Assessing mechanisms of mindfulness: Improving the precision of the Nonattachment Scale using a Rasch model

Abstract

Nonattachment, or the lack of possessive and mental fixations and clinging, is considered a key element by which mindfulness cultivates psychological wellbeing. The 30-item Nonattachment Scale (NAS) is a measure of nonattachment, but its item functioning and measurement precision remain to be explored. The present study used a Rasch model to examine 434 participants’ responses to the NAS. Disordered thresholds were corrected by uniform item re-scoring. Satisfactory model fit was achieved after removing four misfitting items and combining locally dependent items into sub-tests. NAS item functioning improved significantly following these minor modifications. In addition, by combining particular response options upon scoring, researchers can utilize our modified version without the need to alter current response formatting, thus offering them greater precision in their measurement of nonattachment. Ordinal-to-interval conversion tables presented in the manuscript further increases precision of our proposed 26-item version of the instrument and enables use of the scale without the need to violate fundamental assumptions of parametric statistics.