Validity and reliability of the Persian version of health-labour questionnaire in Traffic Accident Injured Referring to Hospitals affiliated with Mashhad University of Medical Sciences

Background: Health- Labour Questionnaire (SF-HLQ) is a measurement instrument for collecting the quantitative data on the relationship between disease and functional status of individuals of productivity losses related to health problems in individuals with paid or unpaid work. Since road traffic injuries are the leading cause of death for disability in the world. In this regard, we aimed to report on validity and reliability of the Persian version of Health- Labour questionnaire in assessing Productivity losses of the Road Traffic Injuries. Methods: In this cross-sectional study, a sample of 30 injured of traffic accident referring to hospitals affiliated with Mashhad University of Medical Sciences were randomly selected. Samples were evaluated in 2 stages and have been interviewed following 1 month by using the health- labour questionnaire and their loss of productivity was calculated by telephone. Face and content validity was performed by 5 health management and economics specialists and 10 students of Masterchr('39')s Degree of Health Services Management and their opinions were applied.  To determine the content validity of the questionnaire, content validity ratio (CVR) and content validity index (CVI) were used, and to determine reliability, Coefficient Correlation Interclass (ICC) for quantitative variables and kappa coefficient of agreement were used to evaluate the reliability of the nominal questions and SPSS 21 software used for data analysis. Results: CVI and CVR were calculated at 0.79- 0.49, Respectively, which is acceptable for this questionnaire. Intra-class Correlation Coefficient and Confidence interval in both lost productivity and lost working day variables were 0.99 (0.98-0.99) and 0.96 (0.93-0.98) respectively. Kappa coefficient of agreement for nominal questions was 0.99. Conclusion: The results of this study showed that the translated version of the health-labour questionnaire had presented excellent validity and reliability in assessing productivity loss in traffic incident patients.