Incremental Validity of Cognitions in a Clinical Case Formulation: An Intraindividual Test in a Case Example

Abstract

Incremental validity, the ability of a measure to predict or explain variance over and above other measures, is an important psychometric characteristic of standardized measures, but has received little attention idiographically. Idiographic assessment may be an important part of developing a clinical case formulation, guiding treatment by developing an individualized understanding of the variables that trigger and maintain distress. This study examined whether the idiosyncratic cognitive schema hypothesized by a clinician in a cognitive case formulation explained distress incrementally over that of situational triggers. Using daily ratings of situational triggers, idiosyncratic cognitions, and distress, the incremental validity of cognitions in predicting each of six distress measures was tested in a case example using dynamic time series regression. The incremental variance explained by cognitions varied across the distress measures, suggesting that, in this case example, targeting thoughts and beliefs for treatment may be important for only certain types of distress.