Risk Assessment in the SVP Context

Natalie Novick Brown, PhD, SOTP

12535 15th St. NE, Suite 201

Seattle, Washington 98121

425-275-1238

fstnat@yahoo.com

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

Forensic responsibility of evaluators:

1) diagnose

2) risk assessment

3) opinion regarding SVP criteria

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

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

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

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

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

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?

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

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

FBI Data on Violent Crime in the United States

Jones & Finkelhor, 2001

Finkelhor & Jones, 2004

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 residents1998 1999

Canada 84.61 78.23

U.S. 33.87 32.05

** 7th United Nations Survey of Crime Trends

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.”

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

Strength of Sexual Arousal As a Function of Age (PPG)

Blanchard, R. & Barbaree, H. (2005)

13 16 19 22 25 28 31 34 37 40 43 46 49 52 55 58 61 64 67 70 73 76 79

Age at Testing

0

3

6

9

12

15

18

21

24

27

Mean of Three Largest Responses (cc)

All Patients

Observed

Predicted

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)

-5

0

5

10

15

20

0 20 40 60 80

Hanson (2002) (.96)(N=4,673)Thornton (2006) (.86)(N=752)Barbaree et al (2003)(.99) (N=468)Hanson (in press) (.98)(N=3,452)Fazel et al (2006) (.99)(N=1,303)

Recidivism

Age-at-release from custody