CONTEXT The objective structured clinical examination (OSCE) is comprised of a series of simulations used to assess the skill of medical practitioners in the diagnosis and treatment of patients. It is often used in high-stakes examinations and therefore it is important to assess its reliability and validity. METHODS The published literature was searched (PsycINFO, PubMed) for OSCE reliability estimates (coefficient alpha and generalisability coefficients) computed either across stations or across items within stations. Coders independently recorded information about each study. A meta-analysis of the available literature was computed and sources of systematic variance in estimates were examined. RESULTS A total of 188 alpha values from 39 studies were coded. The overall (summary) alpha acr...