Evidence for risk estimate precision: implications for individual risk communication

Actuarial risk assessment instruments using well-established predictor variables measured at the individual level (e.g., age, criminal history, psychopathy) discriminate well between recidivists and non-recidivists across diverse samples. Data indicating the relative risk of recidivism can inform policy decisions about allocating resources according to risk within a correctional system, consistent with the first of the risk-need-responsivity (RNR) principles. Evidence for the precision of absolute risk as applied to an individual based on scores from many samples, however, has proven challenging. In this paper, we present a study examining the association of actuarial risk estimate precision with sample size using the Post Conviction Risk Assessment (PCRA; Lowenkamp et al., 2013), in samples of up to 26,642 offenders. Results indicate that the precision of individual estimates can be demonstrated with sufficient sample size. We believe that the implications of absolute risk for the communication of an individual offender's risks have been poorly understood. We argue that the purpose of individual-level risk communication is to ensure the effective application of policy, which requires matching a new case to aggregate data. We illustrate how an offender's risk might thus be communicated, and conclude that this function is distinct from management of an individual's criminogenic needs and identification of effective and suitable treatments.