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Precision of actuarial risk assessment instruments: Evaluating the ‘margins of error’ of group v. individual predictions of violence

  • Stephen D. Hart (a1), Christine Michie (a2) and David J. Cooke (a3)

Abstract

Background

Actuarial risk assessment instruments (ARAIs) estimate the probability that individuals will engage in future violence.

Aims

To evaluate the ‘margins of error’ at the group and individual level for risk estimates made using ARAIs.

Method

An established statistical method was used to construct 95% CI for group and individual risk estimates made using two popular ARAIs.

Results

The 95% CI were large for risk estimates at the group level; at the individual level, they were so high as to render risk estimates virtually meaningless.

Conclusions

The ARAIs cannot be used to estimate an individual's risk for future violence with any reasonable degree of certainty and should be used with great caution or not at all. In theory, reasonably precise group estimates could be made using ARAIs if developers used very large construction samples and if the tests included few score categories with extreme risk estimates.

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Copyright

Corresponding author

Professor Stephen D. Hart, Department of Psychology, Simon Fraser University, 8888 University Drive, Burnaby, British Columbia, Canada V5A 1S6. Email: hart@sfu.ca

Footnotes

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Declaration of interest

None. Funding detailed in Acknowledgements.

Footnotes

References

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Agresti, A. & Coull, B. A. (1998) Approximate is better than ‘exact’ for interval estimation of binomial proportions. American Statistician, 52, 119126.
Brown, L. D., Cai, T. T. & DasGupta, A. (2001) Reply to comments on ‘Interval estimation for a binomial proportion.’ Statistical Science, 16, 128133.
Faigman, D. L. (1995) The evidentiary status of social science under Daubert: Is it ‘;scientific’, ‘technical’, or ‘other’ knowledge? Psychology, Public Policy, and Law, 1, 960971.
Grisso, T. & Appelbaum, P. S. (1992) Is it unethical to offer predictions of future violence? Law and Human Behavior, 16, 621633.
Hajek, A. (2003) Interpretations of probability. In The Stanford Encyclopedia of Philosophy (ed. Zalta, E. N.). http://plato.stanford.edu/entries/probability-interpret.
Hájek, A. & Hall, N. (2002) Induction and probability. In The Blackwell Guide to the Philosophy of Science (eds Machamer, P. & Silberstein, M.), pp. 149172. Blackwell.
Hanson, R. K. & Thornton, D. (1999) Static 99: Improving Actuarial Risk Assessments for Sex Offenders. Ministry of the Solicitor General of Canada.
Hart, S. D. (1998) The role of psychopathy in assessing risk for violence: Conceptual and methodological issues. Legal and Criminological Psychology, 3, 123140.
Hart, S. D. (2001) Assessing and managing violence risk. In HCR-20 Violence Risk Management Companion Guide (eds Douglas, K. S., Webster, C. D., Hart, S. D., et al), pp. 1325. Burnaby, British Columbia: Mental Health, Law, and Policy Institute, Simon Fraser University, and Department of Mental Health Law and Policy, Florida Mental Health Institute, University of South Florida.
Hart, S. D. (2003) Actuarial risk assessment. Sexual Abuse: A Journal of Research and Treatment, 15, 383388.
Heilbrun, K. (1992) The role of psychological testing in forensic assessment. Law and Human Behavior, 16, 257272.
Henderson, R. & Keiding, N. (2005) Individual survival time prediction using statistical models. Journal of Medical Ethics, 31, 703706.
Janus, E. S. (2000) Sexual predator commitment laws: Lessons for law and the behavioral sciences. Behavioral Sciences and the Law, 18, 521.
Litwack, T. R. (2001) Actuarial versus clinical assessments of dangerousness. Psychology, Public Policy, and Law, 7, 409433.
Mackay, R. D., Colman, A. M. & Thornton, P. (1998) The admissibility of expert psychological and psychiatric testimony. In Analysing Witness Testimony: Psychological, Investigative, and Evidential Perspectives (eds Shepard, E., Heaton-Armstrong, A. & Wolchover, D.), pp. 321334. Blackstone.
Maden, T. & Tyrer, P. (2003) Dangerous and severe personality disorders: a new personality concept from the United Kingdom. Journal of Personality Disorders, 17, 489496.
Meehl, P. E. (1998) The Power of Quantitative Thinking. Paper presented at the annual meeting of the American Psychological Society Washington, DC. http://www.tc.umn.edu/~pemeehl/PowerQuantThinking.pdf
Melton, G. B., Petrila, J., Poythress, N., et al (1997) Psychological Evaluations for the Courts: A Handbook for Attorneys and Mental Health Professionals, 2nd ed. Guilford.
Monahan, J. A., Steadman, H. J., Appelbaum, P. S., et al (2005) Classification of Violence Risk (COVR). Psychological Assessment Resources.
Mossman, D. (2006) Another look at interpreting risk categories. Sexual Abuse: A Journal of Research and Treatment, 18, 4163.
Quinsey, V. L., Harris, G. T., Rice, M. E., et al (1998) Violent Offenders: Appraising and Managing Risk. American Psychological Association.
Szmukler, G. (2001) Violence risk prediction in practice. British Journal of Psychiatry, 178, 8485.
Tyrer, P. (2004) Getting to grips with severe personality disorder. Criminal Behaviour and Mental Health, 14, 14.
Wilson, E. B. (1927) Probable inference, the law of succession, and statistical inference. Journal of the American Statistical Association, 22, 209212.
Zeedyk, M. S. & Raitt, F. E. (1998) Psychological evidence in the courtroom: critical reflections on the general acceptance standard. Journal of Community and Applied Social Psychology, 8, 2339.

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Precision of actuarial risk assessment instruments: Evaluating the ‘margins of error’ of group v. individual predictions of violence

  • Stephen D. Hart (a1), Christine Michie (a2) and David J. Cooke (a3)

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