Translation and validation of the " Uncertainty in Illness Scale" in Iranian Patients with Cancer

Objective (s): To translate and validate the “Mishel’s Uncertainty in Illness Scale-Adult Form” (MUIS-A) in Iranian cancer patients. The scale was translated into Persian and back translated into English and revised according to the comments of the scale designers. Then، content and face validity، construct validity، internal consistency reliability and stability of the Persian version were measured. Data were analyzed using SPSS version 16 and LISREL 8. 5. In all 420 cancer patients completed the questionnaire. The mean score for the MUIS-A was 90. 1 (16. 8). Confirmatory factor analysis showed satasfactory results for the whole instrument and its four subscales. The stabilty of the instrument with a three-week interval was 0. 91. Cronbach''s alpha was 0. 89 for the whole scale of 32 MUIS-A items and α ranged from 0. 58 to 0. 86 for its four factors. The Persian version of the MUIS-A has good validity and reliability indices. It can be used to assess uncertainty in illness in Iranian patients with cancer.