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Research Article  |   January 1999
The Use of Rasch Analysis To Produce Scale-Free Measurement of Functional Ability
Author Affiliations
  • Craig A. Velozo, PhD, OTR, is Associate Professor, Department of Occupational Therapy, University of Illinois at Chicago, M/C 811, 1919 West Taylor Street, Chicago, Illinois 60612
  • Gary Kielhofner, DrPH, OTR, FAOTA, is Professor and Head, Department of Occupational Therapy, University of Illinois at Chicago, Chicago, Illinois
  • Jin-Shei Lai, PhD, OTR, is Research Assistant Professor, Department of Occupational Therapy, University of Illinois at Chicago, Chicago, Illinois
Article Information
Assessment Development and Testing / Special Issue on Faculty Development, Terrie Nolinske, Guest Editor / Quantitative Research Series
Research Article   |   January 1999
The Use of Rasch Analysis To Produce Scale-Free Measurement of Functional Ability
American Journal of Occupational Therapy, January/February 1999, Vol. 53, 83-90. doi:10.5014/ajot.53.1.83
American Journal of Occupational Therapy, January/February 1999, Vol. 53, 83-90. doi:10.5014/ajot.53.1.83
Abstract

Innovative applications of Rasch analysis can lead to solutions for traditional measurement problems and can produce new assessment applications in occupational therapy and health care practice. First, Rasch analysis is a mechanism that translates scores across similar functional ability assessments, thus enabling the comparison of functional ability outcomes measured by different instruments. This will allow for the meaningful tracking of functional ability outcomes across the continuum of care. Second, once the item–difficulty order of an instrument or item bank is established by Rasch analysis, computerized adaptive testing can be used to target items to the patient’s ability level, reducing assessment length by as much as one half. More importantly, Rasch analysis can provide the foundation for “equiprecise” measurement or the potential to have precise measurement across all levels of functional ability. The use of Rasch analysis to create scale-free measurement of functional ability demonstrates how this methodology can be used in practical applications of clinical and outcome assessment.