Policy Evaluations

which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. This paper summarises the consequences of emergency department crowding. It provides a comparison of the scales used to measure emergency department crowding. We discuss the multiple causes of crowding and present an up-to-date literature review of the interventions that reduce the adverse consequences of crowding. We consider interventions at the level of an individual hospital and a policy level. 1