His program of research focuses on improving outcomes for children with medical complexity (CMC) and their families. This includes defining who CMC are and how to best understand their needs. Cohen's team is developing, evaluating and disseminating a number of evidence-based interventions aimed at improving health outcomes of CMC, providing caregiving supports for families, and mitigating unnecessary healthcare expenditures. Cohen has also developed secondary, related research foci on paediatric hospital medicine and quality of child health practice and research.