Subjective quality of life measures for evaluating medical intervention

Medical interventions are usually evaluated in terms of mortality and morbidity data, but there is recent interest in going beyond medical data to assess the impact of the therapy on the objective and subjective quality of the patient's life. Objective quality of life measures such as employment and functional status are relatively straightforward, but measuring subjective quality of life is a more complex task. This article reviews psychometric issues relevant to using subjective quality of life scales developed by Bradburn and by Campbell, Converse, and Rodgers for research with patient populations. The evidence indicates that these relatively brief scales assess both affective and cognitive aspects of subjective quality of life, that they are measuring something more stable than mood but less enduring than personality, and that they can be as sensitive as physiological measures in distinguishing among treatment groups. It is concluded that these scales offer a useful complement to more objective measures of patient status for research evaluating medical interventions.