Transcript Risk Factors

Risk Assessment in the
SVP Context
Natalie Novick Brown, PhD, SOTP
12535 15th St. NE, Suite 201
Seattle, Washington 98121
425-275-1238
[email protected]
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:
1994:
1996:
1996:
First civil commitment law in WA State
(now in 18 states)
Wetterling Act requires sex
offender registration
Megan’s Law requires community
notification
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 residents
1998
1999
Canada
84.61
78.23
U.S.
33.87
32.05
** 7th United Nations Survey of Crime Trends
PROBLEM #3: Actuarials overpredict 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
declines thereafter
steadily
Behavioral:
--- reduction in sexual arousal / interest / fantasy
--- lower frequency in erections / orgasm /
intercourse / masturbation
Strength of Sexual Arousal As a Function of
Age (PPG)
27
Blanchard, R. & Barbaree, H. (2005)
Mean of Three Largest Responses (cc)
24
All Patients
21
18
15
12
9
6
3
0
79
76
73
70
67
64
61
58
55
52
49
46
43
40
37
34
31
28
25
22
19
16
13
Age at Testing
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)
Recidivism
20
15
10
5
0
0
-5
20
40
60
80
Age-at-release from custody
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)