Recent National Health Service (NHS) structural and policy changes have brought with them shifts in the ideals, pace, and physical location of work, with significant consequences for staff. Hospital nurses have experienced increased devolution of managerial responsibility and are under pressure to effect a faster throughput of more acutely ill patients and simultaneously contain service costs. Community nurses have experienced similar pressures, with those providing mental health and learning disability services radically reconceptualising the nature of their work to support non-institutional living (Adams et al. 1998). Nurses' work pressure has been further exacerbated by the removal of student labour due to educational changes (United Kingdom Central Council for nursing, midwifery and health visiting (UKCC) 1986). This has resulted in a lower ratio of qualified to unqualified nurses in the NHS and a static number of qualified nurses compared with a previous upward trend of approximately 4 per cent annually since 1976 (Buchan et al. 1998).

This paper describes the theoretical and methodological perspectives adopted by a multidisciplinary research group undertaking a government-funded evaluation of a United Kingdom innovation in the continuing care of elderly people. In 1983 three experimental National Health Service (NHS) nursing homes were set up to care for patients usually cared for in NHS geriatric hospitals. Drawing on different approaches to the evaluation of health-care innovations, this paper delineates an evaluation model which identifies four types of variables: structure, process, intermediate outcome and final outcome. The relationship of this model to the design of an evaluation comprising seven complementary research activities is described, emphasising the need for multiple perspectives and multiple methods in policy-oriented health-care evaluations.