Validation of the structural coherency of the General Health Questionnaire.

OBJECTIVE Investigate the structural coherency of the 60-item version of the General Health Questionnaire via exploratory and confirmatory factor analyses. METHOD The study design is a cross-sectional survey. A random sample of 146 individuals from the city of Divinópolis-MG volunteered to participate in the present study and responded to the 60-item version of the General Health Questionnaire adapted and validated for use in Brazil. Statistics consisted of exploratory and confirmatory factor analysis. Reliability was estimated using Cronbach's alpha method. RESULTS Alpha coefficients for all five content scales of the General Health Questionnaire were high (α > 0.8). For four of the five scales, a unifactorial model of constituent items provided a good fit to the data. Items comprising the fifth scale, Psychic Stress, exhibited a two-correlated factor structure. A factor analysis of scores for the five scales yielded strong evidence of coherency, with all scales loading substantially on a single common factor. CONCLUSION The General Health Questionnaire shows good psychometric coherency as evidenced by high internal consistency and unidimensionality of all but one of its constituent scales, and uniformly high loadings of all scales on a single overarching factor. These results are consistent with prior findings from the General Health Questionnaire developmental study and Brazilian adaptation studies.