Psychometric properties of the Life Satisfaction Index version A (LSIA) among older adults in Iran

Background One of the most important indicators of mental health in old age is life satisfaction. We aimed at verifying the psychometric properties of the Life Satisfaction Index-A (LSIA), used to evaluate life satisfaction and well-being, among older Iranians. Methods The forward-backward procedure was used for translating the English version of the LSIA into Persian. Thereafter, face and content validity were done by 15 specialists. Confirmatory factor analysis (CFA) was done for construct validity. Reliability was evaluated by using the Cronbach's alpha method. Statistical analysis was performed using Mplus 7.4. p<0.05 was considered statistically significant. Results In the face validity, more than 90% of all questions had an impact score above 1.5, content validity ratio (CVR) >0.6, and content validity index (CVI) >0.8. CFA showed that the first-level factors 'resolution and fortitude', 'Zest' and 'congruence between desired and achieved goals in life' explain the first factor of the second level which is 'the perception of reality', and the first level factors 'positive self-concept' and 'mood tone' explain the second factor of the second level which is 'mental perception'. The proposed structural model showed acceptable to the data and Cronbach's alpha for the LSIA's dimensions ranged between 0.89 and 0.95. Conclusion The findings suggest that the LSIA appears to be an appropriate instrument for older adults in Iran, but it needs further validation to explore different sub-cultural aspects in the older Iranian population.