Construct Validity of the Activities Scale for Kids Performance in Children with Cerebral Palsy: Brief Report.

: This study collects evidence of construct convergent validity of the Activity Scale for Kids performance (ASKp), comparing its results with the 66-item Gross Motor Function Measure (GMFM-66) and with the Gross Motor Function Classification System (GMFCS) and testing the ASKp's ability to discriminate between individuals with different functional capabilities. : This cross-sectional study involved 60 children with spastic cerebral palsy (CP) assessed with the GMFM-66 who self-administered the Italian version of the ASKp. : Children were 10.9 (±3) years old with GMFCS Level I-III. Moderate correlations were found between GMFM and ASKp scores (r = 0.577; < .001), and between GMFCS levels and ASKp score (r = -0.541, < .001). The ASKp discriminated between children with different functional capabilities, determined by the GMFCS (F = 18.2, < .001). : ASKp is valid to assess physical functioning, a crucial domain in rehabilitation of children with spastic CP. : ClinicalTrials.gov Identifier: NCT03325842.