Objective: To evaluate how well quality of life is being measured in the medical literature and to offer a new approach to the measurement.
Data sources: Original English-language articles having the term "quality of life" in their titles were identified from a recent Quality-of-Life Bibliography and from two MEDLINE searches. Articles were eligible for review only if they described or used one or more "quality-of-life" instruments.
Study selection: Twenty-five articles were randomly selected from each of the three data sources.
Data extraction: Each article was reviewed for its compliance with two sets of criteria having several components, which are cited under "Data Synthesis."
Data synthesis: (1) Investigators conceptually defined quality of life in only 11 (15%) of the 75 articles; identified the targeted domains in only 35 (47%); gave reasons for selecting the chosen quality-of-life instruments in only 27 (36%); and aggregated their results into a composite quality-of-life score in only 27 (38%) of 71 eligible articles. (2) No article distinguished "overall" quality of life from health-related quality of life; patients were invited to give their own separate rating for quality of life in only 13 articles (17%); and among 71 eligible articles, patients were asked to supplement the stipulated items with personal responses in only nine (13%) and to rate the importance of individual items in only six (8.5%).
Conclusions: Because quality of life is a uniquely personal perception, denoting the way that individual patients feel about their health status and/or nonmedical aspects of their lives, most measurements of quality of life in the medical literature seem to aim at the wrong target. Quality of life can be suitably measured only by determining the opinions of patients and by supplementing (or replacing) the instruments developed by "experts."