Mass incarceration is commonly understood as a sweeping national policy development, which has obscured remarkable local variation at the policy implementation stage. California’s “Realignment” (Assembly Bill [AB] 109; 2011) is a reform that exploits this variation by design. Research consistently finds that, net of crime, demographic, political, and system capacity characteristics explain the variation in incarceration across local jurisdictions. Do these characteristics also explain decarceration? This study uses group-based trajectory modeling and logistic regression to examine the association of such characteristics with California county trajectories of state prison use in the decade preceding Realignment. County imprisonment trajectories and their related characteristics are then assessed as explanations for decarceration under AB 109. Distinct “risk” factors for high and/or increasing imprisonment trajectories are identified, as well as apparent protective factors. A clear association was found between previous trajectories and decarceration, but county-level characteristics did not demonstrate the predicted effects. Results indicate that decarceration cannot be explained as merely the mirror image of incarceration and should be examined as a distinct phenomenon. Implications for future research and policymaking are discussed.
(Publisher abstract provided.)