Generalizability of valuations on health states collected with the EuroQolc-questionnaire

Problem: Non-response and non-usable response were found in population surveys on valuation of health states. If non-response is selective regarding valuations, then generalization of the resulting values to the whole survey population is not permitted. This could limit the use of empirical utility values in resource allocation in health care. Methods: Response behaviour of a sample of 1400 from the Dutch general population to the mailed EuroQol^c-questionnaire was analyzed by four methods. I. Phoning resolute non-respondents; II. comparison of zip code characteristics of respondents and non-respondents (because individual data on background characteristics were not available for the non-respondents); III. analysis of response over time (wave-analysis); IV: comparison of background variables of successful (less than two valuations missing) and unsuccessful respondents, combined with analysis of the effect of these background variables on valuations. Results: No indications for selective non-response were found, although the phenomenon appeared hard to investigate. The successful response came from a slightly younger and better educated subsample. However, a general influence of age and educational level on valuations could not be shown. This finding is consistent with the literature. Conclusion: Although the existence of selective non-response cannot be excluded, its relevance can be considered to be small. This finding is encouraging for the use of empirical utility values in allocative decisions.