Outcomes research offers out-of-hospital medicine a valuable methodology for studying the effectiveness of services provided in the out-of hospital setting. A clear understanding of the history and constructs of outcomes research is necessary for its integration into emergency medical services research. This report describes the conceptual framework of outcomes research and key methodological considerations for the successful implementation of out-of-hospital outcomes research. Illustrations of the specific applications of outcomes research and implications to existing methodologies are given, as well as suggestions for improved interdisciplinary research.