ABSTRACT
Background: Measuring socioeconomic status (SES) as an independent variable is challenging, especially in epidemiological and social studies. This issue is more critical in large-scale studies on the national level. The present study aimed to extensively evaluate the validity and reliability of the Iranian SES questionnaire. Methods: This psychometric, cross-sectional study was conducted on 3000 households, selected via random cluster sampling from various areas in East Azerbaijan province and Tehran, Iran. Moreover, 250 students from Tabriz University of Medical Sciences were selected as interviewers to collect data from 40 districts in Iran. The construct validity and internal consistency of the SES questionnaire were assessed using exploratory and confirmatory factor analyses and the Cronbach's alpha. Data analysis was performed in SPSS and AMOS. Results: The complete Iranian version of the SES questionnaire consists of 5 factors. The Cronbach's alpha was calculated to be 0.79, 0.94, 0.66, 0.69, and 0.48 for the occupation, self-evaluation of economic capacity, house and furniture, wealth, and health expenditure, respectively. In addition, the confirmatory factor analysis results indicated the data's compatibility with the 5-factor model (comparative fit index = 0.96; goodness of fit index = 0.95; incremental fit index = 0.96; root mean square error of approximation = 0.05). Conclusion: According to the results, the confirmed validity and reliability of the tool indicated that the Iranian version of the SES questionnaire could be utilized with the same structure on an extensive level and could be applicable for measuring the SES in a broader range of populations.
ABSTRACT
BACKGROUND: The aim of present study was to develop and validate an appropriate socioeconomic status (SES) assessment questionnaire to be used through health studies in Iranian urban households. METHODS: The study was conducted through a mixed method study design in Tabriz, northwest of Iran in 2014. It was conducted in several stages including: development of initial version, qualitative study, feasibility evaluation, and assessment of the validity as well as the reliability. The internal consistency, test-retest reliability, content validity, concurrent validity and construct validity were assessed. RESULTS: With respect to the assessment of construct validity, 5 domains (factors) were extracted includ-ing: main factor (α=0.84), self-evaluation of expenditure capacity (α=0.96), wealth (α=0.70), home and furniture (α=0.66) and costs related to health (α=0.55). Intraclass correlation coefficient was above 0.6 for all factors except for wealth domain. CONCLUSION: The questionnaire developed appeared to be a valid and reliable SES assessment tool. It may be of value to be used not only as a complementary questionnaire in most health surveys or clini-cal studies, but also as a main questionnaire in health equity and health economics research.
