The Personalized Psychological Flexibility Index (PPFI): An Item Response Theory Analysis with Racially Diverse College Students

The present study investigated the psychometric properties of the Personalized Psychological Flexibility Index (PPFI) in a racially diverse sample of college students. Seven hundred twenty-three undergraduate students were recruited from a four-year public university in Hawaiʻi, USA. Confirmatory factor analyses were initially conducted to examine whether the theory-driven three-factor structure (i.e., Avoidance, Acceptance, and Harnessing) found in previous studies was identified in the current sample. The Generalized Partial Credit Model (GPCM), an item response theory (IRT) model for polytomous responses, was then used to explore the adequacy and accuracy of items and their response categories. We found a three-dimensional structure of PPFI, with minor modification for a correlated error term allowed between two items to be best fit of the present data. The GPCM analysis also indicated that, while most items in the Avoidance and Acceptance factors reliably measured the intended constructs, several items in the Harnessing factor showed suboptimal item information. Furthermore, our findings suggested reducing the 7-point original response categories to 5-point ones given the probabilities endorsed by items. Using an IRT model, this was the first study that investigated the psychometric properties of PPFI with a racially diverse sample of college students. While the PPFI is a promising measure of psychological flexibility, we found the areas of improvement through examining it at the item level.