His research interests primarily lie within the fields of prisoner reentry and corrections, and how they intersect with public policy. His recent work investigates the impact of post-release reentry services upon recidivism, whether effects vary across different levels of programmatic quality, and how measurement strategies translate into different policy prescriptions within evaluation research. Ostermann has served as Principal Investigator on several federally funded grants that investigate research questions about evidence-based crime policy, and include partnerships with practitioners and other criminal justice stakeholders. His work has been published in Justice Quarterly, Journal of Research in Crime and Delinquency, Law and Human Behavior, Crime and Delinquency, Criminology and Public Policy, and other scholarly outlets.