The advantage of multiple measures of quality of life.

The concept of "quality of life" is rich and multi-faceted. In the present paper, we argue that the very richness of the concept requires that we (a) evaluate multiple dimensions of quality of life in our studies and (b) include multi-item assessments of each dimension selected for study. Conceptual and psychometric advantages which accrue by using multiple measures are delineated. We discuss the way in which the use of multiple measures affects the selection of instruments, the source of information, and the mode of data collection. In addition, the application of multi-item assessments to the construction of health status indices is considered along with their use in health policy and cost-benefit analyses.