Alice in actuarial-land: through the looking glass of changing Static-99 norms

The Static-99, an actuarial rating method, is employed to conduct sexual violence risk assessment in legal contexts. The proponents of the Static-99 dismiss clinical judgment as not empirical. Two elements must be present to apply an actuarial risk model to a specific individual: sample representativeness and uniform measurement of outcome. This review demonstrates that both of these elements are lacking in the normative studies of the Static-99 and its revised version, the Static-99R. Studies conducted since the publication of the Static-99 have not replicated the original norms. Sexual recidivism rates for the same Static-99 score vary widely, from low to high, depending on the sample used. A hypothetical case example is presented to illustrate how the solitary application of the Static-99 or Static-99R recidivism rates to the exclusion of salient clinical factors for identifying sexual dangerousness can have serious consequences for public safety.