Aim: Children and adolescents highly value their ability to participate in relevant daily life and recreational activities. The Activities Scale for Kids-performance (ASKp) instrument measures the frequency of performance of 30 common childhood activities, and has been shown to be valid and reliable. A revised and expanded 38-item ASKp (ASKp38) version has been reported in recent literature and is currently used in clinical research. The aim of this paper is to assess the factor structure and item-level statistics of the ASKp38. Method: Our study used factor analyses and Rasch analyses to determine the item-set dimensionality and to calculate item-level statistics respectively, for existing ASKp38 data from 200 children (104 males; 96 females; mean age 12y 7mo; SD 2y 8mo; range 6-20y) with physical disabilities. The children had a variety of physical impairments including cerebral palsy (n=105; range 8-13y), limb salvage (n=18; range 11-20y), arthrogryposis (n=13; 6-17y), and other, including individuals with spina bifida and spinal cord injury (n=64; 8-19y). Results: A two-factor model, with components of activities of daily living and play, most optimally fit the data. Item-fit statistics based on this two-factor model demonstrated adequate fit and content coverage. Interpretation: The ASKp38 appears to consist of two factors, defined as (1) activities of daily living and (2) play, and may be used to measure the frequency of activity performance on two corresponding subscales.