Revision of the ICIDH Severity of Disabilities Scale by data linking and item response theory.
The Severity of Disabilities Scale (SDS) of the ICIDH reflects the degree to which an individual's ability to perform a certain activity is restricted. This paper describes the application of two models from item response theory (IRT), the graded response model and the partial credit model, in order to derive a tentative proposal for a revised SDS. The key ingredient of the approach is to scale existing disability items obtained in different studies on a common scale by exploiting the overlap. Both IRT models are fitted to a linked data set containing items for measuring walking disability. Based on these solutions, a tentative SDS is constructed. The paper concludes with a discussion of the implications, limitations and advantages of the approach.
TNO Prevention and Health, P.O. Box 2215, 2301 CE Leiden, The Netherlands. S.vanBuuren@pg.tno.nl
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Hopman-Rock
D000203:Activities of Daily Living / Q000145:classification*; D003625:Data Collection / Q000706:statistics & numerical data*; D004185:Disability Evaluation; D006801:Humans; D008432:Mathematical Computing; D015233:Models, Statistical; D010147:Pain Measurement / Q000706:statistics & numerical data