Making it Short: Shortening the Comprehensive Inventory of Mindfulness Experiences Using Ant Colony Optimization

Objectives The Comprehensive Inventory of Mindfulness Experiences (CHIME) comprises 37 items over eight domains and was validated in German and English languages using Rasch methodology. However, the length of the scale might limit its application due to the response burden it places on participants, especially in studies that examine additional constructs. This study aimed to develop a short but comprehensive CHIME version using cutting-edge methodology. Method Ant colony optimization was applied to optimize and reduce item content of individual CHIME facets and create 24-item (CHIME-S) and 16-item (CHIME-XS) versions. We used data collected in New Zealand ( n = 512), and in the USA, which included two independent samples ( n = 605 and n = 210). The construct validity of the newly developed CHIME-S and CHIME-XS was established by correlating its scores with measures of mindfulness, affect, and distress. Results Overall, the ant-colony algorithm identified a stable solution which included 3 best fitting items per facet CHIME short form (CHIME-S) and the 2 best-fitting items CHIME-XS (16 items). This solution was successfully replicated across all samples and the scale demonstrated acceptable confirmatory factor analysis fit and good internal consistency, and correlated with measures of mindfulness, distress, and affect in expected directions. Conclusions The CHIME-S and CHIME-XS are reliable and valid short-scale versions that can be used for assessment of total mindfulness and its facets in a comprehensive way. Future research efforts are invited to validate the CHIME-S and CHIME-XS across different cultures and sample populations, aiming at establishing robustness of the measure.