Construct and Psychometric Properties of a New Version Quality of Life Scale Based on Choice Theory

Choice theory, as a psychopathological model, postulated five basics, genetically and universally, needs. Accordingly, the rate of everybody happiness and quality of life is depended on the number of his needs fulfilling. Although some scales have been constructed to assess basic needs, they have proposed unity of needs for all human. The present study was designed to construct a new scale, considering individualisation needs for each person; quality of life scale based on choice theory (QOLSCT). Using cluster sampling, six hundred (49% female and 51% male) postgraduate students were selected. One hundred fifty participants also filled SF-36 and GHQ, and 80 participants refilled QOLSCT with four weeks' interval again. Cronbach's alpha, split-half and test re-test (one month) reliability scores were 0.78, 0.75, and 0.92 successively. The correlation between items and total scores range from 0.36 to 0.72, all with P values ≥ 0.0001. Confirmatory factor analysis showed satisfactory values of goodness-of-fit indices, RMSEA, CFI, NFI and GFI were, 0.05, 0.99, 0.99 and 0.99 respectively. Convergent and divergent validity also showed significant correlations. The result of the present study showed that the new version of quality of life scale based on choice theory could be confirmed. The good level of reliability, fairly goodness of fit indexes, and very good convergent validity support this idea.