Inter-rater reliability and smallest real difference of the Chinese Psychoeducational Profile-third edition for children with Autism Spectrum Disorder

The purpose of this study was to examine the inter-rater reliability of the Chinese version of the Psychoeducational Profile-third edition (CPEP-3) in children with Autism Spectrum Disorder. We also calculated the smallest real difference (SRD) for users to determine whether the change score rated by different raters for an individual child is valid. The CPEP-3 was administered to 42 children aged from 2 years 4 months to 7 years 7 months by two independent therapists twice, with an 11- to 21-day interval. The high internal consistency for performance subtests (Cronbach's alpha = 0.92–0.98) and composites (Cronbach's alpha = 0.92–0.95) in the CPEP-3 indicates the homogeneity of all the items in each subtest and composite. The inter-rater reliability of the CPEP-3, examined by intra-class correlation coefficient, ranged from 0.57 to 0.94 for the performance subtests, and 0.63 to 0.89 for the composites. The SRDs of the CPEP-3 ranged from 5.8 to 12.8 for the performance subtests, and 7.3 to 18.0 for the composites. The SRDs of the CPEP-3 were 14.4–51.8% of the possible highest scores of each subtest and composite. The substantial SRDs indicate that clinicians should consider such SRD values in determining whether a child's change score of the CPEP-3 indicates real change when the CPEP-3 is administered by different raters. Further studies to examine the construct validity, responsiveness, and minimally important difference of the CPEP-3 are needed to improve the utility of the CPEP-3.