Assessing convergent validity of health-state utilities obtained using different scaling methods.
A number of empirical studies have attempted to assess the convergent validity of health-state utilities obtained using two or more scaling methods (standard gamble, time tradeoff, rating scale, magnitude estimation, equivalence technique, and willingness-to-pay). The data from these studies can be mapped onto an N x K matrix, where N and K are the numbers of respondents and health states, respectively, and each matrix cell consists of a pair of health-state utilities, one obtained using scaling method X and the other obtained using scaling method Y. The Pearson's rassessing convergent validity can then be computed as 1) the unraveled correlation over all N x K data pairs, 2) the mean within-respondent correlation, 3) the mean within-health-state correlation, or 4) the correlation of the across-respondents means. These four different ways of computing the correlation do not necessarily yield the same results. The appropriateness of each method of computing the correlation is considered.
Nickerson
C A
CA
Section of General Medicine, Philadelphia Veterans Affairs Medical Center, The Division of General Internal Medicine, University of Pennsylvania School of Medicine, Philadelphia, USA. cnickers@s.psych.uiuc.edu
D003661:Decision Support Techniques; D006304:Health Status; D006801:Humans; D008962:Models, Theoretical; D015203:Reproducibility of Results