Abstract

Scales used in Substance Use Disorder (SUD), Drug User Quality of Life Scale (DUQOL) are not comparable because of different number of dimensions covered, different number of items, different values of K, scoring methods, etc. giving rise to different unknown distributions of scale scores and score ranges. Moreover, such scales suffer from methodological limitations. The paper suggests transforming raw item scores to normally distributed scores for meaningful arithmetic aggregation to get Scale score (S-score) reflecting severity of SUD and QoL scores to reflect overall QoL status. Parameters of normally distributed S-scores and QoL scores can be found from data. Normality of S-scores or QoL scores offer significant benefits including testing of statistical hypothesis across demographic variables by t-ratios, ANOVA, F-test, etc. Ranking of the factors, quantification of responsiveness of scales, comparison of progress/ deterioration path of different types of SUD through longitudinal data and better measures of reliability and validity adds to the benefits. Analysis incorporating categorical dependent variables for drug use can be undertaken by Multilevel analysis to find effects of interactions of cross-levels like School X Individual X Classroom or by Covariance structure analysis. Future studies suggested.

Keywords: Substance use disorder; Quality of life; Normal distribution; Test of hypothesis; Reliability; Validity