Reliability and validity of the work role functioning questionnaire (Spanish version)

PURPOSE: Recently, the cross-cultural adaptation of the Work Role Functioning Questionnaire to Spanish was carried out, achieving satisfactory psychometric properties. Now we examined the reliability and validity of the adapted [Work role functioning questionnaire-Spanish version (WRFQ-SpV)] in a general working population with and without (physical and mental) health issues to evaluate its measurement properties. METHODS: A cross-sectional study was conducted among active workers. For reliability, we calculated Cronbach alphas to assess 'internal consistency', and the standard error of measurement (SEM) to evaluate 'measurement error'. We assessed the 'structural validity' through confirmatory factor analyses and 'construct validity' by means of hypotheses testing. The consensus-based standard for the selection of health status measurement instruments (COSMIN) taxonomy were used in the design of the study. RESULTS: A total of 455 workers completed the questionnaire. It showed excellent internal consistency (alpha = 0.98). The SEM for the overall scale was 7.10. The original five factor structure reflected fair dimensionality of the construct (Chi square, 1,445.8; 314 degrees of freedom; root mean square error of approximation = 0.08; comparative fit index >0.95 and weighed root mean residual >0.90). For construct validity, all hypotheses were confirmed differentiating groups with different jobs, health conditions and ages. Moderate to strong correlations were found between WRFQ-SpV and a related construct (work ability). CONCLUSIONS: Our study provides evidence of the reliability and validity of the WRFQ-SpV to measure health-related work functioning in day-to-day practice and research in occupational health care and the rehabilitation of disabled workers. It should be useful to monitor improvements in work functioning after implementing rehabilitation and/or accommodation programs. Longitudinal studies are needed to assess the responsiveness of the questionnaire