This review compared the accuracy of various approaches to the prediction of recidivism among sexual offenders. On the basis of a meta-analysis of 536 findings drawn from 118 distinct samples (45,398 sexual offenders, 16 countries), empirically derived actuarial measures were more accurate than unstructured professional judgment for all outcomes (sexual, violent, or any recidivism). The accuracy of structured professional judgment was intermediate between the accuracy found for the actuarial measures and for unstructured professional judgment. The effect sizes for the actuarial measures were moderate to large by conventional standards (average d values of 0.67-0.97); however, the utility of the actuarial measures will vary according to the referral question and samples assessed. Further research should identify the psychologically meaningfully factors that contribute to risk for reoffending. (PsycINFO Database Record (c) 2009 APA, all rights reserved).