The Chestnut Health Systems Hub is comparing the effectiveness of the Recovery Management Checkups (RMC) model, an evidence-based intervention that provides regular, fixed schedule checkups to support treatment retention and recovery, with an adaptive model (RMC-Adapted) that tailors checkup frequency and intensity to individuals’ needs. Each condition offers justice-involved individuals referral or assertive linkage to a designated treatment provider upon release from jail. The study will be conducted in six county jails across Illinois, with the goal of increasing linkage to and retention in evidence-based treatment in the community, while reducing relapse and recidivism.