The SF36 Version 2: critical analyses of population weights, scoring algorithms and population norms
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The SF36 Version 2 (SF36V2) is a revision of the SF36 Version 1, and is a widely used health status measure. It is important that guidelines for interpreting scores are available.
A population sample of Australians (n = 3015) weighted to achieve representativeness was administered the SF36V2. Comparisons between published US weights and sample derived weights were made, and Australian population norms computed and presented.
Significant differences were observed on 7/8 scales and on the mental health summary scale. Possible causes of these findings may include different sampling and data collection procedures, demographic characteristics, differences in data collection time (1998 vs. 2004), differences in health status or differences in cultural perception of the meaning of health. Australian population norms by age cohort, gender and health status are reported by T-score as recommended by the instrument developers. Additionally, the proportions of cases within T-score deciles are presented and show there are important data distribution issues.
The procedures reported here may be used by other researchers where local effects are suspected. The population norms presented may be of interest. There are statistical artefacts associated with T-scores that have implications for how SF36V2 data are analysed and interpreted.
KeywordsSF-36 Population norms Emic effects Health status Cultural differences Scoring weights
We would like to thank Mr Nick Marosszeky for his valuable comments on the manuscript.
This project was supported by a grant from the Community Care Branch, Australian Commonwealth Department of Health and Ageing, as part of the National Continence Management Strategy. The collection of data was carried out by the Population Research and Outcome Studies Unit, South Australian Department of Health. Dr Richard Osborne is supported in part by the Baker Trust, Buckland Foundation, the Arthritis Foundation of Australia, and by the National Health and Medical Research Council Career Development Award Population Health Fellowship.
Finally, our thanks go to those South Australians who gave their time to complete the questionnaire.
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