Measuring mindfulness at interval level: Transformation of the Five Facet Mindfulness Questionnaire using Rasch approach

Abstract

Introduction: Significant contribution of mindfulness to individuals’ health and well-being requires precise mindfulness measures for accurate assessment of psychological and cognitive changes in individuals undergoing mindfulness-based interventions. The widely used measure of trait mindfulness the 39-item Five Facet Mindfulness Questionnaire (FFMQ; Baer, Smith, Hopkins, Krietemeyer, & Toney, 2006) including: Observing, Describing, Act With Awareness, Non-Judging and Non-reacting to inner experience has shown acceptable psychometric properties but no efforts were made to increase precision of its subscales in discriminating between trait levels. Method: Rasch analysis was conducted to enhance the psychometric properties of the FFMQ using sample of 296 participants. Results: The best fit to the Rasch model was achieved for all five FFMQ subscales after minor modifications that involved combining locally dependent items into subtests and removing two items that critically affected the estimates. Discussion: Findings support structural validity of the FFMQ subscales and allow researchers and clinicians transform ordinal FFMQ responses to interval level data suitable for parametric statistics, which increases measurement precision. Conversion tables are included here for convenience and can be used without any modifications of the original FFMQ response format. Further implications of these findings are discussed.