Journal of Urban Health: Bulletin of the New York Academy of Medicine, Vol. 83, No. 5
doi:10.1007/s11524-006-9065-2
* 2006 The New York Academy of Medicine

Sexual Violence Inside Prisons: Rates
of Victimization
Nancy Wolff, Cynthia L. Blitz, Jing Shi, Ronet Bachman,
and Jane A. Siegel
ABSTRACT People in prison are exposed to and experience sexual violence inside
prisons, further exposing them to communicable diseases and trauma. The consequences of sexual violence follow the individual into the community upon release.
This paper estimates the prevalence of sexual victimization within a state prison
system. A total of 6,964 men and 564 women participated in a survey administered
using audio-CASI. Weighted estimates of prevalence were constructed by gender and
facility size. Rates of sexual victimization varied significantly by gender, age,
perpetrator, question wording, and facility. Rates of inmate-on-inmate sexual
victimization in the previous 6 months were highest for female inmates (212 per
1,000), more than four times higher than male rates (43 per 1,000). Abusive sexual
conduct was more likely between inmates and between staff and inmates than
nonconsensual sexual acts. Sexual violence inside prison is an urgent public health
issue needing targeted interventions to prevent and ameliorate its health and social
consequences, which spatially concentrate in poor inner-city areas where these
individuals ultimately return.
KEYWORDS Inmate sexual assault, Prison rape, Staff-on-inmate sexual assault.

INTRODUCTION
Prison is a violent place. One type of violence that is often attributed to prison settings
is sexual victimization.1,2 Sexual victimization includes a range of behaviors from
sexually abusive conduct to nonconsensual sexual assaults3 and has a variety of
severe public health consequences.4 Rape provides an opportunity for spreading
sexually transmitted diseases,5 a matter of particular concern in prisons, where HIV
infection rates are higher than in the general population. Sexual victimization can
foment rage, leading to future violence either inside or outside prison,6,7 as well as
depression and acts of self violence, such as drug use or suicidal ideation and
gestures.5,8,9
Lawsuits by former prisoners who experienced rape and sexual abuse behind
bars compelled Human Rights Watch to investigate the issue; they obtained
testimony from over 200 prisoners in 37 states and published their findings in a
graphic account of the reality of rape in prison.10 This report, entitled BNo Escape:
Wolff, Blitz, and Shi are with the Center for Mental Health Services & Criminal Justice Research,
Rutgers University, New Brunswick, NJ, USA; Bachman is with the Department of Sociology and
Criminal Justice, University of Delaware, Newark, DE, USA; Siegel is with the Department of Criminal
Justice, Rutgers University, Camden, NJ, USA.
Correspondence: Nancy Wolff, PhD, Center for Mental Health Services & Criminal Justice Research,
Rutgers University, 30 College Avenue, New Brunswick, NJ 08901, USA. (E-mail: nwolff@ifh.rutgers.
edu)
835

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WOLFF ET AL.

Male Rape in Prison,^ was the primary impetus for Congress to pass legislation
called The Prison Rape Elimination Act (PREA) of 2003,11 which was structured to
measure the rate of sexual assault inside state prisons as well as to develop
interventions for treating those who were raped and preventing future incidents of
sexual victimization. The current study was funded as part of the PREA and was
designed to measure the prevalence of sexual victimization inside a statewide prison
system.
Research suggests that rates of sexual victimization in prison may be as high as
41% or as low as less than 1%.12 A recent meta-analysis estimates a conservative
Baverage^ prevalence estimate of prison sexual assault at 1.9%.12 While the
estimated rate of victimization varies significantly across studies, the characteristics
of the victims reported in these studies are more similar. First, rates of sexual
coercion are higher than rates of sexual assault or rape, independent of gender.13–17
More specifically, unwanted and sexually suggestive touching of breasts, genitals, or
buttocks is more typical inside prison than the act of rape itself. Second, in the vast
majority of studies, male facilities have been found to have higher rates of sexual
assault compared to female facilities.15–18 Yet the perpetrators of sexual assaults
against female inmates, compared to male inmates, are less likely to involve staff.
Third, younger inmates are at greater risk of sexual victimization, particularly if
they are new arrivals to a facility and are serving their first convictions.13–15,20 This
may explain in part why rates of sexual victimizations vary across facilities within
the same prison system. Facilities with a younger population would be expected to
have higher rates of victimization than those facilities with a more mature and
acculturated prison population. Fourth, inmate-on-inmate sexual victimization has
an interracial bias, with victims most likely being White and sexual aggressors most
likely being Black.2,21 This interracial pattern of victimization has been attributed
to revenge for historical oppression20 and the reversal of racial dominance inside
prison.2
While these patterns of sexual victimization inform interventions to prevent
such violence inside prisons, they do not reliably provide evidence on the prevalence
of the problem, which was one of the major objectives of the PREA legislation.
What is known is that the estimates of the prevalence of sexual victimization inside
correctional settings are sensitive to methodology. Extant studies are based on
different definitions of sexual victimization and diverse sampling designs. Estimates
of the prevalence or incidence of sexual violence are extremely sensitive to
methodology, with larger estimates derived from more specific questions about
sexual victimization.22 The current study provides more accurate estimates of the
prevalence of sexual victimization within a prison population based on the
following advantages:
1. Representativeness: Sample selection, differing facility types, and inmate levels
of non-response severely limit the generalizability of published estimates.
Previous studies have focused largely on a single prison and/or small numbers
of inmates (less than 15% of the population).13,14,19–21,23–27 Hensley et al.19
employed a design in which 100 inmates were randomly selected from three
facilities, with an average refusal rate of 42%. Struckman-Johnson et al.15,16
sampled more facilities and had larger samples but had large (70%) nonresponse rates. Evidence also suggests that prison environments are heterogeneous and the management and operation of prisons, even with similar custody
levels, affect inmates’ behavior differently.28

SEXUAL VIOLENCE INSIDE PRISONS: RATES OF VICTIMIZATION

837

2. Validity: The phrasing of survey questions affects the extent to which
victimization is uncovered. The wording of questions used in previous studies
to elicit information about sexual victimization varies significantly, with some
questions focusing on Bbeing coerced to engage in a sex act or have sexual
contact,^ while others have used questions relying on labels such as Bbeing raped
or sexually assaulted.^ Contemporary rape research has documented that
questions using behavior and context specific terminology generally produce
more valid responses.22,29–31
3. Reliability: Inquiring about sexual victimization invokes feelings of stigma and
shame. Previous studies have relied on face-to-face interviewing or, more
commonly, self-administered pencil and paper surveys to inquire about sexual
victimization in prisons. The literature indicates that computer-assisted selfadministered interviews (CASI), with audio added to assist with literacy
problems, are the most reliable method for eliciting information about
potentially stigmatizing behavior.12,32–39
To our knowledge, this study is the first to explore the prevalence of sexual
victimization within a state prison system. It is also the first to use (1) a full
population sampling design of approximately 20,000 inmates at 13 prisons; (2)
multiple general and specific questions to measure sexual victimization; and (3)
audio-CASI to administer the survey.

METHODS
Sampling
The current study’s population was all inmates housed at 12 adult male prisons and
one female prison operated by a single state (N = 22,231). Excluded from this
group were inmates younger than 18 or in administrative (pre-hearing) custody,
detention, death row, a sex offender treatment facility, or otherwise too sick to
participate in the survey. Also excluded were inmates residing in halfway houses or
off-site at the time of the survey. In all, 19,788 inmates (89% of the entire
population) were eligible to participate.
Respondents were sampled in one of two ways. In all facilities, inmates housed in
the general population (n = 18,956) were invited by the researchers to participate in
a survey about the quality of life inside the prison. Response rates across all
facilities ranged from 26 to 53%, with a mean response rate of 39% (SD: 0.068).
Non-respondents at six facilities reported their reasons for not participating in the
survey. The three most common reasons reported by 848 inmates declining
participation were: BI believe nothing will ever change here^; BI am leaving here
soon^; and BThis is prison. Our quality of life doesn’t matter.^ Four facilities have
specialized administrative segregation units, separating inmates with behavioral
infractions from the general population. These individuals had limited movement
privileges and could only be interviewed face-to-face in a secure but confidential
setting. Of the 832 inmates housed in these units, 10% of the sample was invited to
participate, and 100% agreed to complete the survey through a face-to-face
interview.
A total of 6,964 men (x¯ age = 34.0) and 564 women aged 18 or older
participated in the study (x¯ age = 35.5). Over two-thirds (67.4%) of the female

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WOLFF ET AL.

inmates were nonwhite while 80.5% of the males were nonwhite. These statistics
are equivalent to the general prison population (67.3% of females are nonwhite
with a mean age of 35.4, and 80.1% of the males are nonwhite with a mean age of
34.3). The percent Latino in the survey sample (9.1% female; 15.7% male) was
similar to the population as a whole (10.1% female; 14.9% male).

Procedures
The surveys were conducted at the female facility during the first week of June 2005
and at male facilities from June through August of 2005. The survey was
administered using audio-CASI and was available in English and Spanish. Inmates
responded to a computer-administered questionnaire by using a mouse and
following audio instructions delivered via headphones. Thirty computer stations
were available, and researchers were there to assist participants as needed. The
English version of the CASI survey was generally completed within 60 min while
the Spanish version took approximately 90 min. Of those participating in the
survey, 112 men (1.6%) and 18 (3.2%) women were interviewed directly. The
majority of these respondents (65%) were housed in administrative segregation.
The other face-to-face interviews (35%) were conducted because participants were
intimidated by the computer or were in the infirmary or specialized mental health
unit. Five interviewers conducted the interviews, with the majority (61%)
conducted by two interviewers. All interviewers were trained and followed a
scripted protocol. Face-to-face interviews, conducted only in English, were
completed in roughly 45 min.

Variables and Measures
The questions regarding sexual victimization were adapted from the National
Violence Against Women and Men Surveys40 and appear in the Appendix. Sexual
violence was measured using two general questions for each type of perpetrator
(inmate or staff member). The questions were BHave you been sexually assaulted by
(an inmate or staff member) within the past 6 months?^ and BHave you ever been
sexually assaulted by (an inmate or staff member) on this bid [conviction]?^ Ten
additional questions about specific types of sexual victimization were used [e.g.,
during the past 6 months, has (another inmate or staff member) ever ... touched you,
felt you or grabbed you in a way that you felt was sexually threatening or made you
have sex by using force or threatening to harm you or someone close to you].
The specific sexual assault questions were clustered to reflect definitions of
sexual violence developed by the National Center for Injury Prevention and
Control.41 Sexual violence was defined as nonconsensual sexual acts, which
consisted of forced sex acts, including oral and anal sex, and abusive sexual
contacts, which included intentional touching of specified areas of the body.3 Seven
of the specific questions involving penetration or sexual acts were included in the
category for nonconsensual sexual acts [e.g., has (another inmate or staff member)
ever... made you have oral sex by using force ...]. Three questions were used to
construct abusive sexual contacts [e.g., has (another inmate or staff member) ever
touched you, felt you or grabbed you in a way that felt sexually threatening].
Inmates who responded affirmatively to any one of the ten questions were
considered sexual victims. The survey did not ask questions about consensual sex
between inmates or between staff and inmates.

SEXUAL VIOLENCE INSIDE PRISONS: RATES OF VICTIMIZATION

839

Six-month prevalence of sexual victimization measures the number of people in
the population experiencing sexual victimization within a 6-month period and is
calculated using general and specific questions. Bid-time prevalence of sexual
victimization measures the number of people in the population experiencing a
sexual assault while incarcerated on the current conviction, which is based on the
general question only.
Weights
Weights were constructed to adjust the characteristics of the sampled population to
the full population of inmates at each facility. A two-step weighting strategy was
used.42 The first step (relative weight) adjusted for the sampling design (i.e., the
exclusion of some units within a facility, the variation in the probability of
selection, and proportional representation by facility). The second step (poststratification weight) adjusted the data on the basis of time at facility, race/ethnicity,
and age. The final weight for each strata is the relative weight multiplied by the
post-stratification weight.
Analyses Both weighted and unweighted analyses were conducted. As unweighted
results are not dissimilar to weighted results, only weighted results are presented.
Unless otherwise indicated, the significance level used to assess the validity of the
null hypotheses is p G 0.05.

RESULTS
Characteristics of Survey Respondents
The characteristics of the sample, by gender, appear in Table 1. Female inmates
participating in this study (n = 564) had a mean age of 35.5 years and were mostly
African American (56.5%). By contrast, male inmates (n = 6,964) were a year
younger on average (34.0) and were significantly more likely to be African
American or Hispanic (63.7 and 15.7%, respectively). A greater percentage of
males than females were serving life sentences (7.8% compared to 4.0%,
respectively), and, on average, males had one additional year left on their current
sentence than females (4.0 years compared to 2.8 years, respectively). On average,
male inmates had served more time in prison since the age of 18 than females (8.1
years compared to 4.2 years, respectively). Female inmates, compared to their male
counterparts, were significantly more likely to report having mental health problems
(65.6 vs. 30.0%, respectively), a substance abuse disorder (43.3 vs. 27.1%,
respectively), and a chronic physical condition (58.1 vs. 30.8%, respectively).
Bid-Time Prevalence Rates
Prevalence estimates are based on the reporting of any sexual victimization while
serving time on the current sentence at any facility within the statewide system. Bidtime prevalence rates are calculated using responses from the general assault
question and are delineated by perpetrator (inmate-on-inmate and staff-on-inmate).
The prevalence rate for inmate-on-inmate sexual assault was two times higher for
inmates in female facilities than male facilities (39 per 1,000 vs. 16 per 1,000, with
95% CI 28–50 vs. 13–19), and the comparable staff-on-inmate rate is 1.6 times
higher (53 per 1,000 vs. 34 per 1,000, with 95% CI 41–68 vs. 30–38). Rates of
reported sexual assault by staff were higher than assaults by inmates for both

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TABLE 1. Characteristics of survey respondents, inmates in statewide correctional system, by
gender, 2005

Age*, y
Mean (SD)
Race*, %
White
Black
Other
Ethnicity, %
Latino*
Incarceration characteristics
Time at current facility, mean (SD)
Life sentence*, %
Time left on current sentence a*, mean (SD)
Time incarcerated from age 18*, mean (SD)
Clinical characteristics, %
Mental health problem*
Substance abuse*
Head trauma
Chronic physical condition*

Female (n = 564)

Male (n = 6,964)

35.5 (6.8)

34.0 (7.9)

32.6
56.5
10.9

19.5
63.7
16.8

9.1

15.7

2.3 (3.4)
4.0
2.8 (5.4)
4.2 (3.7)
65.6
43.3
6.6
58.1

2.5 (4.5)
7.8
4.0 (5.7)
8.1 (7.1)
30.0
27.1
7.5
30.8

All estimates are weighted. Mean differences were tested using t-tests and differences in percentages were
tested using chi-square.
a
Time left on current sentence excludes those with a life sentence.
*Statistically significant difference (p G 0.05).

female and male inmates but still within the range of a rare event. Inmates aged 25
or younger, compared to inmates older than 25, were significantly more likely to
report a sexual assault during incarceration by a staff member (54 per 1,000 vs. 30
per 1,000, with 95% CI 43–65 vs. 26–34).
Six-Month Prevalence Rates
The proportion of inmates reporting an incident of sexual victimization within the
6-month period varied by the way the survey question was worded. The prevalence
rates for both inmate-on-inmate and staff-on-inmate sexual victimization were
lower for the (general) question that referred to an incident of Bsexual assault,^
compared to the (specific) questions describing specific types of sexual misconduct
for both female and male inmates (females: 23 vs. 210 per 1,000 (inmate-on-inmate),
25 vs. 75 per 1,000 (staff-on-inmate); males: 16 vs. 38 per 1,000 (inmate-on-inmate),
26 vs. 69 per 1,000 (staff-on-inmate). There were, however, unduplicated positive
responses to the general and specific questions of sexual victimization (i.e.,
individuals may have responded Fyes_ to the general question but Fno_ to the specific
questions, Fno_ to the general question but Fyes_ to the specific questions, or Fyes_ to
both the general and specific questions). Unduplicated positive responses to both
questions, when combined, yielded slightly higher incidence rates for inmate-oninmate and staff-on-inmate sexual victimization than those based solely on the
specific questions for both female (212 vs. 210 per 1,000; 76 vs. 75 per 1,000,
respectively) and male (43 vs. 38 per 1,000; 76 vs. 69 per 1,000, respectively)
inmates. For this reason, in this section we report unduplicated 6-month prevalence
rates based on the combined responses to the general and specific questions.

SEXUAL VIOLENCE INSIDE PRISONS: RATES OF VICTIMIZATION

841

TABLE 2. Six-month prevalence of sexual victimization in statewide correctional system, by
gender, 2005; rates per 1,000 and 95% confidence intervals
Female (n = 564)
rate per 1,000 inmatesa
(95% CI)
Inmate-on-inmate sexual victimization
Any incidents*
Any abusive sexual contact*
Any nonconsensual sex acts*
Staff-on-inmate sexual victimization
Any incidents
Any abusive sexual contact
Any nonconsensual sex acts

Male (n = 6,964)
rate per 1,000 inmatesa
(95% CI)

212 (188–237)
201 (178–224)
32 (23–42)

43 (39–47)
35 (31–38)
15 (12–17)

76 (62–91)
66 (52–80)
17 (10–25)

76 (70–81)
66 (61–71)
19 (16–21)

a
The estimates of FRate per 1,000 inmates_ are based on weighted valid numbers.
*Statistically significant difference between males and females (p G 0.05).

Table 2 provides estimates of weighted 6-month prevalence rates of sexual
violence in a statewide prison system by gender based on the number of inmates in
the sample who reported experiencing sexual victimization in the 6-month period
preceding data collection. Gender-based incidence rates per 1,000 inmates are
distinguished for two general categories of perpetrators (inmate-on-inmate and
staff-on-inmate) and are further broken down by two types of sexual violence:
abusive sexual contacts and nonconsensual sexual acts.
Prevalence rates were highest for female inmates, with 21.2% (212 per 1,000)
reporting an incident of some type of inmate-on-inmate sexual victimization in the
previous 6 months. This rate was four and a half times higher than that estimated
for male inmates (4.3%). Incidents of abusive sexual contact contributed most of
the difference in inmate-on-inmate prevalence rates by gender. Female inmates were
roughly six times more likely to report an incident of abusive sexual contact than
their male counterparts (20.1 vs. 3.5%), while only being twice as likely to report
an incident of a nonconsensual sex act (3.2 vs. 1.5%, respectively). There were no
statistically significant differences between males and females in rates of experiencing staff-on-inmate sexual violence. While female inmates were more likely to be
sexually victimized by other inmates than by staff (21.2 vs. 7.6%), male inmates
were more likely to report an incident of sexual victimization perpetrated by staff
(7.6 vs. 4.3%).
Table 3 displays male prevalence rates for inmate-on-inmate and staff-oninmate sexual victimization by facility size, categorized by inmate population (up to
1,100 inmates, 1,101–1,900 inmates, and more than 1,901 inmates). Prevalence
rates vary by facility, ranging from 30 to 64 per 1,000 for inmate-on-inmate sexual
victimization and 37 to 118 per 1,000 for staff-on-inmate sexual victimization. No
discernible pattern exists by size of facility. Independent of facility size, staff-oninmate rates of sexual victimization were higher than inmate-on-inmate rates and
were significantly higher for four of these facilities (#5,6,10,11).
As can be seen in Table 4, abusive sexual conduct perpetrated by both inmates
and staff was more common than nonconsensual sexual acts. Between inmates, the
rates of abusive sexual conduct were 1.2 to 7 times higher than rates of nonconsensual sexual acts. The variation in 6-month prevalence rates for staff-oninmate abusive sexual conduct compared to nonconsensual sexual acts was also

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WOLFF ET AL.

TABLE 3. Six-month prevalence of sexual victimization reported by male respondents in
statewide correctional system, 2005, n = 6,964; rates per 1,000 and 95% confidence intervals
Inmate-on-inmate rate per
1,000 inmatesa (95% CI)

Staff-on-inmate rate per
1,000 inmatesa (95% CI)

General question (n = 6,736)
16 (13 – 18)
Specific question (n = 6,821)
38 (34 – 41)
Combined questions (n = 6,824)
43 (39 – 47)
Facilities with populations to 1,100
1
64 (45 – 82)
2
47 (21 – 68)
3
31 (10 – 52)
Facilities with populations from 1,101 to 1,900
4
49 (31 – 67)
5
38 (23 – 52)
6
38 (22 – 56)
Facilities with populations over 1,901
7
50 (34 – 68)
8
52 (39 – 65)
9
32 (23 – 42)
10
41 (33 – 49)
11
46 (28 – 62)
12
30 (19 – 39)
a

26 (23 – 29)
69 (64 – 75)
76 (70 – 81)
69 (50 – 90)
64 (38 – 94)
42 (21 – 68)
71 (50 – 94)
118 (91 – 146)
84 (61 – 104)
90
74
47
82
116
37

(66 – 112)
(60 – 88)
(35 – 57)
(71 – 93)
(94 – 138)
(27 – 49)

The estimates of Frate per 1,000 inmates_ are based on weighted valid numbers.

higher, with abusive sexual conduct more than 1.8 to 10.9 times higher than
nonconsensual sexual acts. As in Table 3, no discernible pattern exists by size of
facility.
DISCUSSION
Considerable anecdotal and empirical speculation exists about the extent to which
inmates are at risk for sexual victimization inside prisons. Methodological
limitations, ranging from biased sampling designs and survey methodology to
selective definitions of sexual victimization and perpetrators, have led to extreme
equivocation in the extant literature. The PREA legislation directed attention to the
potential problem of sexual victimization inside American prisons and provided the
means to rigorously estimate its rate of occurrence. This study, part of the PREA
initiative, measured sexual victimization inside a prison system for a single state
using state-of-the-art methodology that minimized common problems limiting
generalizability, validity, and reliability.
Several limitations are noteworthy. The first concerns sample bias. Our samples
ranged from 26 to 53% of the general population among 13 facilities. This
representation of the inmate population is significant in absolute number but may
not generalize to the full population. While we tested for non-representativeness in
terms of age, race/ethnicity, and length of incarceration and adjusted for any
deviations in the weighting strategy, the characteristics that predict variation in
sexual victimization may not be fully represented by these attributes. To the extent
that inmates who have characteristics that make them targets for sexual
victimization were systematically over- or under-represented in our samples, the

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843

TABLE 4. Six-month prevalence of sexual victimization in statewide male correctional system
grouped by population size, 2005, n = 6,964; rates per 1,000 and 95% confidence intervals
Inmate-on-inmate rate per 1,000
inmatesa (95% CI)
Abusive sexual
conduct
Facilities with populations
from 500 to 1,100
1
53 (34 – 72)
2
43 (21 – 60)
3
31 (10 – 52)
Facilities with populations
from 1,101 to 1,900
4
37 (21 – 53)
5
29 (17 – 41)
6
31 (18 – 41)
Facilities with populations
over 1,901
7
38 (22 – 52)
8
43 (32 – 55)
9
24 (17 – 33)
10
34 (27 – 42)
11
42 (26 – 60)
12
21 (13 – 28)

Staff-on-inmate rate per 1,000
inmatesa (95% CI)

Nonconsensual
sexual acts

Abusive sexual
conduct

Nonconsensual
sexual acts

21 (10 – 32)
8 (0 – 21)
26 (10 – 47)

61 (43 – 80)
52 (30 – 17)
42 (21 – 68)

13 (5 – 24)
26 (10 – 47)

18 (7 – 31)
16 (7 – 26)
25 (10 – 38)

50 (31 – 69)
109 (82 – 133)
69 (48 – 89)

26 (13 – 39)
31 (19 – 43)
22 (10 – 33)

8 (2 – 16)
32 (21 – 43)
5 (2 – 10)
14 (9 – 18)
6 (0 – 14)
7 (3 – 13)

87 (64 – 109)
65 (51 – 78)
36 (27 – 47)
70 (60 – 80)
106 (84 – 126)
28 (19 – 38)

8 (2 – 14)
22 (14 – 31)
20 (11 – 27)
22 (16 – 28)
14 (6 – 22)
13 (6 – 19)

a

The estimates of Frate per 1,000 inmates_ are based on weighted valid numbers.

rates reported herein would either, respectively, over- or underestimate sexual
victimization within these facilities. One way to account for such uncertainty is to
estimate confidence intervals. The reported confidence intervals around each of the
estimated rates in this study provide a reasonable (95%) approximation of the
range of variation in rates of sexual victimization.
The second limitation concerns biased reporting. Audio-CASI, while the most
reliable method for collecting information about activities or events that are
shaming or stigmatizing, does not correct for bias motivated by revenge against
custody officers or the prison system itself. Relations between inmates and custody
staff are complex, often fraught with tension and hostility. This survey provided
inmates with the rare opportunity to report anonymously on the conditions inside
prison, including how they are treated by custody staff. To guard against false
reporting, as part of the consent process, the importance of accurate reporting was
discussed in terms of its impact on the legitimacy of the data and survey. We
explained that misinformation was as useless as no information at all. As
mentioned earlier, many of those who chose not to participate in the survey were
antagonistic to the Bsystem^ or demoralized to the point of disinterest. Those who
participated, by and large, deliberated over questions about their interactions with
the custody staff. They frequently asked the research staff for assistance on how to
answer questions about the custody staff when most were reasonable and fair but
some were abusive and cruel. Their questions during the survey and the distributions of the responses to the questions are not suggestive of false reporting.
Also, given that the survey instruments were read and completed in real time,

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WOLFF ET AL.

involved hundreds of questions, and were completed by hundreds of inmates per
day over a 2 to 4 day period, systematic strategies for reporting against the facility
were minimized. If there was systematic false reporting of events or behaviors by
custody staff, we would have expected much higher and clustered rates, which were
not detected in the data.
Overall, rates of sexual victimization were found to vary significantly by
gender, age, perpetrator (inmate or staff), question wording, and facility. These
rates also varied if delimited to nonconsensual sexual acts or abusive sexual
conduct. On average, rates of sexual victimization were lowest for males, inmateon-inmate victimizations, and nonconsensual sexual acts. Thus, studies focusing
solely on inmate-on-inmate nonconsensual sexual acts (particularly, rape) in male
prisons will provide very conservative estimates of sexual victimization overall. In
our study, the percentage of the male inmate population experiencing such incidents
over a 6-month period was 1.5%, on average, and at any point since incarcerated,
1.6%. For male prisons, the highest rate of sexual victimization (76 per 1,000) is
associated with staff perpetrators.
These rates, based on averaging, mask considerable variation among prisons
housing men. The literature clearly demonstrates that prison environments are
heterogeneous.28,43 Our research is consistent with this literature. An individual’s
risk of sexual victimization is not equivalent across prisons even within a single
prison system. Depending on facility, a male inmate might be housed in a prison
where the risk of inmate-on-inmate sexual victimization is as high as 6.4% or as
low as 3.0%. Likewise, he might be in a facility where the risk of sexual
victimization by a staff person ranges from 3.7 to 11.8% . More research is needed
to identify the factors that predict variation in risk across male facilities. The
literature suggests that violence levels inside prisons are associated with overcrowding, management style, and availability of programming,28,44,45 but the
definition of violence in prior research focused on physical violence, not sexual.
This is an important area for future exploration.
Sexual victimization rates in the female facility were significantly higher than
those for male facilities, especially with respect to abusive sexual contact between
inmates. On average, 21.2% of female inmates reported experiencing some form of
sexual victimization by other inmates, while 7.6% reported experiencing that
behavior by staff. Nonconsensual sex acts were reported at considerably lower
rates, with 3.2% of inmates reporting a sexual assault by an inmate over a 6-month
period and 1.7% by a staff member. The percent of inmate-on-inmate rape is over
ten times higher than rape rates of adult women in the total population, and the
rate for staff perpetrated rape is almost six times higher. Compared to other studies
of sexual violence in prisons, our estimate of prevalence (3.2%) is less than half of
the 7.0% reported by Struckman-Johnson et al.15,16 and roughly two-thirds of the
4.5% sexual coercion rate reported by Hensley et al.18 In a subsequent study of
three female facilities located in Midwestern states, the Struckman-Johnson team17
estimated rates of sexual coercion of 8, 9, and 27%, with one-fifth of these events
defined as Brape^ and roughly half involving staff. The blending of types of
perpetrator (inmate vs. staff) and the types of sexual victimization (rape or
nonconsensual sex acts with abusive sexual contact) explains part of the variation
in rates among these studies, along with the different sampling designs and methods
for collecting responses. While it is customary to attribute violence to men, it may
be that the rage that motivates violence and the desire to dominant that motivates
rape are traversing the gender divide. Rates of aggravated assault, murder, and use

SEXUAL VIOLENCE INSIDE PRISONS: RATES OF VICTIMIZATION

845

of weapons among arrested female juveniles increased dramatically between 1980
and 200346 and may be foreshadowing a change in the character of the female
inmate. Both the variation and increased risk of sexual victimization that female
inmates face and the rising violence among female offenders underscores the need
for more research that includes female facilities. Sexual victimization in female
prisons has been understudied, with only four published studies,15–18 compared to
well-over a dozen studies of male prisons.12 Future research also needs to explore
the profiles of sexual victims and sexual aggressors within male and female facilities
to better understand why and in what ways sexual victimization varies within male
and female facilities.
From a public health perspective, the number of potential victims susceptible to
HIV and other health and mental health consequences as a consequence of a sexual
victimization inside prison is staggering. In 2003, there were 1,368,866 males being
housed in federal and state prisons; extrapolating from our data, this would translate
into almost 22,000 male inmates experiencing a forced sexual act, the comparable
number for the 101,179 female inmates in federal and state prisons is over 3,200. The
experience of unwanted sexual touching or forced sex and the concomitant fear of
sexual victimization have nontrivial physical, emotional, and psychological implications for current and future behavior inside and outside prison.5
The vast majority of people in prison eventually return to the community. In
general, they relocate to communities where they committed their crimes or where
they have familial or interpersonal connections. Research clearly shows that
relocation patterns after prison are not random. People leaving prison are more
likely to return to socially disadvantaged urban communities, where rates of
criminal behavior and drug use are high and opportunities for healthy and prosocial
living are low.47–49 To these communities, the victims of sexual violence arrive with
elevated needs for physical and mental health treatment, furthering the spatial
concentration of poor health.
Research on the risk of sexual victimization inside prison and its variation
across facilities provides the rationale for studying the characteristics of the
individual and the environment that elevate or lower risk levels in order to better
classify inmates for placement and to alter environments inside prison to promote
safe and humane prisons. It has been said that prisons are jungles, but this is a
truism only if we fail to act rationally and humanely.

ACKNOWLEDGEMENT
This study was supported by the Office of Justice Programs (Grant #0JP-2004-RPBX-0012) and the National Institute of Mental Health (Grant #P20 MH66170).

Appendix
SURVEY QUESTIONS REGARDING SEXUAL VIOLENCE
(MALE VERSION)
General sexual assault questions, INMATE:

 Have you been sexually assaulted by an inmate within the past 6 months here?
 Have you ever been sexually assaulted by an inmate on this bid?

846

WOLFF ET AL.

Specific sexual violence questions*, INMATE
During the past 6 months, has another inmate ever....
1. Touched you, felt you, or grabbed you in a way that you felt was sexually threatening?
2. Tried or succeeded in touching your genitals or sex organs?
3. Tried or succeeded in getting you to touch someone else’s genitals when you didn’t want to?
4. Made you have sex by using force or threatening to harm you or someone close to you?
5. Made you have oral sex by using force or threat of force?
6. Made you have anal sex by using force or threat of force?
7. Put fingers or objects in your anus against your will or by using force or threat of force?
8. Made you put fingers or objects in someone else’s anus against your will or by using force
or threats?
9. Attempted to make you have oral or anal sex against your will but penetration did not occur?
10. Required you to perform sexual acts as a way to protect yourself from future harm?

General sexual assault questions, STAFF MEMBER:

 Have you been sexually assaulted by a staff member within the past 6 months
here?
 Have you ever been sexually assaulted by a staff member on this bid?
Specific sexual violence questions*, STAFF MEMBER
During the past 6 months, has staff member ever....
1. Touched you, felt you, or grabbed you in a way that you felt was sexually threatening?
2. Tried or succeeded in touching your genitals or sex organs?
3. Tried or succeeded in getting you to touch someone else’s genitals when you didn’t want to?
4. Made you have sex by using force or threatening to harm you or someone close to you?
5. Made you have oral sex by using force or threat of force?
6. Made you have anal sex by using force or threat of force?
7. Put fingers or objects in your anus against your will or by using force or threat of force?
8. Made you put fingers or objects in someone else’s anus against your will or by using force or
threats?
9. Attempted to make you have oral or anal sex against your will but penetration did not occur?
10. Required you to perform sexual acts as a way to protect yourself from future harm?

*Questions #1, 2, and 3 were combined to create a variable indicating an
abusive sexual contact. Questions 4–10 were combined to create a variable
indicating a nonconsensual sexual act.

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