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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 fstnat@yahoo.com
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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
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Forensic responsibility of evaluators: 1)diagnose 2) risk assessment 3)opinion regarding SVP criteria
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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
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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
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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
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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
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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
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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?
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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
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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
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FBI Data on Violent Crime in the United States
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Jones & Finkelhor, 2001
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Finkelhor & Jones, 2004
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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 19981999 Canada84.6178.23 U.S.33.8732.05 ** 7 th United Nations Survey of Crime Trends
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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.”
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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
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Strength of Sexual Arousal As a Function of Age (PPG) Blanchard, R. & Barbaree, H. (2005)
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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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