A Reliability Generalization Meta-analysis of the Padua Inventory-Revised (PI-R)

Background/Objective: The Padua Inventory-Revised (PI-R) is a widely applied instrument to measure obsessive-compulsive symptoms in clinical and nonclinical samples. We conducted a reliability generalization meta-analysis on the PI-R. Method: An exhaustive literature search yielded 118 empirical studies that had applied the PI-R, from which 30 studies (33 samples) reported an original reliability estimate. Results: Assuming a random-effects model, the average internal consistency reliability (Cronbach's alpha) was .92 (95% CI [.91, .93]) for the total scores, and ranged from .74 to .89 for the subscales. Assuming mixed-effects models, moderator analyses showed a positive statistically significant association between the standard deviation of the total scores and the reliability coefficients (p = .002; R(2) = .38). Conclusions: In terms of reliability, the PI-R scale was found to be adequate for both research and clinical purposes, although exhibiting large heterogeneity across studies. Future empirical studies using the PI-R should be required to provide at least one reliability estimate based on their own data.