Understanding the Dimensions of Post-Event Processing: Applying a Bifactor Modeling Approach to the EPEPQ-15.

Social anxiety disorder is maintained in part by rumination about past social experiences, known as post-event processing. The Extended Post-Event Processing Questionnaire (EPEPQ-15) assesses post-event processing as three correlated factors. Competing against this structure is a bifactor model that has not yet been evaluated for the EPEPQ-15. These models were tested for the conventional state version of the EPEPQ-15 and a new trait version in two separate samples (Ns = 327 and 351). In both samples, the fit of the bifactor model was better than that of correlated factor models. Moreover, the results did not support the group factors, indicating that a unidimensional interpretation of the EPEPQ-15 is most appropriate. The general dimension of the EPEPQ-15 was highly correlated with social interaction anxiety, beliefs related to social anxiety, anticipatory processing, and safety behaviors. These results overall suggest post-event processing is best conceptualized as a unitary construct.