title: Integrating patient reported outcome measures and computerized adaptive test estimates on the same common metrics: an example from the assessment of activities in rheumatoid arthritis.
abstract: OBJECTIVE
  This study aimed to explore the potential of an inclusive and fully integrated measurement system for the Activities component of the International Classification of Functioning, Disability and Health (ICF), incorporating four classical scales, including the Health Assessment Questionnaire (HAQ), and a Computerized Adaptive Testing (CAT).
  
  
  METHODS
  Three hundred patients with rheumatoid arthritis (RA) answered relevant questions from four questionnaires. Rasch analysis was performed to create an item bank using this item pool. A further 100 RA patients were recruited for a CAT application. Both real and simulated CATs were applied and the agreement between these CAT-based scores and 'paper-pencil' scores was evaluated with intraclass correlation coefficient (ICC). Anchoring strategies were used to obtain a direct translation from the item bank common metric to the HAQ score.
  
  
  RESULTS
  Mean age of 300 patients was 52.3 ± 11.7 years; disease duration was 11.3 ± 8.0 years; 74.7% were women. After testing for the assumptions of Rasch analysis, a 28-item Activities item bank was created. The agreement between CAT-based scores and paper-pencil scores were high (ICC = 0.993). Using those HAQ items in the item bank as anchoring items, another Rasch analysis was performed with HAQ-8 scores as separate items together with anchoring items. Finally a conversion table of the item bank common metric to the HAQ scores was created.
  
  
  CONCLUSIONS
  A fully integrated and inclusive health assessment system, illustrating the Activities component of the ICF, was built to assess RA patients. Raw score to metric conversions and vice versa were available, giving access to the metric by a simple look-up table.
authors.affiliation: Department of Biostatistics, Faculty of Medicine, Ankara University, Ankara, Turkey.
authors.forename: Beyza
authors.initials: B
authors.lastname: Doğanay Erdoğan
authors.affiliation: Department of Biostatistics, Faculty of Medicine, Ankara University, Ankara, Turkey.
authors.forename: Atilla Halİl
authors.initials: AH
authors.lastname: Elhan
authors.affiliation: Department of Biostatistics, Faculty of Medicine, Ankara University, Ankara, Turkey.
authors.forename: Osman Tolga
authors.initials: OT
authors.lastname: Kaskatı
authors.affiliation: Department of Biostatistics, Faculty of Medicine, Ankara University, Ankara, Turkey.
authors.forename: Derya
authors.initials: D
authors.lastname: Öztuna
authors.affiliation: Department of Physical Medicine and Rehabilitation, Faculty of Medicine, Ankara University, Ankara, Turkey.
authors.forename: Ayşe Adile
authors.initials: AA
authors.lastname: Küçükdeveci
authors.affiliation: Department of Physical Medicine and Rehabilitation, Faculty of Medicine, Ankara University, Ankara, Turkey.
authors.forename: Şehim
authors.initials: Ş
authors.lastname: Kutlay
authors.affiliation: Swiss Paraplegic Research, Nottwil, Switzerland.
authors.forename: Alan
authors.initials: A
authors.lastname: Tennant
mesh_terms: D000203:Activities of Daily Living; D000328:Adult; D000368:Aged; D001172:Arthritis, Rheumatoid / Q000175:diagnosis* / Q000503:physiopathology; D001696:Biomechanical Phenomena; D017281:Cost of Illness; D003936:Diagnosis, Computer-Assisted; D004185:Disability Evaluation; D005260:Female; D006304:Health Status; D006801:Humans; D008297:Male; D008875:Middle Aged; D051346:Mobility Limitation; D000071066:Patient Reported Outcome Measures; D011237:Predictive Value of Tests; D015203:Reproducibility of Results; D012648:Self Care; D012919:Social Behavior
keywords: Rasch analysis; computerized adaptive testing; item bank; rheumatoid arthritis