title: Measurement precision and efficiency of multidimensional computer adaptive testing of physical functioning using the pediatric evaluation of disability inventory.
abstract: OBJECTIVE
  To compare the measurement efficiency and precision of a multidimensional computer adaptive testing (M-CAT) application to a unidimensional CAT (U-CAT) comparison using item bank data from 2 of the functional skills scales of the Pediatric Evaluation of Disability Inventory (PEDI).
  
  
  METHODS
  Using existing PEDI mobility and self-care item banks, we compared the stability of item calibrations and model fit between unidimensional and multidimensional Rasch models and compared the efficiency and precision of the U-CAT- and M-CAT-simulated assessments to a random draw of items.
  
  
  METHODS
  Pediatric rehabilitation hospital and clinics.
  
  
  METHODS
  Clinical and normative samples.
  
  
  METHODS
  Not applicable.
  
  
  METHODS
  Not applicable.
  
  
  RESULTS
  The M-CAT had greater levels of precision and efficiency than the separate mobility and self-care U-CAT versions when using a similar number of items for each PEDI subdomain. Equivalent estimation of mobility and self-care scores can be achieved with a 25% to 40% item reduction with the M-CAT compared with the U-CAT.
  
  
  CONCLUSIONS
  M-CAT applications appear to have both precision and efficiency advantages compared with separate U-CAT assessments when content subdomains have a high correlation. Practitioners may also realize interpretive advantages of reporting test score information for each subdomain when separate clinical inferences are desired.
authors.affiliation: Health and Disability Research Institute, Boston University, Boston, MA 02215, USA. smhaley@bu.edu
authors.forename: Stephen M
authors.initials: SM
authors.lastname: Haley
authors.forename: Pengsheng
authors.initials: P
authors.lastname: Ni
authors.forename: Larry H
authors.initials: LH
authors.lastname: Ludlow
authors.forename: Maria A
authors.initials: MA
authors.lastname: Fragala-Pinkham
mesh_terms: D000293:Adolescent; D002648:Child; D002675:Child, Preschool; D003201:Computers; D004185:Disability Evaluation; D006233:Persons with Disabilities / Q000145:classification* / Q000534:rehabilitation; D004526:Efficiency; D006801:Humans; D007223:Infant; D017063:Outcome Assessment, Health Care; D010372:Pediatrics; D011594:Psychometrics; D012648:Self Care