Purpose: The Work Role Functioning Questionnaire (WRFQ) is a tool developed in the United States to measure work disability and assess the perceived impact of health problems on worker ability to perform jobs. We translated and adapted the WRFQ to Spanish spoken in Spain and assessed preservation of its psychometric properties.
Methods: Cross-cultural adaptation of the WRFQ was performed following a systematic 5-step procedure: (1) direct translation, (2) synthesis, (3) back-translation, (4) consolidation by an expert committee and (5) pre-test. Psychometric properties were evaluated by administering the questionnaire to 40 patients with different cultural levels and health problems. Applicability, usability, readability and integrity of the WRFQ were assessed, together with its validity and reliability.
Results: Questionnaire translation, back translation and consolidation were carried out without relevant difficulties. Idiomatic issues requiring reformulation were found in the instructions, response options and in 2 items. Participants appreciated the applicability, usability, readability and integrity of the questionnaire. The results indicated good face and content validity. Internal consistency was satisfactory for all subscales (Cronbach's alpha between 0.88 and 0.96), except for social demands (Cronbach's alpha = 0.56). Test-retest reliability showed good stability, with intraclass correlation coefficients between 0.77 and 0.93 for all subscales. Construct validity was considered preserved based on the comparison of median scores for each patient group and subscale.
Conclusions: Our results indicate the cross-cultural adaptation of the WRFQ to Spanish was satisfactory and preserved its psychometric properties, except for the subscale of social demands, whose internal consistency should be interpreted with caution.