A Confirmatory factor analysis of the General Health Questionnaire -12

Abstract

The General Health Questionnaire-12 is a widely used screening instrument for detecting psychological strain in the general population. A literature search of the PsycInfo database extracted 167 studies that used the GHQ-12 since 1990. The literature investigating the factor structure of the GHQ-12 has relied primarily on conventional factor analysis methods, the results of which are inconclusive. There is evidence in the literature supporting unidimensional, two-factor and three-factor conceptualizations of the GHQ-12. In the present paper we assess the adequacy of the factor structure of the GHQ-12 for one-factor, two-factor and three-factor solutions, using structural equations modelling and a longitudinal dataset drawn from 23 large New Zealand organizations. The results favour a two-factor model consisting of a Social Dysfunction factor and an Anxiety/Depression factor measured by four items each. Concurrent validity of the two factors was assessed separately through correlations with five criterion variables, and all correlations were in the expected direction. Theoretical implications for research using the GHQ-12 are discussed.