Measuring overall health: an evaluation of three important approaches.

There is growing recognition that meaningful measures of health-related quality of life must be used to evaluate health care interventions. We examined the practicality and validity of three promising measures of overall health: the General Health Rating Index (GHRI), the Quality of Well-being Scale (QWB), and the Sickness Impact Profile (SIP). Practicality was assessed in terms of interviewer training required, administration time, and respondent burden. Content validity, convergent construct validity, and tests of discriminant validity were also evaluated. Although differing in theory and application, we found that each instrument performed according to the claims of the developers and could provide useful, valid data on overall health. The GHRI may be preferred where brief, self-administered forms are required; the QWB has advantages when health assessments are used to calculate cost-effectiveness; and the SIP is a versatile, easy to understand measure dealing with a wide range of specific dysfunctions. It is worth the required effort to include well-studied measures such as these in any trial intended to provide definitive information on the effectiveness of health care interventions.