Validation of the Personalized Psychological Flexibility Index in a Portuguese sample
DOI:
https://doi.org/10.31211/rpics.2025.11.1.398Keywords:
Psychometric study, Psychological Flexibility, PPFI, Validation, Confirmatory Factor AnalysisAbstract
Background: Psychological flexibility is essential for mental health, yet its assessment still lacks instruments suited to the Portuguese context. This study aimed to address that gap by validating an innovative instrument that integrates specific dimensions and presents robust evidence of reliability and validity, distinguishing it from existing measures. Aim: To validate the Personalized Psychological Flexibility Index (PPFI) for the Portuguese population by analyzing its factorial structure, internal consistency, item quality, test-retest reliability, and relationship with relevant variables. Method: A total of 368 participants aged between 18 and 62 (M = 25.44, SD = 9.50) completed an online protocol comprising sociodemographic questions and self-report instruments assessing psychological flexibility (PPFI and MPFI-24), values (ELS-9), psychological inflexibility (AAQ-II), and positive and negative affect (PANAS). The PPFI retest was conducted with 57 participants after a four-week interval. Results: Confirmatory factor analysis supported a hierarchical model with a higher-order factor (total score) and three lower-order factors (Avoidance, Acceptance, and Engagement), yielding acceptable fit indices. The PPFI demonstrated good reliability (α = 0.70) for both the total score and subfactors and strong test-retest reliability. It positively correlated with psychological flexibility (MPFI-24), personal values (ELS-9), and positive affect (PANAS-P) and negatively with experiential avoidance (AAQ-II) and negative affect (PANAS-N). Age and gender showed no significant correlation with the overall PPFI score. Conclusions: The PPFI proved to be a valid and reliable instrument for assessing psychological flexibility in Portuguese adults. Its validation contributes to evidence-based practice and is particularly relevant for research on the effectiveness of interventions promoting psychological flexibility.
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