Validity Evidence of an Instrument for Mindfulness Assessment (MA) Based on its Internal Structure and External Criterion

Abstract Operationalizing the concept of mindfulness has been a challenge for researches. In this article, we present and discuss the procedures for the assessment of the internal structure and validity of the criteria for Mindfulness Assessment (MAP), as well as the results obtained. The collection of factors was done by exploratory factor analysis (EFA), and item- selection by item response theory (IRT). This study counted with 788 Brazilians, with ages ranging from 17 to 65 years (M = 26.11; SD = 9.59); 79% of which were women. Four factors were extracted: Mindfulness (α = 0.88), Attention (α = 0.84), Acceptance (α = 0.74) and Novelty seeking (α = 0.62). 47 items were retained in the MAP. We also compared the scores between non-meditator (n = 653) and meditator (n = 112) respondents. Analyses by IRT showed the items to be adequately adjusted. Significant differences between scores of meditators and non-meditator respondents were revealed. These findings suggest that the MAP is a valid and reliable instrument, regarding its internal structure and criterion-related evidence, which suggests its appropriateness in the study of adults.