AbstractThis article presents the case for the need for a re‐think in the prevailing orthodoxy of measurement approaches in the governance and management of public services. The article explores the simplification of complex reality that outcomes‐based performance management (OBPM) requires in order to function, and the consequences of such simplification. It examines the evidence for and against the effectiveness of OBPM, and argues that both sets of evidence can be brought into a single explanatory story by understanding the theory of OBPM. The simplification required to measure and attribute ‘outcomes’ turns the organization and delivery of social interventions into a game, the rules of which promote gamesmanship, distorting the behaviour of organizations, managers and practitioners who undertake it.