Assessing the quality of life--reality or impossible dream? A discussion paper.

Many now claim that maintaining or improving the quality of life is the essence of healthcare (i.e. care and/or treatment that improves the patients' quality of life). Interest in QL, however, stems from increasing recognition that individuals are an integrated whole rather than a series of disconnected parts or disease states. Though this represents a significant change from the past--when the emphasis lay solely on physical or medical condition--it is not, in itself, meaningful unless reliable and valid ways of evaluating the human aspects of the experience can be identified (i.e. quality of life). As quality of life (QL) is seen as a positive state, a desirable outcome of healthcare interventions, it has gained credence as an appropriate outcome measure and has intuitive appeal. Indeed, it is suggested that, because of its close relationship to mortality, self-perceived QL may be the most important outcome of both acute and, particularly, chronic disease. Lack of consensus about its meaning has, however, resulted in ambiguity and, therefore, difficulties in its measurement reflecting, in turn, the difficulty in identifying the components of this multifaceted concept. This paper explores these issues and questions whether we are, in fact, attempting to measure something that cannot truly be measured.