Rasch analysis of the Frost Multidimensional Perfectionism Scale

Objective: The Frost Multidimensional Perfectionism Scale (FMPS) is widely used to measure the construct of perfectionism. Previous studies evaluating the factor structure of the FMPS have reported inconsistent findings. The study objective was to examine the psychometric properties of proposed four, five, and six factor solutions of the FMPS using Rasch analysis. Method: Using the responses from a sample of New Zealand athletes and exercisers (n = 425) from a variety of sports, we subjected the dataset to Rasch analysis. The overall and individual item fit, unidimensionality, local independence, and person separation reliability were evaluated by treating factors of each model as subtests. Results: After disordered thresholds were uniformly rescored, the factor Organisation displayed significant misfit to the model across all three solutions tested. Removal of Organisation and combining two parental facets into one resulted in adequate model fit and good item discrimination ability for all three solutions. The modified six-factor model was the best in terms of reliability, with no differential item functioning and the highest person separation index. Conclusion: The present results support the psychometric properties and internal structural validity of the rescored FMPS with the parental factors combined and without the Organisation facet. Psychometric properties of the instrument can be further enhanced by using the ordinal-to-interval conversion table presented here, which does not require modification of the original response format. These findings will be of interest in different areas where accurate assessment of the overall perfectionism trait is important and open new avenues for perfectionism research.