ON THE GENERALIZABILITY OF STATISTICAL EXPRESSIONS OF HEALTH-RELATED QUALITY-OF-LIFE INSTRUMENT RESPONSIVENESS - A DATA SYNTHESIS

Responsiveness statistics have been suggested as criteria for selectin g health-related quality of life (HRQoL) instruments or for calculatin g the required sample size. This paper raises questions about the stab ility of estimates of instrument responsiveness. The questions are exa mined by use of data synthesis. A literature search identified instanc es where two HRQoL instruments were used concurrently on two or more o ccasions. An effect size difference between the instruments was calcul ated. The distribution of the differences in the effect size between p airs of instruments used conjointly in different applications was used as an indicator of variation in responsiveness. The effect size for a ll possible published uses of generic and disease-specific HRQoL instr uments was also examined. Responsiveness was found to be subject to co nsiderable variation. Disease-specific instruments were found to be co nsistently more responsive than generic instruments. The authors sugge st use of responsiveness data should be restricted to expanding pilot study results.