title: A study of the psychometric properties of 12-item World Health Organization Disability Assessment Schedule 2.0 in a large population of people with chronic musculoskeletal pain.
abstract: OBJECTIVE
  To assess the validity of the Finnish translation of the 12-item World Health Organization Disability Assessment Schedule (WHODAS 2.0).
  
  
  METHODS
  Cross-sectional cohort survey study.
  
  
  METHODS
  Physical and Rehabilitation Medicine outpatient university clinic.
  
  
  METHODS
  The 501 consecutive patients with chronic musculoskeletal pain.
  
  
  METHODS
  Exploratory factor analysis and a graded response model using item response theory analysis were used to assess the constructs and discrimination ability of WHODAS 2.0.
  
  
  RESULTS
  The exploratory factor analysis revealed two retained factors with eigenvalues 5.15 and 1.04. Discrimination ability of all items was high or perfect, varying from 1.2 to 2.5. The difficulty levels of seven out of 12 items were shifted towards the elevated disability level. As a result, the entire test characteristic curve showed a shift towards higher levels of disability, placing it at the point of disability level of +1 (where 0 indicates the average level of disability within the sample).
  
  
  CONCLUSIONS
  The present data indicate that the Finnish translation of the 12-item WHODAS 2.0 is a valid instrument for measuring restrictions of activity and participation among patients with chronic musculoskeletal pain.
authors: 1 Department of Physical and Rehabilitation Medicine, Turku University Hospital and University of Turku, Turku, Finland.
authors: Mikhail
authors: M
authors: Saltychev
authors: 2 Turku University of Applied Sciences, Turku, Finland.
authors: Esa
authors: E
authors: Bärlund
authors: 3 Department of Orthopedic Surgery, Stanford University Health Care, Standford, CA, USA.
authors: Ryan
authors: R
authors: Mattie
authors: 4 Department of Physical Medicine and Rehabilitation, The Rehabilitation Institute of Chicago/Northwestern McGaw Medical Center, Chicago, IL, USA.
authors: Zachary
authors: Z
authors: McCormick
authors: 5 School of Health and Social Studies, JAMK University of Applied Sciences, Jyväskylä, Finland.
authors: Jaana
authors: J
authors: Paltamaa
authors: 1 Department of Physical and Rehabilitation Medicine, Turku University Hospital and University of Turku, Turku, Finland.
authors: Katri
authors: K
authors: Laimi
mesh_terms: D000328:Adult; D000368:Aged; D059350:Chronic Pain / Q000175:diagnosis* / Q000523:psychology; D015331:Cohort Studies; D003430:Cross-Sectional Studies; D004185:Disability Evaluation; D005260:Female; D005387:Finland; D006801:Humans; D008297:Male; D008875:Middle Aged; D059352:Musculoskeletal Pain / Q000175:diagnosis* / Q000523:psychology; D011594:Psychometrics; D011788:Quality of Life; D015203:Reproducibility of Results; D014177:Translations; D014421:Turkey; D014944:World Health Organization
keywords: Functioning; item response theory; pain assessment; participation (WHO ICF); psychometry