Loneliness is usually a chronic condition which may lead to physical and psychological undesirable consequences, and requires measurement and intervention. This study was conducted with the aim of preparing a Persian version of the 11-item de Jong Gierveld Loneliness Scale and evaluating its psychometric properties among the Iranian older adults. After applying the translation-back translation method, the prepared script was subjected to the face and content validity evaluations and a Persian version of the scale was prepared. Factor analysis, concurrent validity, internal consistency, and test-retest methods were used to validate the scale. The Persian version of the 11-item de Jong Gierveld Loneliness Scale showed acceptable content validity. The negative and significant correlations between the loneliness scores and the Philadelphia Geriatric Center Morale Scale indicated that the questionnaire had acceptable concurrent validity. The results of confirmatory factor analysis confirmed two factors for the scale. Also, the results of the intra-class correlation coefficient and Cronbach's alpha coefficient demonstrated that the scale had acceptable reliability. The Persian version of the 11-item de Jong Gierveld Loneliness Scale is an appropriate tool for measuring loneliness in the Iranian older adults.
Keywords: De Jong Gierveld Loneliness Scale; loneliness; older adults; psychometrics; validation.