An Examination of the Factor Structure of the Multidimensional Psychological Flexibility Inventory.

The Multidimensional Psychological Flexibility Inventory (MPFI), a 60-item self-report measure, assesses the Acceptance and Commitment Therapy Hexaflex. The factor structure of the MPFI was examined in this study. In a community sample of adults (N = 827), four models (correlated six-factor, one-factor, higher order, and bifactor) were tested for each of the constructs of interest (i.e., psychological flexibility and psychological inflexibility). All models, with the exception of the one-factor, provided adequate fit to the data. Differences between the three adequate fitting models were trivial in magnitude. Additional statistical indices from the bifactor models indicated that the general factors accounted for the large majority of reliable variance. The majority of the domain-specific factors evidenced redundancy with their respective general factors. Results from a series of structural regressions indicated that the domain-specific factors did not provide additional incremental utility above and beyond the general factors in predicting two relevant clinical constructs (i.e., health anxiety and depression). These results provide support for the use of the MPFI Flexibility and Inflexibility total scores, but not subscale scores. The MPFI may require further refinement to either greatly reduce the length of the measure, or to ensure that subscales have incremental utility.