Assessing the psychometric properties of the comprehensive inventory of mindfulness experiences (CHIME) using rasch analysis

Mindfulness-based interventions are found beneficial to improving well-being and alleviating symptoms of psychological distress, although accurate measurement of the psychological construct of mindfulness remains a challenge. Theoretical work has highlighted characteristics of mindfulness, which can be assessed comprehensively by the recently developed eight-factor Comprehensive Inventory of Mindfulness Experiences (CHIME). While the instrument has demonstrated acceptable psychometric properties, its ability to discriminate precisely across individual mindfulness levels has not been rigorously investigated. The current study subjected responses of 443 participants to Rasch analysis to investigate and enhance the psychometric properties of the CHIME. The best fit to the Rasch model was achieved for every individual subscale with only minor modifications that involved combining some locally dependent items into a testlet. The total scale was then fitted to the Rasch model with individual subscales treated as testlets, and the best model fit was attained after two correlated subscales were treated as a single testlet, χ2(63) = 70.76, p = .23. Therefore, it was possible to generate ordinal-to-interval conversion tables for individual subscales and the total scale scores, which increase the instrument’s precision. The results support internal construct validity and enhance psychometric properties of the CHIME.