Chinese translation and validation of the Personalized Psychological Flexibility Index (PPFI) for medical college students

Abstract Background Psychological flexibility (PF) is defined as the ability to pursue valuable life goals despite the existence of distress. The Personalized Psychological Flexibility Index (PPFI) is a new measure of psychological flexibility that can address existing deficiencies. This study aimed to translate and validate the psychometric characteristics of the Chinese version of the PPFI among medical college students. Methods The study was conducted in two phases. Phase 1 involved the translation and cross-cultural adaptation of the PPFI according to guidelines recommended by the International Society for Pharmacoeconomics and Outcomes Research (ISPOR). Phase 2 was a cross-sectional survey conducted on 945 medical college students in China. The psychometric performances of the scale were assessed using construct validity, divergent validity, criterion validity, incremental validity, internal consistency, and test-rest reliability. Results The exploratory factor analysis (EFA, n1 = 440) showed that the Chinese version of the PPFI consisted of 3 factors, with a total of 15 items. The confirmatory factor analysis (CFA, n2 = 440) showed that the three-factor structure fit well (χ2/ $$df$$ df =2.469, SRMR = 0.051, RMSEA = 0.058, GFI = 0.94, CFI = 0.985). The total Chinese PPFI score had a moderate positive association with the Comprehensive Assessment of Acceptance and Commitment Therapy (CompACT, r = 0.344) and a negative association with the Acceptance and Action Questionnaire-II (AAQ-II, r = -0.334). Furthermore, the Chinese PPFI demonstrated good internal consistency (Cronbach's α = 0.826) and test–retest reliability (ICC = 0.817, p