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					  How should we advance our
 knowledge of risk assessment
 for internet sexual offenders?
      R. Karl Hanson & Kelly M. Babchishin
                   Public Safety Canada

R. Karl Hanson, Ph.D.
Senior Research Scientist
Public Safety Canada
Karl.hanson@ps-sp.gc.ca

Global symposium for examining the relationship between online and
offline offenses and preventing the sexual exploitation of children, Chapel
Hill, North Carolina, April 5-7, 2009
           Risk Assessment
• Base rate
  – The probability that the “typical” member of
    the class will fail
• Risk factors
• Risk evaluations
  – Combination of risk factors
        What is a risk factor?
• Variation in the factor is associated with
  variation in the outcome
• Needs to be established empirically
                               Sexual
   Initial                     Recidivism
   Assessment      Follow-up


                                Yes

Any male victims                No

                                Yes
Only female
victims                         No
 Sexual Recidivism Rates (%)
                              5 years 10 years 15 years


Rapists                       14      21       24


Incest offenders               6       9       13


Girl victim child molesters    9      13       16


Boy victim child molesters 23         28       35
                Recidivates?

                no         yes


          yes   32             8   40
Single?                            (20%)

          no
                53             7   60
                                   (11.7%)


                85         15      100
       Measures of Association
•   Correlation coefficients – r, phi
•   Rate ratio, odds ratio
•   Standardized mean differences – d
•   Percent correct (hits, false alarms)
•   ROC curves
Sexual recidivism by marital status (single)

Study                    Correlation Sample Size
Fitch                        .31             139
Hanson                       .22             191
Quinsey                      .18             178
Proulx                       .12             373
Frisbie & Dondis             .10            1153
Thornton                     .07             204
Reddon                       .04             296
Bonta & Hanson               .01             316
   Mean = .11 (.07 to .15),     Q = 9.62, p >.25
Summary of Meta-Analyses of Risk
  Factors for Sexual Offenders


• Hanson & Bussiere, 1996, 1998
• Hanson & Morton-Bourgon, 2004, 2005,
  2009
• Mann, Hanson, & Thornton, in preparation
           Main Risk Factors
•   Young Age
•   Sexual Deviancy
•   Antisocial Orientation
•   Problems with Secure Adult Attachment
•   Negative Social Influences
                Risk Factors

                         d           N (k)

Young age                .26    6,969 (21)

Prior sex offences       .39   11,294 (29)

Male victims             .22   10,294 (19)

Non-contact sex offences .31   10,238 (22)

Diverse sex crimes       .20     6,011 (5)
                 Risk Factors

                         d           N (k)

Sexual pre-occupation   .39      1,119 (6)

Deviant sex interests   .31     2,769 (16)

 Children (PPG)         .32     1,278 (10)

 Violence               .18      1,523 (8)

 Other paraphilia       .21        477 (4)
                 Risk Factors

                         d            N (k)

Any prior offences       .32    14,800 (31)

Antisocial Orientation   .23    23,012 (65)

Never Married            .32      2,850 (8)

Emotional congruence     .42        419 (3)
with children
Negative social          .26      1,736 (7)
influences
     Risk Scales for Sexual Offenders

                    d                   N (k)

Static-99           .67        20,010 (63)

RRASOR              .60        11,031 (34)

Static-2002         .70         3,330 (8)

MnSOST-R            .76         4,672 (12)

Risk Matrix –2000   .67         2,755 (10)
   How Similar are Online and
    Offline Child Molesters?

• Overlap: Same people
• Overlap: Same characteristics
• Recidivism rates
  – Risk factors
  – Base rates
Studies examining prior contact sex offences among online offenders
Study                             N      % with contact offences       Source
Bourke & Hernandez (2009)        155     84.5% (n = 131)           Self-reports
Buschman & Bogaerts (in press)   38      55.3% (n = 21)            Self-reports (polygraph)
Coward et al. (2009)             128     32.8% (n = 42)            Prior arrests/charges
Elliot et al. (2008)             494     10.9% (n = 54)            Prior convictions
Galbreath et al. (2002)          39      7.7% (n = 3)              Prior charges
Jung & Gulamhusein (2007)        29      13.8% (n = 4)             Prior charges
Laulik et al. (2007)             30      6.7% (n = 2)              Prior convictions
Neutze et al. (2009)             108     57.4% (n = 62)            Self-reports
Quayle & Taylor (2003)           23      47.8% (n=11)              Self-reports
Seto et al. (2006)               100     43% (n = 43)              Prior charges
Seto & Eke (2005)                201     11.9% (n = 24)            Prior charges

Seto & Eke (2008)                301     5% (n = 15)               Prior charges/convictions
Sullivan (2007)                  215     13% (n = 28)              Convictions
Webb et al. (2007)               90      14.4% (n = 13)            Convicted and unconvicted
                                                                   charges/allegations
Wollak et al. (2005)             1,713   11% (n = 188)             Prior arrests
Proportion with prior contact sex   1.00

                                    0.90                                   Official sources
                                                                           Self-report sour
                                    0.80

                                    0.70
                                    0.60
            offence




                                    0.50

                                    0.40
                                    0.30

                                    0.20
                                    0.10

                                    0.00
                                           0   500    1000      1500    2000         2500

                                                     Inverse variance

  Note. Two outliers (in terms of inverse variance) were removed. Elliot et al. (2008)
  and Wollak et al. (2005)
Proportion of online offenders with a history of contact
sex offences
                       Overall
                      proportion
                      (95% CI)      Q           N        k
Overall             .16 (.15-.17)   785.27*     3,664 15
  Outlier reduced   .14 (.12-.15)   211.10*     3,509 14
  (Bourke &
  Hernandez, 2009)
Official records        .12 (.11-.13)   62.16**    3,212   10
 Outlier reduced        .12 (.11-.13)   23.14*     3,112    9
  (Seto et al., 2006)
Self-report             .64 (.60-.68)   111.82**    452     5
 Outlier reduced        .45 (.40-.51)    17.11*     297     4
  (Bourke &
  Hernandez, 2009)
Proportion of online offenders with a history of contact
sex offences (random versus fixed effects)
                                 Overall proportion
                            (95% Confidence Intervals)
                              Random            Fixed
Overall                       .29 (.19-.38)   .16 (.15-.17)
  Outlier reduced (Bourke &   .23 (.28-.19)   .14 (.12-.15)
  Hernandez, 2009)
Official records              .15 (.11-.19)   .12 (.11-.13)
 Outlier reduced (Seto et     .13 (.10-.16)   .12 (.11-.13)
  al., 2006)
Self-report                   .56 (.33-.79)   .64 (.60-.68)

  Outlier reduced (Bourke &   .48 (.33-.62)   .45 (.40-.51)
  Hernandez, 2009)
1.0


0.8


0.6


0.4


0.2


0.0
               *         d             *                  *        d             *
   d om    d om       ixe        ix ed        d om    d om      ixe        ix ed
 an                 F        F              an                F        F
R       Ran                                R       Ran

             Official                             Self-report
 *outlier removed
      Overlap: Same People
• 1 out of 8 (13%) caught for both
• 1 out of 2 (50%) admit to both
      How do risk factors cause
            recidivism?
• Linear Theory
• Dimensional Theory
• Psychological Theory
  – E.g., Theory of Planned Behaviour (Ajzen)
                 Traffic Accidents




Number of Jobs
                               Sexual Recidivism


     Non-contact
     sex offences
Traffic Accidents
                    Lifestyle Impulsivity


Number of Jobs



                        Sexual Recidivism




 Non-contact          Deviant Sexual
sexual offences          Interests
+ Pedophilia
+ Emotionally close to kids
- Views adult-child sex as wrong       Attitude
- Stake in conformity

+ Bad friends                           Norms       Intention
- Prosocial influences
                                     Perceived
+ Knowledge of offending             control
+ Self-efficacy

                                   Actual Control
+ Access to victims
- Surveillance
                                                    Offence
+ Pedophilia
+ Emotionally close to kids
- Views adult-child sex as wrong       Attitude
- Stake in conformity

+ Deviant internet peers                Norms       Intention
- Prosocial influences
                                     Perceived
+ Knowledge of internet              control
+ Self-efficacy

                                   Actual Control
+ Access to victims
- Surveillance
                                                    Offence

				
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posted:7/5/2011
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