[Evaluation of life in the elderly (LWO): the validation of a measuring instrument]

The goal of this study is the adaptation and validation of the Dutch translation of Lawton's "Valuation of Life" scale. In developing this scale Lawton et al. argued that the usual health related quality of life scales had a limited contribution in explaining health utility and desired length of life and that the "Valuation of Life" is intended to cover a specific quality of life domain not related to health. The translated scale has been implemented in the 4th observation of the Longitudinal Aging Study Amsterdam (LASA) in 2001-2002. In total 1139 respondents between 65 and 95 years old reacted to the written questionnaire. After extensive structural analyses of the data we concluded that the Dutch version of the scale could be reduced from the original 19-item to a 12-item scale. In addition this scale could be divided in three 4-items-subscales, clearly labelled as Resilience, Ambition and Vitality. The new scale as well as the subscales hardly overlap with the data of two health related quality of life scales while the overlap with the more or less objective health measures (discriminant validity) remains limited. It appears that the Dutch "Valuation of Life" scale is to a certain extend related to other positive affect measures as Self evaluation, Mastery and Self-efficiency (concurrent validity). For the moment we agree that the Dutch scale measures an important and specific domain of quality of life without any reference to health issues in the scale. Whether these data contribute in explaining health utility and desired length of life remains to be demonstrated in another publication.