Forensic Use of the Static-99R: Choice of a Comparison Group Denis L. Zavodny, Ph.D., MPA GA Dept. of Behavior Health & DD/Emory University Gregory DeClue, Ph.D., ABPP Independent Practice, Sarasota, FL
Sexual Violent Predator Considerations • Past conviction of a sexual offense • Incarceration • Mental abnormality • Deficit in volitional capacity • Likelihood of future sexual violence
Static-99/99R Norms • Revisions after discovery that more recent samples had sexual recidivism rates lower than rates observed in the developmental sample • July 2012 Workbook recommendation for selection of comparison groups (Phenix, Helmus, & Hanson).
Static-99R Comparison Groups • Local Norms • Routine “Full Population” of Convicted Sex Offenders • Non-routine/Preselected “Non-representative” Groups • Preselected Treatment Need • Preselected High Risk • Non-routine - Other
Local Norms Generally, not available.
Routine Correctional – “Full Population” • Sex Offenders released from the Arizona Department of Corrections (Bartish, Garby, Lewis, & Gray, 2003) • Canadian federal (two or more years) sex offenders in Quebec 1995-2007 (Bigras, 2007) • Contact sex offenders on probation in two boroughs of South East London (Craissati, Bierer, & South) • Sex offenders released from prison in Austria (Eher, Rettenberger, Schilling, & Pfafflin, 2009) • Sex offenders in North Dakota who were incarcerated or on probation(Epperson, 2003) • Canadian sex offenders on community supervision 2001-2005 (Hanson, Harris, Scott, & Helmus, 2007) • Sex offenders released from prison in Sweden (Långström, 2004)
Non-routine/Preselected on Risk-Relevant Characteristics or Need for Treatment – “Non-representative Groups”
Selected as Needing Treatment • New Zealand inmates convicted of child molestation who completed prison-based sex offender treatment (Allan, Grace, Rutherford, & Hudson, 2007) • Canadian inmates treated at a maximum security psychiatric facility (Brouillette-Alarie & Proulx, 2008) • UK offenders (prison treatment in the 1990s, community treatment in the early 1990s, and community treatment in the late 1990s; Harkins & Beech, 2007) • Washington state prison sex offender treatment program (Johansen, 2007) • Outpatient sex offender treatment at the University of Minnesota (Swinburne Romine, Dwyer, Mathiowetz, & Thomas, 2008) • British Columbia sex offender treatment in provincial prison (Ternowski, 2004)
Pre-selected High Risk/Needs • Referrals for pretrial forensic psychiatric evaluations in Denmark (Bengtson, 2008) • Canadian offenders flagged as potential Dangerous Offenders (subject to indeterminate sentence; Bonta & Yessine, 2005) • Canadian sex offenders with Warrant Expiry Date in 1995 (Haag, 2005) • Offenders assessed or treated at the Massachusetts Treatment Center between 1959 and 1984 (Knight & Thornton, 2007) • Sex offenders treated at the Clearwater sex offender treatment program in the federal forensic maximum-security facility in Saskatchewan (Nicholaichuk, 2001) • High-risk Canadian sex offenders detained after their Warrant Expiry Date (Wilson, Cortoni, & Vermani, 2007; Wilson, Picheca, & Prinzo, 2007)
Non-routine - Other • Canadian federal offenders who received the low or moderate intensity National Sexual Offender Treatment Program (Cortoni & Nunes, 2007) • Sexual homicide offenders (Hill, Haberman, Klusmann, Berner, & Briken, 2008) • Sex offenders treated by the North Dakota Department of Human Services (Staum, 2007).
Comparison Group Issues • Considerable score variability within groups (Abbott, 2013) • Limited detail about groups (Sreenviasan, Weinberger, Frances, & Cusworth-Walker, 2010; Thorton, 2011) • “The best method of determining which sample type is the most appropriate match to an individual is not fully known” (Phenix et al., 2012) • Criterion contamination due to overlapping characteristics between groups (Abbott, 2011) • Insertion of subjective step into actuarial assessment providing “legitimizing cover” (Prenkey, Janus, Barbaree, Schwartz, & Kaftka, 2006) or a “veneer of ‘quantification’” (Sreenviasan et al., 2010) to clinical judgment. • Choice of comparison group often the key factor in the outcome of the actuarial assessment.
Why not just select the High Risk/Needs Comparison? • High Risk/Needs group characterized as “referred for services at forensic psychiatric facilities, such as offenders referred as Mentally Disorder (sic) Sex Offenders, Sexually Violent Predators….(Phenix, et al., 2012) but no SVP candidates were included in the samples. • Intentional or unintentional bias/allegiance effect (Murrie, Boccaccini, Turner, Meeks, Woods, & Tussy, 2009; Murrie, Boccaccini, Guarera, & Rufino, 2013) • Selected High Needs/Risk group not drawn from general population of state prison. Instead, specialized treatment population between 1959 and 1984. However, there was a 49 percent decline in observed sexual abuse between 1990 and 2004 (Finkelhor & Jones, 2006).
Routine/”Full Population” • Score of 9: Estimated 5-year recidivism = 29.5 (22.8-37.2 95% CI)
Preselected for Treatment Need • Score of 8: Estimated 10-year recidivism = 39.6 (31.5-48.3 95% CI) • Score of 9: Estimated 5-year recidivism = 38.1 (32.1-44.4 95% CI)
High Risk/Need • Score of 7: Estimated 10-year recidivism = 48.6 (41.4-55.9 95% CI) • Score of 8: Estimated 5-year recidivism = 45.0 (39.3-50.8 95% CI) • Score of 8: Estimated 10-year recidivism = 55.3 (46.8-63.6) • Score of 9: Estimated 5-year recidivism = 52.4 (45.9-58.8 95% CI) • Score of 9: Estimated 10-year recidivism = 61.9 (52.2-70.7 95% CI) • Score of 10: Estimated 5-year recidivism = 59.7 (52.6-66.4 95% CI) • Score of 10: Estimated 10-year recidivism = 68.0 (67.6-77.0 95% CI)
Non-routine • Score of 8: Estimated 10-year recidivism = 46.3 (38.1-54.8 95% CI) • Score of 9: Estimated 5-year recidivism = 44.3 (36.9-52.0 95% CI) • Score of 9: Estimated 10-year recidivism = 53.1 (43.4-62.6 96% CI) • Score of 10: Estimated 5-year recidivism = 51.6 (43.6-59.6 95% CI) • Score of 10: Estimated 10-year recidivism = 59.7 (48.7-69.8 (95% CI)
Search for Recent US Samples • Sex Offender Civil Commitment Program Network • Contacting states with SVP civil commitment program • Researchers • Public records request
Screened by SVP/SDP program, referred for evaluation, and commitment recommended
Found to meet SVP criteria, probable cause found, or two evaluators opine meet commitment criteria; released without treatment
Should “Selected High Risk/Needs Comparison Group” be used because the person has been referred for SVP evaluation? • No • Although, with a recidivism rate of 25.2% over six years, Washington sample was comparable. However, Florida, Texas, and California offenders recidivated at a rate closer to the Full Population (Routine) Group.
Should comparison groups be selected based on clinical considerations? • Local norms recommended. When local norms are not available, Full Population (Routine) Group is generally the best choice • “Given that these norms are not often available, the routine sample will usually reflect the most appropriate recidivism rates as they are representative of typical sex offenders in the correctional system” (Phenix et al., 2012). • No empirical evidence showing that Preselected “Non-representative” Groups results in increased predictive accuracy. In fact, there is research that it decreases accuracy. • Should always use the Full Population (Routine) Group. Could use Preselected “Non-representative” Groups in addition to Full Population (Routine) Group is there is clear evidence of similarity between the individual’s sample and the research sample
Implications • Non-routine “non-representative” comparison groups have higher recidivism than the Full Population (“Routine”) group and provide evaluators an opportunity to arrive at higher recidivism estimates, sometimes two or three times higher than the Full Population (“Routine”) group • No empirical support for increased accuracy by the use of non-routine “non-representative” comparison groups • Extant research consistently shows that clinical adjustments from the standard actuarial rate decrease accuracy of sexual recidivism risk assessments.
Future Directions • Need research to test the accuracy of Preselected “Non-representative” comparison groups vis-à-vis the Full Population (Routine) comparison. • Need research to determine if use of structured instruments to guide comparison group selection increases accuracy of risk determination • Hanson and Phenix (2013) indicated that, based upon subsequent data analysis, they anticipate abandoning the “Selected as Needing Treatment” and “Non-routine” comparisons groups and using recommending the using only two comparison groups
DeClue, G., & Zavodny, D. L. (2013). Forensic use of the Static-99R: Part 3. Choosing a Comparison Group. Open Access Journal of Forensic Psychology, 5, 151-182. www.forensicpsychologyunbound.ws/OAJFP/Sex_Offenders_files/DeClue%20and%20Zavodny%202013.pdf
Contact Information Denis Zavodny email@example.com Gregory DeClue firstname.lastname@example.org