Abstract
BACKGROUND: Social support is a key factor in public health. Since the precise evaluation of it is critical, the current study has been developed to evaluate the psychometric properties of the MOS-SSS questionnaire's abbreviated form (MSSS-5-item) among the Iranian older adults. METHODS: This cross-sectional and methodological study was conducted on 420 community older adults (age ≥ 60) through random multi-stage sampling. The questionnaire was first translated into Persian through the Forward & Backward method based on WHO guidelines. Next, the validity of scales was investigated by calculating face validity, content validity, Known-group validity, explanatory factor analysis, and confirmatory factor analysis indices. The reliability of the questionnaire was calculated by internal consistency, test-retest, and absolute reliability. Moreover, the scalability of the questionnaire was checked through the Mokken scale analysis. The software packages SPSS version 22, AMOS version 22, and R (Mokken package) were employed to analyze the data. RESULTS: the face validity was conducted using interviews with older adults and gathering the specialists' opinions. Then, the items were grammatically and lexically corrected accordingly. The CVI index of the overall scale was 0.94, and for every single item above 0.89. The results of the independent t-test showed that the current questionnaire well distinguished between the older adults who do and do not feel lonely (p < 0.001). Two components were recognized according to the explanatory factor analysis. They together explained 67.78% of the total variance of the questionnaire. The CFA showed that the two-factor model had acceptable fit indices. The questionnaire had desirable internal consistency (α = 0.78), stability (ICC = 0.98), and absolute reliability (SEM = 0.56, MDC = 1.57). Furthermore, the Mokken scale proved that MSSS-5-item was a strong scale (H = 0.51, se = 0.03). CONCLUSION: The present study results showed that the MSSS-5-item questionnaire had suitable validity and reliability to be used among Iranian older adults.