TESTS OF DATA QUALITY, SCALING ASSUMPTIONS, AND RELIABILITY OF THE DANISH SF-36

We used general population data (n = 4084) to examine data completenes s, response consistency, tests of scaling assumptions, and reliability of the Danish SF-36 Health Survey We compared traditional multitrait scaling analyses to analyses using polychoric correlations and Spearma n correlations. The frequency of missing Values was low, except for el derly people and people with lower levels of education. Response consi stency was high and compared well with results for the U.S. SF-36. For respondents with computable scales in all eight domains, scaling assu mptions (item internal consistency, item discriminant validity, equal item-own scale correlations, and equal variances) were satisfactory in the total sample and in all subgroups. The SF-36 could discriminate b etween levels of health in all subgroups, but there were skewness, kur tosis, and ceiling effects in many subgroups (elderly people and peopl e with chronic diseases excepted). Concerning correlation methods, we found interesting differences indicating advantages of using methods t hat do not assume a normal distribution of answers as an addition to t raditional methods. (C) 1998 Elsevier Science Inc.