Specific Objectivity of Mindfulness—A Rasch Analysis of the Freiburg Mindfulness Inventory

Even as modern research on mindfulness has expanded, debate continues with regard to the measurement and conceptualization
of mindfulness. This divergence has manifested in a proliferation of different measurement approaches. The present research
contributes to the advancement of mindfulness measurement by performing a Rasch model analysis of the psychometric properties
of the short form of the Freiburg Mindfulness Inventory (FMI-14). This rigorous psychometric method belongs to the family
item response theory and can be considered to be a set of approaches complementing classical test theory. The FMI-14 was administered
to a nonclinical convenience sample of N = 1,452 German adults. Our data showed poor fit to the Rasch model. A reanalysis of the model excluding one particular misfitting
item (number 13) yielded an acceptable fit for the originally proposed one-factorial solution to the Rasch model. However,
a two-factorial solution with the subfacets “presence” and “acceptance” provided a better overall fit than the unidimensional
solution. Some degree of differential item functioning could be observed both in the uni- and two-dimensional solution suggesting
that potential exists for improving the measurement quality of the FMI-13. In line with the recent research, it is concluded
that the FMI-13 should be considered as a two-dimensional rather than a unidimensional instrument.