The conceptualization and measurement of quality of life in older adults: a review of empirical studies published during 1994-2006.

Instruments with acceptable measurement properties that support their application to older adults across a range of settings need to be identified. A narrative literature review of empirical studies investigating the conceptualization and measurement of quality of life (QoL) among older adults from 1994 to 2006 was performed. The review focused on evidence provided for conceptual frameworks, QoL definitions, types of measurements utilized and their psychometric properties. Two searches were conducted. The first search conducted in 2004 used Cinahl, Medline, PsycInfo, Embase and Cochrane databases. A supplemental search was conducted in December 2006, which included these bases from 2004 to 2006, and Sociological Abstracts and Anthropological literature base. The review included 47 papers. A total of 40 different measurements were applied in the studies, assessing most frequently functional status and symptoms. The most extensive psychometric evidence was documented for the SF-36. Although construct validity was reported in the majority of studies, minimal empirical evidence was given for other psychometric properties. Further, 87% of the studies lacked a conceptual framework and 55% did not report any methodological considerations related to older adults. Quality control standards, which can guide measurement assessment and subsequent data interpretation, are needed to enhance more consistent reporting of the psychometric properties of QoL instruments utilized. Future work on the development of common QoL assessment models that are both person-centered, causal and multidimensional based on collaborative efforts from professionals interested in QoL from the international gerontological research community are needed.