Reliability and validity of general health questionnaire (GHQ-12) for male tannery workers: a study carried out in Kanpur, India

BACKGROUND: The purpose of this study was to test the reliability, validity and factor structure of GHQ-12 questionnaire on male tannery workers of India. We have tested three different factor models of the GHQ-12. METHODS: This paper used primary data obtained from a cross-sectional household study of tannery workers from Jajmau area of the city of Kanpur in northern India, which was conducted during January-June, 2015, as part of a doctoral program. The study covered 286 tannery workers from the study area. An interview schedule containing GHQ-12 was used for tannery workers who had completed at least 1 year at their present occupation preceding the survey. To test reliability, Cronbach's alpha test was used. The convergent test was used for validity. Confirmatory factor analysis was used to compare three factor structures for the GHQ-12. RESULTS: A total of 286 samples were analyzed in this study. The mean age of the tannery workers in this study was 38 years (SD = 1.42). We found the alpha coefficient to be 0.93 for the complete sample. The value of alpha represents the acceptable internal consistency for all the groups. Each item of scale showed almost the same internal consistency of 0.93 for the male tannery workers. The correlation between factor 1 (Anxiety and Depression) and factor 2 (Social Dysfunction) was 0.92. The correlation between factor 1 (Anxiety and Depression) and factor 3 (Loss of confidence) was the highest 0.98. Comparative fit index (CFI) estimate best-fitted for model-III that gave the CFI value 0.97. The SRMR indicator gave the lowest value 0.031 for the model-III. CONCLUSIONS: The findings suggest that the Hindi version of GHQ-12 is a reliable and valid tool for measuring psychological distress in male tannery workers of Kanpur city, India. Study found that the model proposed by the Graetz was the best fitted model for the data.