Construct Validity of WHOQOL-100 with Rasch Analysis

Message:
Abstract:
Introduction
Given the importance of measuring quality of life, as an important outcome for evaluating the health status of individuals as well as assess response to interventions, the need to examine the psychometric characteristics of this questionnaire is evident. In this study the structural validity of the WHOQOL-100 questionnaire, using Rasch analysis has been studied.
Method
Population examined in this study included 500 people from physically- movement disabled community that has been selected of Crescent Comprehensive Rehabilitation Center of Tehran. Participants in this study received the WHOQOL-100 questionnaire, which contain 6 subscales, and completed it. Then analysis was performed using Rasch analysis. On each of the dimensions one model of Rasch family models, which is called partial credit model, was fitted and then suitability of the items was considered with using of standard item fit statistics and analysis of differential item functioning.
Findings
After removing four overall items and then fitting the models separately on each dimension, four items of 12 items of physical health dimension, 14 items of 24 items of mental health dimension, 11 items of 16 items of independence dimension, 7 items of 12 items of social communication dimension, 7 item of 27 items of health environment dimension and 2 items of 4 items of religion, mental status and personal beliefs dimension diagnosed improper and excluded of questionnaire. Reliability indices, including Psi and Cronbach's alpha, were respectively in (0.900, 0.644) and (0.576, 0.878) intervals.
Discussion
The remaining items in each of the dimensions of the WHOQOL-100 questionnaires have been correctly fitted model So they can measure only one aspect of quality of life. For all dimensions, the reliability index PSI, was larger than Cronbach's alpha index.
Language:
Persian
Published:
Social Welfare Quarterly, Volume:14 Issue: 54, 2014
Pages:
147 to 166
https://www.magiran.com/p1402973