The invention of the Objective Structured Clinical Examination (OSCE) represented a radical break with forms of examination traditionally used to assess the competence of medical students. Unlike written or bed-side exams, an OSCE required students to perform with a series of actors in fixed-interval simulated scenarios. The technique spread rapidly and today OSCEs are used around the globe to assess health professionals. This Foucauldian socio-history explores how discourses of performance, psychometrics and production have legitimized the widespread adoption of OSCEs. Probing an archive of over 600 published articles, interviews with 25 key informants in Europe and America and visits to key universities and testing organizations, the author documents how these discourses have led to substantial changes in the way competence is understood. This book will interest those concerned about the ethical dimensions of assessment and the intersection of examination, equity, globalization and social control.