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Risk Assessment in the SVP Context Natalie Novick Brown, PhD, SOTP 12535 15 th St. NE, Suite 201 Seattle, Washington 98121 425-275-1238

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Presentation on theme: "Risk Assessment in the SVP Context Natalie Novick Brown, PhD, SOTP 12535 15 th St. NE, Suite 201 Seattle, Washington 98121 425-275-1238"— Presentation transcript:

1 Risk Assessment in the SVP Context Natalie Novick Brown, PhD, SOTP th St. NE, Suite 201 Seattle, Washington

2 Ethical responsibility of evaluators:  To be objective (i.e., not influenced by “yuck” factor)  To form opinions that are consistent with the science  To communicate those opinions clearly and understandably  To inform the jury about weaknesses in opinion or the science

3 Forensic responsibility of evaluators: 1)diagnose 2) risk assessment 3)opinion regarding SVP criteria

4 Diagnosis  Must be based on specific DSM-IV-TR diagnostic criteria and include more than just the offense behavior itself (which every sex offender has)  Symptoms must be current or at least recent

5 Beyond the diagnosis:  There must be evidence of recent/current problems in sexual self-control beyond the date of the last sex offense (= ongoing symptoms) that predisposes the respondent to engage in sexual violence  There also must be evidence that the diagnosis causes the impairment in sexual self-control

6 Risk assessment = determining if the offender currently has current traits that are scientifically linked to re-offending 1)Static risk traits = unchanging factors evident at the time of the index offense 2) Dynamic risk traits = factors that change with time 3)Maturational traits = factors that change with age … predictably and without fail … cannot be reversed

7 Risk assessment: 2 methods 1)Actuarials (e.g., Static-99): combine a few risk factors that correlate with increased risk of recidivism – ignores dynamic and maturational factors 2)Base rates: prevalence of sexual recidivism within a specific population for a given period of time

8 Which to use?  Actuarials are only appropriate when the base rate is relatively high (i.e., 25-30% or more at a minimum), and the Respondent matches the actuarial development sample in key traits  Otherwise, base rates are the most accurate guideline for predicting re-offense because they take into account maturational factors

9 For an actuarial to be accurate, Respondent must “match” actuarial sample in key traits:  In terms of offense characteristics –Rape vs. child molestation –Geographic location / jurisdictional sanctions –Time period  In terms of offender characteristics –Age –Ethnicity?

10 Static-99 (and RRASOR) problems:  Normed on British and Canadian populations with very high risk offenders (i.e., high base rates), unlike U.S. prison populations  Sampling times are out-dated and do not reflect U.S. reality  Average offender age = 34.5  Not designed for SVP context

11 PROBLEM #2: Actuarials over-predict recidivism because they were developed prior to recent restrictions in U.S. law 1990:First civil commitment law in WA State (now in 18 states) 1994:Wetterling Act requires sex offender registration 1996:Megan’s Law requires community notification 1996:Amber Alert involves emergency broadcasts re missing children

12 FBI Data on Violent Crime in the United States

13 Jones & Finkelhor, 2001

14 Finkelhor & Jones, 2004

15 Comparison of Rape Offense Rates in Canada / U.S. 1998/99: Canada’s rates are 2.7 times higher than U.S. rates Rate per 100,000 residents Canada U.S ** 7 th United Nations Survey of Crime Trends

16 PROBLEM #3: Actuarials over- predict if age exceeds 40 Hanson (2005) re Static-99:  “…offenders over age 41 started to show lower age related recidivism risk than 18 year olds,” and the “rates declined gradually thereafter with further increases in age.”  “Average recidivism rates steadily declined from 14.8% in offenders less than 40 to 8.8% for offenders in their 40s, 7.5% for offenders in their 50s, and 2.0% for offenders greater than 60.”  “When controlling for Static-99 scores, the influence of age was curvilinear between the ages of 18 and 40, with 30 years being the age at greatest risk.”


18 Age-related Reduction in Male Sex Drive  Biological: ---testosterone peaks in late teens and steadily declines thereafter  Behavioral: ---reduction in sexual arousal / interest / fantasy ---lower frequency in erections / orgasm / intercourse / masturbation

19 Strength of Sexual Arousal As a Function of Age (PPG) Blanchard, R. & Barbaree, H. (2005)

20 Barbaree (2006): Recidivism as a function of age-at- release from custody corrected to 5 years time-at-risk (from Hanson, 2002; 2006; Thornton, 2006; Barbaree et al., 2003; Fazel et al., 2006) (Total N=8,879) Recidivism Age-at-release from custody

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