The Cogency of Risk Assessments

Abstract

Preventive detention schemes rely on assessments of risk carried out by forensic practitioners. Corrective services departments and other organs of the state inevitably present the approaches they adopt and the tools they employ in this endeavour as being “best practice” and “evidence based”. Typically these assessments are conducted according to a bureaucratic template and are based on a selected suite of tests that are heavily biased towards actuarial assessment. The validity of this approach is gravely suspect as is the failure of many forensic professionals to properly identify the diagnostic accuracy/inaccuracy of the tests and methods they rely upon in conducting risk assessments. This article iterates the methodological and evidentiary problems with risk assessment of sexual offenders. It is concluded that common extant approaches lack scientific objectivity and fail to provide the courts with cogent evidence. As a result of these errors in investigatory processes miscarriages of justice are inevitable.

Key words:

• actuarial measures
• expert evidence
• preventative detention
• public policy
• risk assessment
• sex offenders
• structured professional judgement
• supervision orders

Notes

1. Professor Ian R. Coyle: Professorial Associate, Bond University, Centre for Law Governance and Public Policy; Principal Consultant, Safetysearch Forensic Consultants, PO Box 8386 Gold Coast Mail Centre, Bundall, Qld., 9726; email ([email protected]). The author would like to thank Professors Patrick Keyzer, Don Thomson, Bernadette McSherry and Paul Wilson for their helpful comments on the manuscript and their encouragement.

2. Ninety-eight Session of the Human Rights Committee 8 to 26 March 2010, Communication No. 1629/2007, adopted 18 March 2010.

3. The Dangerous Prisoners Sexual Offenders Act 2003 (Qld); Dangerous Sexual Offenders Act 2006 (WA); Crimes (Serious Sex Offenders) Act 2006 (NSW); Serious Sex Offenders (Detention and Supervision) Act 2009 (VIC).

4. For example, a variant of the Static-99, the Automatic Sexual Recidivism Scale employed in New Zealand, which uses seven of the ten items from the Static-99 is computer scored.

5. This is true only insofar as it is based on conviction rates.

6. The Macquarie Dictionary defines cogent as: compelling assent or belief, convincing.

7. It has been argued that this type of statistical analysis is contorted since actuarial tests do not produce dichotomous results without invoking a “arbitrary” cut-off score and that predicting of risk, as distinct from prediction of recidivism necessarily requires a determination of probability as distinct from consideration of sensitivity, specificity and the types of decisions involved in determining recidivism. This argument ignores that the courts have to make a binary decision and conflates predictions of recidivism with the consequences of recidivism.

8. Although the location of the study is not mentioned in the article one of the authors, J. Dwyer, has personally communicated the location to the author.