Center for Research in Neuropsychology and Cognitive Behavioral Intervention

The MPFI-24 is an inventory composed of 24 items designed to measure psychological flexibility and inflexibility. The 24 items are assessed on a six-point scale ranging from never true (1) to always true (6). This abbreviated version assesses psychological flexibility (first 12 items) and psychological inflexibility (last 12 items). Each of these composite indices (PF and PI) encompasses six factors corresponding to the Hexaflex model of ACT.

Confirmatory factor analysis tested four models (six correlated factors, one factor, higher-order, and bifactor) for each of the global indices of Psychological Flexibility (PF) and Psychological Inflexibility (PI). The six correlated factors model and the bifactor model demonstrated the best fit. The MPFI24-A demonstrated good reliability for both overall scores (α = .90 and α = .85, respectively) and good test-retest reliability. It showed expected associations with other constructs of interest (psychological flexibility, symptoms of anxiety and depression, and perception of mental health).