Internal consistency of the self-reporting questionnaire-20 in occupational groups

Abstract

OBJECTIVE: To assess the internal consistency of the measurements of the Self-ReportingQuestionnaire (SRQ-20) in different occupational groups.METHODS: A validation study was conducted with data from four surveys with groups ofworkers, using similar methods. A total of 9,959 workers were studied. In all surveys, the commonmental disorders were assessed via SRQ-20. The internal consistency considered the itemsbelonging to dimensions extracted by tetrachoric factor analysis for each study. Item homogeneityassessment compared estimates of Cronbach’s alpha (KD-20), the alpha applied to a tetrachoriccorrelation matrix and stratified Cronbach’s alpha.RESULTS: The SRQ-20 dimensions showed adequate values, considering the referenceparameters. The internal consistency of the instrument items, assessed by stratified Cronbach’salpha, was high (> 0.80) in the four studies.CONCLUSIONS: The SRQ-20 showed good internal consistency in the professional categoriesevaluated. However, there is still a need for studies using alternative methods and additionalinformation able to refine the accuracy of latent variable measurement instruments, as in thecase of common mental disorders