Satyendra Nath Chakrabartty*
Objectives: To review methodological issues of disability measuring tools (DMTs) and Health-related Quality of life (HRQoL) and to transform item-scores and health-profiles to continuous scores satisfying desired properties
Method: Using data driven weights, item score are converted to equidistant score (E) and value of Health-profile is obtained as weighted sum (Y). E-scores and Y-scores are standardized separately to Z-scores and further transformed to proposed scores (P) in [1, 100]. Scale score as sum of item-wise P-scores follow Normal distribution.
Results: P-scores offer better arithmetic aggregation, meaningful comparisons, relative importance of domains, predicting disability scores using HRQoL scores as predictors and statistical inferences for longitudinal or snap-shot data. Methods described to obtain responsiveness, theoretical reliability, factorial validity and equivalent scores of different scales.
Discussion: Proposed scores satisfying desired properties facilitate parametric analysis and computing psychometric concepts have theoretical advantages including meaningfulness of operations, better comparisons and use HRQoL scores as predictor of disabilities.
KeywordsQuality of Life; Likert item; Normal distribution; Reliability; Validity; Responsiveness
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