Objective: To develop and investigate the psychometric property of the short Thai version of the Philadelphia Mindfulness Scale (PHLMS).
Methods: The pooled data from the mindfulness invention studies between 2011 and 2014 were analyzed. The items of original version were selected by 3 methods i.e., mean difference between the two groups of high score and low score by t35-test, researchers’ opinion and corrected item total correlation. Two forms of short Thai version were developed. These forms were analyzed by using exploratory factor analysis (EFA) in randomly selected 303 cases and only the selected form was confirmed by confirmatory factor analysis (CFA) in 873 cases by using the Mplus program. The goodness of fit indices was determined by Chi-square index, root mean square error of approximation (RMSEA), comparative fit index (CFI) and Tucker-Lewis Index (TLI). Pearson’s correlation was used to analyze the discriminant validity with Hospital Anxiety Depression Scale (HAD).
Results: Only the researchers’ opinion version (ROV) containing 10 items was confirmed by CFA and had factor loadings between 0.50-0.80. The goodness of fit was acceptable. The ROV and each domain (awareness and acceptance) had acceptable composite reliability at 0.86, 0.72 and 0.83 respectively.
Conclusion: The short version of PHLMS contained 10 items and demonstrated the good validity among clinical cases, beginners in meditation practice and care givers; and could classify people with different frequencies of meditation practice
