Q & A with Mark Olver on "Predictive accuracy of Violence Risk Scale-Sexual Offender version risk and change scores in treated Canadian Aboriginal and non-Aboriginal sexual offenders"
Olver, M. E., Sowden, J. N., Kingston, D. A., Nicholaichuk, T. P., Gordon, A., Beggs Christofferson, S. M., & Wong, S. C. P. (2016). Predictive accuracy of Violence Risk Scale-Sexual Offender version risk and change scores in treated Canadian Aboriginal and non-Aboriginal sexual offenders. Sexual Abuse: A Journal of Research and Treatment.
Abstract: The present study examined the predictive properties of Violence Risk Scale�Sexual Offender version (VRS-SO) risk and change scores among Aboriginal and non-Aboriginal sexual offenders in a combined sample of 1,063 Canadian federally incarcerated men. All men participated in sexual offender treatment programming through the Correctional Service of Canada (CSC) at sites across its five regions. The Static-99R was also examined for comparison purposes. In total, 393 of the men were identified as Aboriginal (i.e., First Nations, M�tis, Circumpolar) while 670 were non-Aboriginal and primarily White. Aboriginal men scored significantly higher on the Static-99R and VRS-SO and had higher rates of sexual and violent recidivism; however, there were no significant differences between Aboriginal and non-Aboriginal groups on treatment change with both groups demonstrating close to a half-standard deviation of change pre and post treatment. VRS-SO risk and change scores significantly predicted sexual and violent recidivism over fixed 5- and 10-year follow-ups for both racial/ancestral groups. Cox regression survival analyses also demonstrated positive treatment changes to be significantly associated with reductions in sexual and violent recidivism among Aboriginal and non-Aboriginal men after controlling baseline risk. A series of follow-up Cox regression analyses demonstrated that risk and change score information accounted for much of the observed differences between Aboriginal and non-Aboriginal men in rates of sexual recidivism; however, marked group differences persisted in rates of general violent recidivism even after controlling for these covariates. The results support the predictive properties of VRS-SO risk and change scores with treated Canadian Aboriginal sexual offenders.
The full article is available via open access from:
Could you talk us through where the idea for the research came from?
The idea for the research came from a recent Canadian legal decision, Ewert v. Canada, that came out in September 2015. The plaintiff, a man of M�tis descent, who had been in custody for more than 30 years on murder and attempted murder (both sexually motivated offenses) had sued the federal government with the contention that actuarial risk assessment tools, and other certain forensic measures, were biased against individuals of Aboriginal ancestry and that he had been caused harm through their use in his case. The tools identified were the Violence Risk Scale-Sexual Offender version (VRS-SO), Static-99, Violence Risk Appraisal Guide, Sex Offender Risk Appraisal Guide, and the Psychopathy Checklist-Revised. In his decision, Justice Phelan ruled that the evidence accumulated thus far had not been sufficient to justify their applications to offenders of Aboriginal descent and strongly cautioned the Correctional Service of Canada (CSC) against using these and related tools with this population until further research supporting their psychometric properties with Aboriginal persons had been conducted. Given the overrepresentation of Aboriginal persons in Canadian corrections, for some time we wished to do such research examining the psychometric properties of the VRS-SO with this population but we didn�t have the sample size to do so. Justice Phelan�s decision was an important call for research and by the time the decision was released we had accumulated sufficient numbers across three CSC-based studies of treated sex offenders to do the work. The decision thus provided an extremely powerful impetus for our group to examine the predictive properties of VRS-SO risk and change scores with Aboriginal offenders.
What kinds of challenges did you face throughout the process?
The decision had issued a challenge to the federal government specifically and to researchers outside the service more generally who may have capacity to explore these questions; but a follow-up decision had yet to be made about whether there may be a formal prohibition issued concerning the use of these tools with Aboriginal offenders in federal corrections. One key issue was time, as my co-authors and I were hoping that the results may assist future decisions on this matter, but it was uncertain when that would be or what the results would be. So I made a mad dash to obtain IRB approval to link the data sets and to conduct these Aboriginal analyses, to do the actual work involved, and then ultimately to get the word out as quickly as possible when we had a good understanding about the findings. As it turns out, a remedy hearing was held the last week of April 2016 to speak to the issues and concerns raised by the judge and to examine future research directions on these tools with Aboriginal offenders. I had the privilege of appearing as an expert witness to give testimony on post-trial research and use of these tools with Aboriginal offenders. The manuscript had been accepted for publication in SAJRT just the week prior to me appearing in court.
What kinds of things did you learn about co-authorship as a result of producing this article?
I have a great team of colleagues who have contributed data, resources, and ideas to support the validation of the VRS-SO. The authorship list, which features a diverse group of VRS-SO contributors is as much a statement of support for the findings generated and the use of the tool to assess risk, identify treatment needs, and track change with adult male Aboriginal sex offenders.
What do you believe to be to be the main things that you have learnt about Aboriginal sex offenders and/or Risk Assessment?
The results are consistent with past research showing that structured risk assessment tools can predict recidivism outcomes with Aboriginal offenders; in essence the tools do work with Aboriginal offenders. That the predictive accuracy magnitudes were consistently slightly lower for Aboriginal offenders is also consistent with available research. The higher recidivism base rates we see with Aboriginal offenders, however, do not align neatly with the higher risk scores they also receive; base rates can be impacted by other unmeasured variables and identifying these variables is an extremely important area of ongoing research. Perhaps the most encouraging finding for us was to see that the men across ancestral groups made broadly the same amounts of change from sex offender treatment, and these changes showed similar magnitudes in predicting decreased sexual and violent recidivism. The results highlighted to us that a structured dynamic tool, such as the VRS-SO, that can track and measure change can actually be used to help these men in their commitments and efforts to lower their sexual reoffending risk in preparation for reintegration back into the community.
Now that you�ve published the article, what are some implications for practitioners?
The results support the appropriate use of the VRS-SO and the Static-99R with men of Aboriginal ancestry to assess risk, inform treatment programming, and to evaluate changes in risk. Any assessment also needs to take into consideration unique cultural, situational, personal, and historical background factors to contextualize conclusions and risk management recommendations.
Mark Olver, PhD
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