Measurement properties of the Activities Scale for Kids

Young, Nancy L.; Williams, J.Ivan; Yoshida, Karen K.; Wright, James G.

« Previous Next »Journal of Clinical Epidemiology
Volume 53, Issue 2 , Pages 125-137, February 2000

Measurement properties of the Activities Scale for Kids

Nancy L. Young
- Division of Pediatric Medicine, The Hospital for Sick Children, Toronto, Ontario, Canada,
- Department of Pediatrics, University of Toronto, Toronto, Ontario, Canada,
- Graduate Department of Rehabilitation Science, University of Toronto, Toronto, Ontario, Canada,
- Corresponding author. Tel.: (416) 813-5446; fax: (416) 813-5663. E-mail address:(N.L. Young)
J.Ivan Williams
- Institute for Clinical Evaluative Sciences, North York, Ontario, Canada,
- Institute of Medical Sciences, University of Toronto, Toronto, Ontario, Canada,
Karen K. Yoshida
- Graduate Department of Rehabilitation Science, University of Toronto, Toronto, Ontario, Canada,
- Department of Physical Therapy, University of Toronto, Toronto, Ontario, Canada,
James G. Wright
- Division of Orthopedic Surgery, The Hospital for Sick Children, Toronto, Ontario, Canada,
- Departments of Surgery and Public Health Sciences, University of Toronto, Toronto, Ontario, Canada

Received 1 June 1998; received in revised form 14 May 1999; accepted 17 May 1999.

Abstract

The Activities Scale for Kids (ASK) is a self-report measure of childhood physical disability, that has excellent reliability (ICC=0.97). The purpose of this study was to assess further the ASK's measurement properties. ASK questionnaires were completed by 200 children with musculoskeletal limitations (mean age, 10.1 years). Rasch analyses confirmed that all items measured the same construct and supported aggregation of a summary score. Validity of the ASK was demonstrated by a correlation of 0.81 (P < 0.0001) with parent-reported Childhood Health Assessment Questionnaire scores; a significant difference in scores according to clinicians' global ratings of disability (P < 0.0001), and a correlation of 0.92 (P < 0.0001) with clinician-observation. The ASK showed minimal ceiling effects, no floor effects, and changed by 1.73 standard deviation units after clinically important change. The ASK is a valid and responsive outcome measure that permits 5- to 15-year-old childrens' physical functioning in the community to be assessed accurately by mail. The quality of this measure will enable clinical studies to measure outcome not only in a way that is relevant to patients, but also in a way that is sensitive to small amounts of change and is practical and inexpensive.

Keywords: Measurement, Disability, Activities of daily living, Pediatrics, Psychometric properties, Self-report