Title: Risk Assessment of Sexual Offenders
1Risk Assessment of Sexual Offenders
- Mr Steven M Wright
- University of South Australia
- ? 2001
2Why the current emphasis ?
- Media reporting
- Political pressures
- community notification Megans Law (USA)
Sarahs Law (UK) - Guide Intervention who and what to target
- Legal obligations / Ethical concerns
- Sexual predator legislation (United States)
- Duty to warn/protect
3Risk Assessment Objectives(Hart, 2001)
- We never know an individuals risk for violence
we merely estimate it assuming various
conditions. - Evaluations of individuals to
- (a) Characterise the risk that they will commit
violence in the future, and - (b) Develop interventions to manage or reduce
that risk - The task is to understand the factors associated
with how and why individuals chose to offend in
the past, and to determine whether these or other
factors might lead the individual to make similar
choices in the future.
4Recidivism risk factors (Hanson, 2000)
- Static historical and unchangeable
- age, criminal history, demographic
characteristics - Dynamic predictors
- Stable dynamic (sexual preferences, cognitive
distortions) - Acute dynamic (intoxication, emotional states)
5Sexual offense recidivism
- Although there is a rich clinical literature on
sexual offenders, there has been relatively
little work on assessing sexual violence risk
among sexual offenders, particulary with regard
to sexual-reoffending. - Hanson Bussiere (1998) meta-analysis of the
scientific literature (28,972 offenders)
highlighted the importance of historical or
static factors in sexual violence recidivism
risk. - sexual deviance (phallometric assessment) Age
(young) - prior sexual offences Never married
- early onset of sexual offending Personality
disorders - victim choices (family membersltacquaintancesltstran
gers) - failed to attend/dropped out of treatment
- Concluded that recidivism rate for sexual
violence low contrary to popular opinion. 13.4
percent of offenders committed a new sexual
offense within the 4-5 year follow up period. -
6Among sexual offenders, non sexual recidivism was
best predicted by the same variables that predict
recidivism among nonsexual criminals (Andrews
Bonta, 1994). Often these offenders tended to be
young, single and have antisocial/psychopathic
personality disorders, and have a history of
prior violent and nonviolent offenses. Factors
not related to sexual offense recidivism included
having a history of sexual abuse as a child,
substance abuse and general psychological
problems (anxiety, depression, low self-esteem
etc.)It is suggested that whilst the extent to
which sexual offenders are distressed does not
predict recidivism, such offenders may react
deviantly when distressed.
7Hanson Harris (2000)Dynamic risk factors in
sexual offendingThe purpose of this study was
to identify factors that could be useful for
officers supervising sexual offenders in the
community. Overall, substantial differences were
observed between the 208 sexual offenders who
sexually recidivated while on community
supervision and a comparison group of 201
non-recidivists. In comparison to the
non-recidivists, the recidivists had a greater
history of sexual deviance, such as diverse types
of victims, stranger victims, juvenile offenses
and paraphilias (e.g., exhibitionism,
cross-dressing). As well, the recidivists showed
more signs of an antisocial lifestyle than did
the non-recidivists. The recidivists were more
likely to meet criteria for antisocial
personality, psychopathy (PCL-R), and had higher
scores on objective risk scales (SIR and VRAG).
8Officer interviews indicated that the recidivists
displayed more problems while on supervision than
did the non-recidivists. In particular, the
recidivists were generally considered to have
poor social supports, attitudes tolerant of
sexual assault, antisocial behaviour, poor
self-management strategies and difficulties
cooperating with supervision as indicated by
being disengaged, manipulative or absent. The
overall mood of the recidivists and
non-recidivists was similar, and each had
equivalent levels of life stress and negative
affect, but the recidivists tended to show an
increase in anger and subjective distress just
prior to re-offending. In other words,
psychological symptoms appeared as acute, but not
stable, risk factors. With rare exceptions, the
same risk factors applied to both rapists and
child molesters.
9Statistical Methods of describing and quantifying
the accuracy of risk predictions
- Correlations
- ROC AUCs (receiver operating characteristic
analysis)
10Sex Offender Risk Assessment Measures (Campbell,
2000)
- Professional judgement
- Unstructured or clinical
- Structured
- Actuarial decision making
- Clinically Adjusted Actuarial Prediction
-
- Multifactorial approaches and classification
trees (to come)
11Professional judgementMost commonly used
method for violence risk assessmentFlexible,
requires limited training and resources
- Un-structured based on idiosyncratic
impressions - Poor predictive validity,
unreliable and false positive bias - Predictive accuracy only slightly better than
chance - (r.10, Hanson Bussiere, 1998)
- Structured Imposes structure on evaluation
- Must refer to at minimum a fixed and explicit
set of risk factors. Combine ratings on such
to guide - assessment of risk.
- Sexual Violence Risk 20
- (SVR-20 Boer, Hart, Kropp
Webster, 1997) - Structured Risk Assessment 99 (SRA-99
Thornton, 1999) - Matrix 2000 (Thornton, 2000)
12SVR-20 (Boer, Hart, Kropp Webster, 1997)
- 20 standard risk factors
- Three main areas Psychosocial adjustment
- Sexual offending
- Future plans
- Rate as present, possibly present or not
present - Translate into low, moderate, or high risk
categories
13Sample Conclusion
- Based on a comprehensive risk assessment, it is
my opinion that should he be released into the
community Mr Smith poses a high risk for sexual
violence relative to other sex offenders
incarcerated in the Correctional Service. - According to the available information, all of Mr
Smiths sexual offences have been paedophilic in
nature, involving the non-coercive sexual contact
of young boys with whom he was acquainted through
casual contact. There is no information to lead
me to believe that his offences will change in
nature or escalate in severity in the near
future. - Based on his past offences, if Mr Smith
recidivates his victims are most likely to be
boys between the ages of 6-12 years who live
within a few miles of his residence. Given the
long standing nature of Mr Smiths paraphilia,
its resistance to treatment, and his extensive
history of sexual offending, the most effective
way to manage his risk of sexual violence is
through incapacitation, that is, by denying his
request for parole. Should Mr Smith by released
into the community, risk management strategies
should focus on intensive supervision. Electronic
monitoring, frequent meetings with a parole
officer might be effective supervision strategies.
14Correlations/ ROC AUCs Hart (2000)
- Any violence
Sexual violence - r AUC r AUC
- PCL-R .45 .76 .20 .69
- VRAG .56 .83 .26
.71 - SORAG .64 .88 .36 .77
- RRASOR .40 .73 .48 .77
- SVR-20 .52 .81 .31 .74
15The SVR-20 (1998) can be purchased from
Psychological Assessment Resources
16Actuarial devices
- Commonly-used adjunctive method for violence risk
assessment - Utilise statistical techniques to generate risk
predictors - Generally equal or superior to clinical judgement
with respect to consistency (reliability) and
accuracy (validity) - Highly structured/systematic
- Objective limited role of discretion,
empirically based and scientific -
- Rapid Risk Assessment for Sexual Offense
Recidivism - (RRASOR Hanson, 1997)
- Sexual Offence Risk Appraisal Guide
- (SORAG Quinsey, Harris, Rice Cormier, 1998)
- Minnesota Sex Offender Screening Tool (Revised)
- (MnSOST-R Epperson, Kaul Huot, 1995)
- Static 99 (Hanson Thornton, 1999)
17Rapid Risk Assessment of Sexual Recidivism
(RRASOR Hanson, 1997)
- 4 item actuarial instrument rated from official
records - Intended to be relatively brief screening
instrument for predicting sexual offense
recidivism - Based on meta-analytic research and re-analysis
of existing data sets. - Items weighted according to ability to predict
likelihood of recidivism over periods of 5-10
years. Total scores range from 0 6 with a 10
year estimated likelihood of recidivism ranging
from 6.5 73.1 percent. Most offenders have
scores which range between 1 and 4. - Items Prior sex offenses (not
including index offenses) - Age at release (current age)
- Victim gender
- Relationship to victim
18RRASOR Summary
- No manual
- Minimal peer reviewed studies
- Doesnt consider deviant sexual preferences,
personality, treatment compliance or other
dynamic variables. - Insensitive to context, change
- Utility in assessing post-treatment changes in
risk status limited. - Potentially useful psychological instrument for
establishing elevated risk of sexual violence - Good predictive accuracy in development and
validation samples (Hanson Thornton, 2000) - r 0.27 AUC 0.71 (Hanson, 1997) sexual
recidivism - r 0.22 AUC 0.72 (Sjostedt Langstron,
2000) - sexual recidivism
4 year follow up
19The RRASOR (1997) is available to download from
- http//www.sgc.gc.ca/epub/corr/e199704/e199704.htm
20Sex Offender Risk Appraisal Guide (SORAG
Quinsey et al, 1998)
- Authors strongly pro-actuarial based on
Penetanguishene studies - Modification of the VRAG (Quinsey et al, 1998)
- Do the findings generalise ?
- the universe is homogenous with respect to
forensic institutions (Quinsey et al, 1998) - 14 item actuarial instrument, with range of
scores from 1 9. - Includes both static and dynamic factors
- At least four of the factors included in the
items have received little empirical support (ie
history of alcohol abuse history of non-violent
offenses marital status diagnosis of
schizophrenia) (Campbell, 2000)
21SORAG (1998) Items
- Living with biological parents until age 16
- Elementary school maladjustment
- History of alcohol problems
- Marital status
- Nonviolent offense history
- Violent offense history
- Sexual offense history
- Sex and age of index victim
- Failure on prior conditional release
- Age at index offense
- DSM-III criteria for any personality disorder
- DSM-III criteria for schizophrenia
- Phallometrically measured deviant sexual
interests - PCL-R score
22SORAG (1998) Summary Likelihood of recidivism
is estimated for only general violence Restricted
in clinical usage due to inclusion of PCL-R
(training requirements) No manual. Lack of peer
reviewed support. ROC-AUCs 0.82 (Belanger
Earls, 1996) parole failure or recidivism of any
kind. 0.63 (Firestone, Bradford, Greenberg, Nunes
Broom, 2001) violent (including
sexual) recidivism follow up 7 years
23The SORAG (1998) is available inQuinsey, V.L.,
Harris, G.T., Rice, M.E. Cormier, C.A. (1998).
Violent Offenders Appraising and Managing Risk.
The American Psychological Associationhttp/
/www.apa.org/books/431604A.html
24Minnesota Sex Offender Screening Tool -
Revised(MnSOST-R Epperson, Kaul Hesselton,
(1998)
- 16 item actuarial instrument, constructed
applying retrospective methods - Incorporates both historical and institutional
information (ie treatment participation). - Designed specifically to predict sexual
recidivism (unlike the VRAG and SORAG) - Scores divided into 4 categories, with estimated
recidivism rates from 16 88 percent over 6
years.
25- Correlations/ ROC AUCs
- More accurate at discriminating between sexual
recidivists and non-recidivists than the RRASOR. - r 0.45 0.77 AUC (Epperson et al, 1998)
- sexual recidivism follow up 6 years
- r 0.35 0.73 AUC (Epperson et al, 2000)
- sexual recidivism follow up 6 years
26The MnSOST-R (1998) can be downloaded from
- http//psych-server.iastate.edu/faculty/epperson/m
nsost_download.htm
27Static-99(Hanson Thornton, 1999)
- Actuarial instrument consisting of 10 items
- Combination of items from 2 scales (RRASOR
Hanson, 1997) and Thorntons Structured Anchored
Clinical Judgement Scale (SAJC Grubin, 1998) - Sample N 1,301 (Canada UK)
- Moderate predictive accuracy for sexual
recidivism (r.33, AUC .71) and violent
(including sexual) recidivism (r.32, AUC .69). - Only small incremental improvements over the
original two scales. - Reliance on static factors.
28Static-99 (Hanson Thornton, 1999) Items
- Prior sexual offences (same rules as in RRASOR)
- Prior sentencing dates (number of distinct
occasions on which the offender has been
sentenced for criminal offences of any kind) - Any conviction for non-contact offences
- Index non-sexual violence
- Prior non-sexual violence
- Any unrelated victims
- Any stranger victims
- Any male victims
- Young
- Single
29The STATIC-99 can be downloaded from
- http//www.sgc.gc.ca/epub/corr/e199902/e199902.htm
30Clinically Adjusted Actuarial Prediction
- Adjusting actuarial predictions either up or down
depending on professional judgement - Structured Risk Assessment 99 (SRA-99
Thornton, 1999) - Stepwise process including
- Initial classification of risk Static-99
- Consider offenders functioning on dynamic risk
factors to revise the original risk
classification - Consider offenders response to treatment
- Consider offenders typical offence pattern in
association with situational factors - Reflects diversity of assessment domains.
- Yet to be subject to systematic empirical
evaluation. -
31Latest researchPredictive accuracy
(Correlations/ROC - AUCs)Barbaree, Seto,
Langton Peacock (2001)
VRAG, SORAG, RRASOR Static-99 predicted general
recidivism, serious (violent and sexual)
recidivism, and sexual recidivism. MnSOST-R
predicted general recidivism but not serious or
sexual recidivism, PCL-R predicted general and
serious recidivism but not sexual recidivism.
32Conclusions
- It is possible to predict sexually violent
recidivism in sex offenders with moderate
accuracy - Validity of structured professional judgements
may equal that of actuarial instruments
33References
- Hanson, R.K. Harris, A.J.R. (2001). A
structured approach to evaluating change among
sexual offenders. Sexual Abuse Journal of
Research and Treatment, 13(2) 105-122. - Â
- McCarthy, J. (2001). Risk assessment of sexual
offenders. Psychiatry, Psychology Law, 8(1)
56-64. - Â
- Hanson, R.K. Thornton, D. (2000). Improving
risk assessments for se offenders A comparison
of three actuarial scales. Law and Human
Behavior, 24(1) 119-136. - Â
34Hanson, R.K. Harris, A.J.R. (2000). Where
should we intervene ? Dynamic predictors of
sexual assault recidivism. Criminal Justice
Behavior, 27(1) 6-35. Hanson, R.K. Bussiere,
M.T. (1998). Predicting relapse a meta-analysis
of sexual offender recidivism studies. Journal of
Consulting and Clinical Psychology, 66(2)
348. Barbaree, H.E., Seto, M.C., Langton, C.M.
Peacock, E.J. (2001). Evaluating the predictive
accuracy of six risk assessment instruments for
adult sex offenders. Criminal Justice Behavior,
28(4) 490-521.
35The Sex Offender Need Assessment Rating (SONAR)
A Method for Measuring Change in Risk
Levels2000-1By R. Karl Hanson Andrew
HarrisCorrections ResearchDepartment of the
Solicitor General of Canadahttp//www.sgc.gc.ca/e
pub/corr/e200001a/e200001b/e200001b.htmThe
Development of a Brief Actuarial Risk Scale for
Sexual Offense Recidivism1997-04By R. Karl
Hanson, Ph.D.Department of the Solicitor General
of Canadahttp//www.sgc.gc.ca/epub/corr/e199704/e
199704.htm Â
36Static 99 Improving Actuarial Risk Assessments
for Sex Offenders1999-02By R. Karl
HansonDepartment of the Solicitor General of
Canada, OttawaDavid ThorntonHer Majestys
Prison Service, Londonhttp//www.sgc.gc.ca/epub/c
orr/e199902/e199902.htm Dynamic Predictors Of
Sexual Recidivism1998-1by R. Karl Hanson
Andrew HarrisCorrections ResearchDepartment of
the Solicitor General Canadahttp//www.sgc.gc.ca/
epub/corr/e199801b/e199801b.htm
37Predictors of sexual offender recidivism a
meta-analysis1996-04By R. Karl Hanson Monique
T. BussièreCorrections ResearchDepartment of
the Solicitor General Canadahttp//www.sgc.gc.ca/
epub/corr/e199604/e199604.htm