Setting priorities for waiting lists: defining our terms. Steering Committee of the Western Canada Waiting List Project.

In order to develop standardized measures to assess patients' relative priority for services for which there are waiting lists, it is essential that key terms be clearly defined. We propose that severity be defined as the degree or extent of suffering, limits to activities or risk of death; that urgency be defined as severity combined with considerations of the expected benefit and the natural history of the condition; that need be considered equivalent to urgency; and that priority be defined in terms of urgency (or need) with or without consideration of social factors.