Longitudinal Measurement Properties of the Participation Questionnaire for Preschoolers: Reliability, Responsiveness, and Interpretability

Purpose This study aimed to evaluate the test−retest reliability, responsiveness, and interpretability of the Preschool Questionnaire for Participation (PQP), a tool for assessing participation in preschool children with autism spectrum disorder (ASD). Methods A cohort study was conducted with data collected at four time points over six months from children with ASD aged 51–75 months. Test−retest reliability was examined using intraclass correlation coefficients (ICCs) for 275 participants who completed the study. Responsiveness was examined by analyzing correlations between changes in PQP scores and changes in multiple scales based on four predefined hypotheses. To assess interpretability, the Global Rating of Change (GRC) Scale was used as an anchor to analyze receiver operating characteristic curves and estimate the minimal important change (MIC). Results ICCs ranged from 0.80 to 0.92 for individual factors and reached 0.93 for the total score. Three of the four hypotheses for responsiveness were supported within the expected range. However, the correlation between the GRC Scale and changes in PQP scores was below 0.3, preventing MIC calculation. Conclusion While the MIC could not be calculated, the PQP demonstrated test−retest reliability equivalent to or better than existing participation measures. Given the limited verification of responsiveness for other tools, the PQP’s strong longitudinal reliability and validity provide a foundation for future research.