Deriving utility scores from the SF-36 health instrument using Rasch analysis
Graeme Hawthorne, Konstancja Densley, Julie F Pallant, Duncan Mortimer, Leonie Segal
QUALITY OF LIFE RESEARCH | SPRINGER | Published : 2008
BACKGROUND: Utility scores for use in cost-utility analysis may be imputed from the SF-36 health instrument using various techniques, typically regression analysis. This paper explored imputation using partial credit Rasch analysis. METHOD: Data from the Assessment of Quality of Life (AQoL) instrument validation study were re-analysed (n = 996 inpatients, outpatients and a community sample). For each AQoL item, factor analysis identified those SF-36 items forming a unidimensional scale. Rasch analysis located scale logit scores for these SF-36 items. The logit scores were used to assign AQoL item scores. The standard AQoL scoring algorithm was then applied to obtain the utility scores. RESUL..View full abstract
The research reported in this paper was supported by an Australian National Health and Medical Research Council (NHMRC) Project Grant, the Department of Psychiatry in the Faculty of Medicine, Dentistry and Health Sciences at The University of Melbourne and the Centre for Health Economics at Monash University. Much of this work was completed while Professor Leonie Segal was working at the Centre for Health Economics at Monash University prior to taking up her current position as the Professor of Health Economics, Division of Health Sciences, University of South Australia. The views expressed herein are the sole responsibility of the authors. The authors have no competing interests to declare.