Content validity in the assessment of health status.

Content validity in the measurement of health status of individuals and population is a major problem in health needs assessment. This problem stems largely from the limited sampling inadequacy of the universe of empirical properties that represent the concept of health. In general, attempts to strengthen sensitivity of health status measures by defining health in very broad terms compromise specificity of measurement. Narrow definitions, on the other hand, may result in poor measurement validity and misclassification of subjects. This paper compares three basic paradigms of health: the medical model, the holistic model and the high-level wellness model, with respect to their content validity and therefore suitability for health status assessment.