Research methods: beyond the clinical trial.

Emergency medicine differs from other specialties in that it has few restrictions in terms of pathology or patient group but is instead defined by time, with patients being selected on the basis of urgency. The important research questions generated by emergency medicine are therefore often complex and relate to organizational, economic, or social issues. Clinical trials have a limited role to play in these circumstances, and concepts such as the hierarchy of evidence might be unhelpful if the best methodology is not appropriate to the research question. Emergency medicine researchers therefore need to be prepared to use a wide range of methods, often in combination and often drawing on the social sciences. This article will introduce readers to methods from clinical epidemiology, operational research, health economics, and qualitative research, discussing the value of these approaches and identifying potential pitfalls.