Interpretational issues with the bifactor model: A commentary on 'Defining the p-Factor: An Empirical Test of Five Leading Theories' by Southward, Cheavens, and Coccaro

Southward, Cheavens, and Coccaro (2022, Psychological Medicine) conducted an ambitious investigation aimed at determining the nature of the general p factor of psychopathology by considering the correlation between the p factor and five candidate constructs. Generally, in this area of research, the bifactor model is preferred to the second order common factor model. In this commentary, we identify several interpretational issues concerning the bifactor model, which are based on a realistic psychometric view of latent variables. These issues may hamper the study of the nature of p factor model using the bifactor model.