Factor structure and internal consistency of the Self-Reporting Questionnaire (SRQ-20) in an urban population

This study focused on the psychometric properties of the Self-Reporting Questionnaire (SRQ-20) among workers, evaluating internal consistency criteria for the components scales and construct validity. Evaluation of the SRQ-20 performance used data from a cross-sectional study of a representative sample of workers from Feira de Santana, Bahia State, Brazil. The construct validity was estimated by means of an exploratory factor analysis of tetrachoric correlations and multiple correspondence analysis. The Kuder-Richardson formula (KD-20) was used to evaluate the instrument's internal consistency. Factor analysis of tetrachoric correlations revealed the extraction of four factors. Cumulative explanation of variance was 59.6%. Multiple correspondence analysis identified categories according to the groupings of variables comprising the questionnaire. Overall and standardized internal consistency coefficient was 0.80. The study indicated an acceptable performance by the SRQ-20 for evaluating common mental disorders, for use in mental health screening in the workplace.