title: A systematic literature review on the application of Rasch analysis in musculoskeletal disease -- a special interest group report of OMERACT 11.
abstract: OBJECTIVE
  The Rasch measurement model provides robust analysis of the internal construct validity of outcome measures. We reviewed the application of Rasch analysis in musculoskeletal medicine as part of the work leading to discussion in a Special Interest Group in Rasch Analysis at Outcome Measures in Rheumatology 11.
  
  
  METHODS
  A systematic literature review of SCOPUS and MEDLINE was performed (January 1, 1985, to February 29, 2012. Original research reports in English using "Rasch" or "Item Response Theory" in musculoskeletal diseases were assessed by 2 independent reviewers. The topics of focus and analysis methodology details were recorded.
  
  
  RESULTS
  Of 212 articles reviewed, 114 were included. The number of publications rose from 1 in 1991-1992 to 23 in 2011-February 2012. Disease areas included rheumatoid arthritis (28%), osteoarthritis (16.6%), and general musculoskeletal disorders (43%). Sixty-six reports (57.9%) evaluated psychometric properties of existing scales and 35 (30.7%) involved development of new scales. Nine articles (7.9%) were on methodology illustration. Four articles were on item banking and computer adaptive testing. A majority of the articles reported fit statistics, while the basic Rasch model assumption (i.e., unidimensionality) was examined in only 57.2% of the articles. An improvement in reporting qualities with Rasch articles was noted over time. In addition, only 11.4% of the articles provided a transformation table for interval scale measurement in clinical practice.
  
  
  CONCLUSIONS
  The Rasch model has been increasingly used in rheumatology over the last 2 decades in a wide range of applications. The majority of the articles demonstrated reasonable quality of reporting. Improvements in quality of reporting over time were revealed.
authors.affiliation: From the Department of Rheumatology and Immunology, Singapore General Hospital, the Duke-National University of Singapore Graduate Medical School, Singapore; Division of Musculoskeletal and Rehabilitation Medicine, University of Leeds, Leeds, UK; and the National Institute for Health Research (NIHR) Leeds Musculoskeletal Biomedical Research Unit, Leeds, UK.
authors.forename: Ying-Ying
authors.initials: YY
authors.lastname: Leung
authors.forename: May-Ee
authors.initials: ME
authors.lastname: Png
authors.forename: Philip
authors.initials: P
authors.lastname: Conaghan
authors.forename: Alan
authors.initials: A
authors.lastname: Tennant
mesh_terms: D006801:Humans; D009140:Musculoskeletal Diseases; D017063:Outcome Assessment, Health Care / Q000379:methods*; D011594:Psychometrics / Q000379:methods; D012219:Rheumatology / Q000379:methods*; D011795:Surveys and Questionnaires
keywords: ITEM RESPONSE THEORY; MUSCULOSKELETAL DISORDERS; RASCH ANALYSIS; RHEUMATOLOGY