Individualization in quality of life measurement: instruments and approaches.

Quality of life (QOL) and health-related QOL (HRQOL) instruments abound in the health care literature, but many appear to measure nothing more than what in previous decades was called health status. As such, they fail to include numerous domains of life that are salient to many people, they omit items tapping into meaning and feelings of well-being, and they do not allow for individualization to take into account personal preferences. Based on a conceptualization of QOL and a corresponding 2-dimensional scheme for classification of instruments, several measures published in the literature are presented that allow for subject selection of domains, specification of standards and aspirations, and/or report of subjective reactions to status on various domains. The advantages and disadvantages of standardized versus individualized instruments are discussed, as well as methodologic questions with respect to the latter that future research needs to address.