During the 14-week drug court
program, participants with antisocial personality disorder (APD) and those
who had prior drug treatment episodes had significantly lower levels of
substance use—as measured by drug test results—when they were
assigned to regularly scheduled biweekly judicial status hearings as
compared with when they were assigned to status hearings on an asneeded basis.3
Four of the six programs with self-reported drug use results reported no
significant reductions in use. For example, after sentencing, neither of the
D.C. Superior Court dockets’ participants reported lower rates of
substance use. Alternatively, in two of the three Breaking the Cycle
programs, participants reported lower rates of substance use than did

Preliminary data from replication experiments confirmed the results of the original
experiment, in that the researchers found evidence of the interaction between the mental
health status of participants and biweekly status hearings.

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Appendix VI: Limited and Mixed Evidence on
Drug Court Programs’ Impacts on Substance
Use Relapse

comparison group members. These differences in self-reported substance
use persisted even after the researchers controlled for sample differences
and selection. The use of self-reported data presents challenges related to
underreporting that we have discussed in a prior report.4

For more information, please see GAO, Drug Use Measurement: Strengths, Limitations,
and Recommendations for Improvement, GAO/PEMD-93-18 (Washington, D.C.: June 25,
1993).

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Appendix VII: Evidence Is Mixed about the
Factors That Predict Program Completion

Appendix VII: Evidence Is Mixed about the
Factors That Predict Program Completion
As discussed in appendix V, participants who completed the drug court
program (that is, graduates) had much lower recidivism rates than those
who dropped out. Further, the recidivism rates for drug court program
dropouts are comparable to the rates of comparison group members.
Completion rates—an indicator of the extent to which participants
successfully complete their drug court program requirements—for
participants in selected programs we reviewed ranged from about 30
percent to about 70 percent.1
In evaluations of 16 drug court programs in which completion was
assessed, one factor—drug court program participants’ compliance with
program procedures—was consistently associated with program
completion. These program procedures include attending treatment
sessions, producing drug-free urinalysis test results, and appearing at
status hearings. No other program factor, such as the severity of the
sanction that would be imposed if participants failed to complete the
program or the manner in which judges conducted status hearings,
predicted participants’ program completion. Several characteristics of the
drug court program participants themselves were also associated with an
increased likelihood of program completion. These characteristics, while
not assessed in all of the programs, include lower levels of prior
involvement in the criminal justice system, and age, as older participants
were more likely to complete drug court programs than younger ones.

Program Completion
Rates Vary

Completion rates ranged from 27 percent to 66 percent for 16 drug court
programs included in evaluations that assessed program completion.
These rates, while consistent with rates reported in other reviews of
multiple drug court programs, are not directly comparable because drug
court programs have different program completion requirements, the rates
were measured over varying time periods, and study designs can affect the
completion measures. Participants are not only required to attend
treatment, but also to appear in court on a regular basis and follow other
rules that are specific to the drug court program. These rules can involve,
but are not limited to, policies on drug testing, case manager or probation
officer visits, school or job attendance, support groups, and graduation

Completion rates represent the individuals who completed or were favorably discharged
from a drug court program as a percentage of the total number admitted and not still
enrolled.

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Appendix VII: Evidence Is Mixed about the
Factors That Predict Program Completion

requirements. Table 12 shows completion rates for the drug court
programs whose evaluations assessed program completion.
Table 12: Completion Rates for Selected Drug Court Programs Included in GAO’s
Review
Drug court program
Bakersfield Municipal Drug Court
Bronx Treatment Court

Completion rate
36%
44

Brooklyn Treatment Court
(Rempel and others, 2003)

(Rempel and DeStefano, 2001)

Broward County Drug Court
(Schiff and Terry, 1997)

(Senjo and Leip, 2001)

Clark County Drug Court

Creek County Drug Court

Escambia County Drug Court Program
(Peters and Murrin, 2000)

(Peters, Haas, and Murrin, 1999)

(Truitt and others, 2002)

Jackson County Drug Court Program
(Anspach and Ferguson, 2003)

(Truitt and others, 2002)

Multnomah County STOP Drug Diversion Program

New Castle County Drug Court
As-needed hearings

Biweekly hearings

Okaloosa County Drug Court

Orange County Drug Court Program

Queens Treatment Court

St. Mary Parish Drug Court

Suffolk County Drug Treatment Court

Syracuse Community Treatment Court

Source: GAO analysis of drug court program evaluations.
a
Evaluation reports “favorable” status, which includes defendants active in treatment plus those who
graduated.

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Appendix VII: Evidence Is Mixed about the
Factors That Predict Program Completion

As noted earlier, drug court programs vary in their specific program
completion requirements. Similarly, programs may terminate defendants’
program participation for a variety of reasons. Drug court program
participants can be terminated from the program if they are arrested for a
new offense, especially for felony offenses; if they regularly fail to appear
at status hearings or treatment sessions; or if they repeatedly do not
comply with program procedures. Consecutive positive drug test results
do not always lead to program termination; in some programs, this could
lead to a change in the treatment services provided or sanctions.

Program Completion
Is Associated with
Compliance with
Program Procedures

Drug court participants’ compliance with drug court procedures, such as
appearing at treatment sessions and remaining drug-free during the
program, was generally a strong predictor of program completion. The
level of program compliance is typically indicated by the degree to which
participants follow rules and procedures determined by the drug court
program, attend required meetings and treatment sessions, and generally
progress toward recovery. Given that program completion is related to
compliance with drug court procedures, we sought to assess whether the
evaluations included in our review provided conclusive evidence about
specific aspects of compliance that were associated with program
completion. For example, in some drug court programs greater levels of
participation were associated with greater likelihood of completing the
drug court program. Similarly, participants having more within-program
arrests, more instances of warrants for failure to appear, and more
positive drug tests were generally less likely to complete the program than
those having fewer of these.
However, for some of the specific aspects of compliance, the findings
were not consistent across drug court programs and in some cases they
were even contradictory. For example, one evaluation of four drug court
programs (Bakersfield, Creek County, Jackson County, and St. Mary’s
Parish) found an inconsistent relationship between drug test results and
program completion across the four drug court programs. This cross-site
evaluation assessed how various aspects of compliance predicted
completion in each program using the same measures of compliance in
each drug court program. In relation to the association between drug test
results and completion, the evaluation found that in one program (Creek
County) drug test results did not have a significant effect on completion.
In another drug court program (St. Mary’s Parish), drug court program
participants that had no positive drug test results were more likely to
complete the program than were participants who had comparatively
“low” or “moderate” numbers of positive test results, whereas there were

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Appendix VII: Evidence Is Mixed about the
Factors That Predict Program Completion

no differences in program completion between those participants who had
comparatively “high” numbers of positive test results and those who had
no positive test results.2 In the two remaining programs (Bakersfield and
Jackson County), participants with positive test results in the low range
actually had a higher likelihood of completing the program than
participants with no positive test results, while in Jackson County,
participants with positive test results in the high range were less likely
than those with no positive test results to complete the program. This
evaluation suggests that there may not be consistency across every drug
court program in the relationship between drug test results and program
completion.

Initial Engagement of Drug
Court Participants

Some research studies indicate that drug court participants’ first few
weeks in treatment are predictive of success. Early engagement in the
drug court program has been measured by whether participants attended
treatment during the first few weeks after program entry and whether
participants have fewer indications of noncompliance (such as failure to
appear or warrants) during the first month of program participation.
One evaluation of five drug court programs in New York State assessed the
role of participants’ early engagement in the drug court program on their
chances of completing the program.3 It found, consistently among the drug
court programs, that early engagement by participants, measured by
whether the participant absconded from program contact within 30 days
of program entry significantly predicted program completion. Across the
five New York drug court programs, participants that received warrants
within 30 days of program entry were from about three to eight times more
likely to fail to complete the drug court program than were participants
who did not receive a warrant within 30 days of program entry.4

The evaluation classified the percent of positive drug test results into four categories:
(1) zero positive test results; (2) “low,” where the percentage of test results that were
positive ranged from 1 to 8 percent of drug tests; (3) “moderate,” where the percentage of
test results that were positive ranged from 9 to 28 percent of drug tests; and (4) “high,”
where the percentage of test results that were positive ranged from 29 to 100 percent.
3

The drug court programs were in the Bronx, Brooklyn, Queens, Suffolk County, and
Syracuse.
4

As defined in the evaluation of these drug court programs, a judge issues a bench warrant
when a defendant fails to make a scheduled court appearance. Bench warrants can also be
issued if defendants fail to appear for scheduled appointments with case managers or
treatment representatives.

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Appendix VII: Evidence Is Mixed about the
Factors That Predict Program Completion

Further, in the Brooklyn Treatment Court, participants’ compliance with
drug court program procedures early in the program also contributed to
participants’ completing 90 days of drug treatment. Those participants
who disappeared from contact, prompting the issuance of a police
warrant, had lower chances of completing 90 days of treatment than those
participants who did not. Additionally, those participants who attended at
least 1 day of treatment within 30 days of entering the program also had
greater chances of completing 90 days of treatment than those who did not
attend at least 1 day of treatment within the first 30 days of entering the
program.
Other aspects of compliance, such as treatment attendance during the
entire program, appearance at status hearings, within-program arrests, and
failure to appear, were generally but not consistently associated with
completion. For example, the percentage of expected treatment sessions
attended increased the likelihood of completion in five of seven drug court
programs.5 On the other hand, in two of the four drug court programs in
which they were measured, within-program arrests and failure to appear
decreased the likelihood of completion but had no effect in the other two
drug court programs.6 Alternatively, in both drug court programs
(Multnomah and Clark Counties) in which the effects of within-program
sanctions were assessed, an increase in the number of sanctions ordered
led to a decrease in the likelihood of completion.

Effects of Drug Court
Programs’
Components on
Program Completion
Are Mixed

In several drug court programs, the effects of various drug court program
components were examined to determine the factors that predict program
completion. Among the components that were examined were various
consequences of program failure and the role of the judge and judicial
status hearings. In a few drug court programs, efforts were made to
examine the role of individual motivation to participate in drug court
programs. In addition, evaluations of a few drug court programs examined
the role of social factors in predicting program completion. Specifically,

The five in which treatment attendance increased the chances of completion were
(1) Bakersfield, (2) Clark County, (3) Creek County, (4) St. Mary’s Parish, and
(5) Multnomah, while the two in which it did not affect completion were Jackson County
and Broward County.
6

In the Bakersfield and Jackson County drug court programs, these effects were observed,
but in the Creek County and St. Mary’s Parish drug court programs, the effects were not
observed.

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Appendix VII: Evidence Is Mixed about the
Factors That Predict Program Completion

these evaluations assessed variables that measured individual’s
attachments to other individuals and social institutions.

Legal Consequences of
Program Failure

Several drug court program evaluations in our review assessed the effects
of different sanctions, or legal consequences of failure, on program
completion. For example, if a drug court program participant fails to
complete the program, he or she may be sentenced to a predetermined
incarceration alternative. The results of these evaluations were mixed and
not directly comparable.7 For example, in the Brooklyn Treatment Court,
participants with a more serious treatment mandate—that is, those
participants that faced longer jail or incarceration terms if they failed to
comply with program requirements—were more likely to complete the
drug court program than those with a less serious treatment mandate. The
predetermined jail sentences for Brooklyn participants who failed to
complete the program ranged from 6 months to 4½ years, depending on
the severity of the charge (felony or misdemeanor) and prior criminal
history (whether it was a first felony offense or not).
Alternatively, in the drug court program in Suffolk County, the length of
the incarceration sentence faced by those who failed to complete the drug
court program did not contribute to program completion. The
predetermined sentence (minimum length of the most common prison
alternative) in Suffolk County ranged from 6 months to 1 year. The
researchers who conducted the evaluation did not provide an explanation
for these differing effects.8

Drug Court Judge

The judge has been described in the research as a key component of a
drug court program. The presence of consistent judicial monitoring of
participants is also described as a distinguishing component of drug court

A number of variables are used to indicate the amount of legal coercion facing
participants. These include the type and severity of charge leading participants to enter the
drug court program, the length of the incarceration time participants face if they fail the
drug court program (only in Suffolk), jail or prison alternatives (not used in Bronx, Suffolk,
and Syracuse), the “treatment mandate,” which is used in one program (Brooklyn) as a
proxy for jail or prison alternative because there is a fairly uniform sentencing approach
based on the treatment mandate.
8

Rempel, M., and others, The New York State Adult Drug Court Evaluation: Policies,
Participants, and Impacts. New York: Center for Court Innovation, 2003, p. 100.

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Appendix VII: Evidence Is Mixed about the
Factors That Predict Program Completion

programs, compared with other court-based treatment programs, such as
probation. Several evaluations in our review examined the effect of drug
court judges on program completion. Each demonstrated that judges can
play an important role in contributing to participants’ program completion.
However, the effect of the judge on program completion is difficult to
distinguish from the requirement to attend judicial status hearings. For
example, one evaluation of drug court program completion in Broward
County attempted to assess the types of comments that judges made and
the effect of these comments on program completion. Court monitoring
comments made by judges that the researchers classified as supportive
were found to contribute to program completion.9 On the other hand, in
one evaluation of two drug court programs (Clark and Multnomah
Counties), the number of appearances before the drug court judge was
found to increase the likelihood of program completion.
A third evaluation (in New Castle County, Delaware) assessed the
regularity of judicial status hearings on program completion. Participants
were randomly assigned to one of two different forms of judicial status
hearings: (1) biweekly hearings and (2) hearings on an as-needed basis, as
determined by court officials. There were two main findings from this
evaluation (that were also supported by the two replications of the
experiment). First, there was no “direct” effect of the different status
hearing schedules on program completion rates. Second, there was an
interaction between client characteristics and program completion. Drug
court program participants that either had prior treatment experiences or
were diagnosed as having APD were more likely to complete the program
when they were assigned to the regular biweekly status hearings as
compared with when they were assigned to status hearings on an asneeded basis. Conversely participants who were not diagnosed as having
APD or who had no prior treatment experiences were more likely to
complete the program when they were assigned to status hearings on an
as-needed basis, as compared with the biweekly condition.
The results from the New Castle County experiment show that the
regularity of the schedule of status hearings can contribute to program
completion for distinct subpopulations of drug court program participants

Senjo, S. R., and L. A. Leip. “Testing and Developing Theory in Drug Court: A Four-Part
Logit Model to Predict Program Completion,” Criminal Justice Policy Review, vol. 12, no.
1, 2001, p. 82.

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Appendix VII: Evidence Is Mixed about the
Factors That Predict Program Completion

and that there may not be a “one size fits all” approach to scheduling court
appearances for all participants.

Participants Who
Were Older and Had
Less Criminal History
than Other
Participants Were
Most Likely to
Complete Programs

The evaluations of several drug court programs examined some of the
attributes of drug court participants and how those factors were related to
program completion. Attributes such as prior substance abuse treatment,
prior criminal history, type of drug used, demographic characteristics, and
employment and education were assessed. Prior criminal history, whether
measured by the number of arrests or convictions prior to program entry,
and age, as older were generally likely to complete their drug court
programs than were younger participants to complete the program, were
related to program completion.
The other attributes were generally found not to be significant predictors
of completion, although among various minorities of drug court programs
in which they were assessed, they were significant predictors of
completion. For example, prior substance abuse treatment was a
significant predictor of completion in three of seven drug court programs,
but it was not significant in the other four drug court programs. Similarly,
other attributes such as type of drug use, race or ethnicity, gender, or
employment or education level were not observed to consistently predict
completion.
The evaluations that assessed participants’ attributes were correlational—
that is, they that examined the associations among these factors and the
probability of program completion. Although not all of the evaluations
included all of the same factors in their analyses, some general patterns
about the correlates of program completion emerged. Attributes of drug
court program participants that were associated with an increased
likelihood of program completion include the following: (1) lower levels of
prior criminal history; (2) substance use other than cocaine or heroin;
(3) employment or school attendance at the time of program intake, along
with higher levels of education; and (4) age, as older participants were
more likely to complete the programs.10 One evaluation attempted to
measure the effect of motivation and readiness for treatment on program
completion. It found that those participants who were better able to

However, not all of these factors consistently predicted program completion in all drug
court programs in which they were examined.

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Appendix VII: Evidence Is Mixed about the
Factors That Predict Program Completion

recognize their problems, recognize external problems, and were ready for
treatment, were more likely to complete the drug court program.

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Appendix VIII: Evidence from Four
Evaluations Indicates Drug Court Programs’
Positive Net Benefits

Appendix VIII: Evidence from Four
Evaluations Indicates Drug Court Programs’
Positive Net Benefits
Four evaluations in our review included sufficient information about seven
drug court programs’ costs and benefits to estimate their net benefits—
that is, benefits less costs.1 All but one of the evaluations found that drug
court programs were more expensive than conventional case processing.
The costs to operate drug court programs above the costs of providing
conventional case processing services ranged from about $750 to about
$8,500 per participant. However, taking into account the drug court
programs’ benefits, especially the reduced costs of crime associated with
reductions in recidivism, all four evaluations we reviewed reported net
benefits ranging from about $1,000 per participant to about $15,000, mostly
because of reduced victimization. Additionally, these benefits may
underestimate drug court programs’ true benefits because the evaluations
did not include indirect benefits (such as reduced medical costs of treated
participants).

Most Evaluations
Found Drug Court
Programs More
Expensive than
Conventional Case
Processing

All but one of the evaluations we reviewed found drug court programs
more expensive than conventional case processing. A combination of
judicial supervision, monitoring, and treatment services that drug court
programs typically provide to their participants—services in addition to
those provided to offenders who are processed with conventional
procedures receive—result in additional expense to criminal justice
agencies. Table 13 shows the net costs of drug court programs—costs
above normal court costs—including supervision, monitoring, and
treatment, ranging from somewhat less than $800 to about $8,700 per
participant.

Appendix III provides more information about our review of drug court program
evaluations that presented cost data and the criteria we used to assess them.

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Appendix VIII: Evidence from Four
Evaluations Indicates Drug Court Programs’
Positive Net Benefits

Table 13: Reported Costs per Drug Court Program Participant in Four Evaluations
Drug court program

Costs above normal costs

D.C. Superior Court Drug Intervention Program
Treatment docket

$ 8,708

Sanctions docket

3,248

Washington State Drug Court Program

3,892

Breaking the Cycle Program
Tacoma, Wash.

1,461

Jacksonville, Fla.

1,133

Birmingham, Ala.

767

Multnomah County (Ore.) STOP Program

(1,442)

Source: Drug court program evaluations.
a
According to the principal researcher of the evaluation, the Breaking the Cycle program is technically
not considered to be a drug court program. However, we included the program in our review because
it incorporates several of the basic drug court program components, such as drug testing and access
to treatment services.

The Multnomah County drug court program cost about $1,400 less than
normal court procedures. Rather than relying on administrative records
and budgets, the program’s evaluation used a methodology that closely
followed participants through treatment and court adjudication. It
calculated the amount of time that each drug court participant and
comparison group participant spent in different activities, such as
treatment and court hearings. The evaluation found that the judge spent
less time with offenders in the drug court program than in normal court
processing and that this led to the estimated decreased costs.

Drug Court Programs’
Net Benefits Derived
from Reductions in
Recidivism

The monetary benefits of reduced recidivism can be placed in two
categories: (1) reduced future expenditure by criminal justice agencies
and (2) reduced future victimization. Any arrest is a cost to a number of
criminal justice agencies, including police, prosecutors, courts,
corrections departments, and probation agencies. Reducing arrests by
reducing recidivism would benefit these agencies.2 The justice system’s
benefits in the seven drug court programs we reviewed ranged from none
to about $3,800 per participant. Some of the range is due to
methodological differences among the evaluations, but some may be due

A reduction in arrests would result in a benefit to the taxpaying members of society, since
taxpayers fund the criminal justice agencies.

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GAO-05-219 Drug Court Effectiveness

Appendix VIII: Evidence from Four
Evaluations Indicates Drug Court Programs’
Positive Net Benefits

to differences among the communities served by the courts. A reduction in
recidivism also benefits people who might otherwise be victimized. The
costs to potential victims of crime that are thus avoided include direct
monetary costs, such as the value of property that is not stolen and
expenses for health care that are not incurred, and quality-of-life costs,
such as costs for pain and suffering that are not experienced. Benefits to
potential victims reported in the evaluations we reviewed ranged from
about $500 to $24,000 per participant.
The evaluations we reviewed monetized the benefits from averted crime
inconsistently, but the differences in method do not explain the range of
benefits. For example, excluding the cost of pain and suffering from
victimizations that do not occur underestimates the true cost of crime.
However, the two evaluations that did not include these costs—D.C.
Superior Court and Breaking the Cycle—found the highest and lowest per
participant dollar values of reduced recidivism, at $24,000 and $500,
respectively.

All Seven Drug Court
Programs Reported
Positive Net Benefits

Although six of the seven drug court programs were more costly than
conventional case processing, the monetary value of the benefits from
reduced recidivism—to the justice system and potential victims—was
greater than the costs, producing positive net benefits in all seven
programs. The net benefits of the seven drug court programs we reviewed
ranged from about $1,000 to about $15,000 per participant. Table 14
presents benefits to the justice system and to potential victims, the net
costs of the programs (costs of the drug programs above conventional
case processing), and net benefits, or benefits minus net costs.

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GAO-05-219 Drug Court Effectiveness

Appendix VIII: Evidence from Four
Evaluations Indicates Drug Court Programs’
Positive Net Benefits

Table 14: Net Benefits per Participant in Seven Drug Court Programs
Benefits

Drug court program

Justice
system

Net benefits (benefits less costs)

Avoided
potential victim

Costs (net drug court
program costs)

Justice
system

Justice system
plus avoided
potential victims

D.C. Superior Court Drug Intervention Program
a

$ 24,030

$ 8,708

$ 19

6,203

3,248

($ 3,230)

2,973

394

7,324

1,461

(1,067)

6,257

Jacksonville, Fla.

2,900

1,133

(1,133)

1,767

Birmingham, Ala.

1,320

479

767

553

1,032

Multnomah County
(Ore.) STOP Program

2,329

1,301

(1,442)

3,771

5,072

Washington State Drug
Court Program

3,759

3,020

3,891

(132)

2,888

Treatment docket
Sanctions docket

$ 15,322

Breaking the Cycle Program
Tacoma, Wash.

Source: GAO analysis of drug court program evaluations’ reported costs and benefits.
a
The D.C. Superior Court Drug Intervention Program evaluation did not draw conclusions about the
net benefits of the treatment docket because of inconsistencies between self-reported crime and
official arrest records.
b
Benefits to potential victims were derived from survey data and do not include the cost of pain and
suffering.
c

Benefits to the justice system were determined by official records of arrest.

However, as shown in the last two columns of table 14, the financial cost
savings due to reductions in recidivism for the criminal justice agencies
were not always positive. Positive financial cost savings for the criminal
justice agencies were indicated for only two programs—Breaking the
Cycle Program in Birmingham and the drug court program in Multnomah
County.

Net Benefits May
Underestimate the
Programs’ True
Benefits

None of the evaluations included indirect, or secondary, benefits to
society derived from a reduction in participants’ substance abuse. Indirect
benefits might include costs avoided because treated drug addicts did not
use medical services that would otherwise have been required. After
successful drug treatment, such individuals might have fewer periods of
unemployment and might be more productive, earning higher wages. To
the extent that they pay higher taxes as a result, these are benefits to
taxpaying members of society. While these benefits are difficult to quantify
in assessing a drug court program, their absence suggests that reported net
benefits are understated.

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GAO-05-219 Drug Court Effectiveness

Appendix IX: GAO Contacts and Staff
Acknowledgments

Appendix IX: GAO Contacts and Staff
Acknowledgments
GAO Contacts

Laurie E. Ekstrand, (202) 512-8777
William J. Sabol, (202) 512-3464

Acknowledgments

In addition to those named above, Mary Catherine Hult, David P.
Alexander, Michele C. Fejfar, Benjamin A. Bolitzer, Harold J. Brumm, Jr.,
Wayne A. Ekblad, Ann H. Finley, Ronald La Due Lake, Jean L. McSween,
Albert Schmidt, Barry J. Seltser, Douglas M. Sloane, Shana B. Wallace, and
Kathryn G. Young made key contributions to this report.

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GAO-05-219 Drug Court Effectiveness

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