Psychological inflexibility is a rigid behavioral pattern that interferes with engagement in personally meaningful activities; it is the hypothesized root of suffering in acceptance and commitment therapy (ACT). Thus, the quality of its measurement affects the research, theory, and practice of ACT. The current study aimed to evaluate the discriminant validity and item performance of four measures of psychological inflexibility: the Acceptance and Action Questionnaire—II (AAQ-II), a revised version of the AAQ-II (AAQ-3), the Brief Experiential Avoidance Questionnaire (BEAQ), and the Comprehensive assessment of Acceptance and Commitment Therapy processes (CompACT). We analyzed data from community (n = 253), student (n = 261), and treatment-seeking samples (n = 140) using exploratory factor analysis and multigroup graded-response models. The CompACT had the strongest discriminant validity followed by the AAQ-3, whereas items in the CompACT Behavioral Awareness and Valued Action subscales performed most consistently across groups. No single measure emerged as clearly superior to others; rather, appropriate selection of measures depends on the goals and context of assessment. Scientific and clinical implications are discussed.

心理上的僵硬是一种僵化的行为模式，会干扰个人有意义的活动。它是接受和承诺治疗（ACT）的假想根源。因此，其测量的质量会影响ACT的研究，理论和实践。当前的研究旨在评估四种心理僵化措施的判别效度和项目表现：接受和行动问卷-II（AAQ-II），AAQ-II（AAQ-3）的修订版，短暂的经验回避问卷（BEAQ），以及对接受和承诺治疗过程的综合评估（CompACT）。我们分析了来自社区（n  = 253），学生（n  = 261）和寻求治疗的样本（n = 140），使用探索性因素分析和多组分级响应模型。CompACT具有最高的判别效度，紧随其后的是AAQ-3，而CompACT行为意识和有价值行动分量表中的项目在各组中表现最为一致。没有任何一项措施明显优于其他措施。相反，措施适当的选择取决于目标和评估的情况下。讨论了科学和临床意义。