Psychometric properties of the general anxiety disorders-7 scale using categorical data methods : a study in a sample of university attending Ethiopian young adults

Abstract

Background: Few studies have investigated the psychometric validation of the General Anxiety Disorders-7 Scale (GAD-7) using appropriate data assumptions. This study examined the reliability, factorial validity, divergent validity, and item analysis of the GAD-7 using categorical data methods in a sample of Ethiopian young adults. Methods: A sample of 270 students in the age group (18–20 years) was recruited during February-May of 2017 in this cross-sectional study using simple random sampling. The participants completed a tool for socio-demographic details, the GAD-7, and the Perceived Stress Scale-10 (PSS-10). Results: The cumulative variance rule (> 40%), the scree test, Kaiser’s criteria (Eigenvalues > 1), and the parallel analysis found a 1-factor model for the GAD-7 (factor loadings, 0.38 to 0.63). Fit indices suggested a 1-factor model: the tests applied included the weighted root mean square residual (0.030), comparative fit index (1.000), the goodness of fit index (1.00), root mean square error of approximation (0.037) and the non-normed fit index (1.00). McDonald’s Omega (0.772) implied that the scores had adequate internal consistency. Divergent validity was supported by significant but weak correlations that were found between the GAD-7 and PSS-10 scores (r = 0.11 to 0.25, p<0.05). Conclusion: The psychometric validity of the GAD-7 in Ethiopian university attending young adults was supported by the categorical data method.