Study: Tools to assess crime risk for young cohorts are likely to fail over time if they ignore social change

Risk assessment instruments (RAIs) are widely used to inform high-stakes decision-making in the criminal justice system and other areas, such as health care and child welfare. These tools typically assume a relation between predictors and outcomes that does not vary with time. But because societies change, this assumption may not hold in all settings, generating what a new study calls cohort bias—a bias resulting from cohort-wide influences not experienced by past or future cohorts.