Translation and Psychometric Properties of Persian Version of Independent Living Scale in Patients with Schizophrenia

Background Independent living skills are major targets for rehabilitation in patients with schizophrenia. So, assessment of their performance is required to obtain valuable information for planning intervention. The independent living scale (ILS) is a useful assessment tool for this population. Objectives The aims of this study were to translate the three of five subscales of ILS (“memory/orientation”, “health and safety” and “social adjustment”) into Persian language and evaluate their validity. The remaining two subscales of ILS (“money management”, “home management and transportation”) have already been translated to Persian language by other researchers in Iran. In addition, the reliability of whole Persian version of ILS subscales was evaluated to be used for patients with Schizophrenia. Methods The three subscales of ILS were translated from English into Persian according to the international quality of life assessment (IQOLA) approach. The translation of the three subscales: memory/orientation, health and safety and social adjustment, were analyzed by experts to develop the final version of each subscale. After translation, face and content validity of scale were performed. In face validity evaluation, the scale was investigated by 6 occupational therapists in terms of simplicity, mastery, relationship and clarity or transparency for each of the items. To assess the validity of content, scale was examined by 15 occupational therapists and content validity ratio (CVR) and content validity index (CVI) of each item were calculated. To assess the reliability of the subscales, test-retest reliability techniques (intraclass correlation coefficient (ICC) and standard error of measure (SEM) were utilized. Results The simplicity, relevance, clarity and necessity of the translated items were acceptable, according to the CVI and CVR scores. Face validity was also acceptable with respect to agreement rate (> 80%). Test-retest reliability was acceptable with respect to ICC and SEM scores. The values of the ICC were > 0.70 and the values of the SEM were ≤ 1 for the score of subscales and total score. Conclusions The Persian version of the ILS has acceptable levels of face validity, content validity, and test-retest reliability to use for Iranian patients with Schizophrenia.