The predictive accuracy of the Risk Matrix 2000: A meta-analysis

Background. The Risk Matrix 2000 is a static actuarial tool designed for adult male sex offenders. It consists of three scales (Sex, Violence, and Combined) intended to assess risk for sexual, non-sexual violent, and any violent recidivism, respectively. Methods. This meta-analysis identified 16 unique samples (from 14 studies) that examined the extent to which the Risk Matrix 2000 scales discriminate recidivists from non-recidivists. Results/Conclusions. The three Risk Matrix 2000 scales significantly predicted all recidivism types (i.e., sexual, non-sexual violent, any violent, non-violent, and any recidivism). Effect sizes were generally comparable or higher than those found by Hanson and Morton-Bourgon (2009) for the Risk Matrix 2000 and for other actuarial scales designed for a similar purpose. The Sex scale provided the best predictive accuracy for sexual recidivism (d = .74). The Violence and Combined scales both predicted non-sexual violent recidivism and any violent recidivism with similarly large effect sizes. Although the scales were not designed to predict non-violent or any (including violent) recidivism, effect sizes for these outcomes were also moderate to large (d's exceeding .60). Effect sizes were significantly higher in the U.K. than in other countries, and low in samples of sex offenders preselected as unusually high risk or high need. These results support the use of the Risk Matrix in applied risk assessment practice. Additional research on the calibration of the Risk Matrix is needed.