title: Developing the World Health Organization Disability Assessment Schedule 2.0.
abstract: OBJECTIVE
  To describe the development of the World Health Organization Disability Assessment Schedule 2.0 (WHODAS 2.0) for measuring functioning and disability in accordance with the International Classification of Functioning, Disability and Health. WHODAS 2.0 is a standard metric for ensuring scientific comparability across different populations.
  
  
  METHODS
  A series of studies was carried out globally. Over 65,000 respondents drawn from the general population and from specific patient populations were interviewed by trained interviewers who applied the WHODAS 2.0 (with 36 items in its full version and 12 items in a shortened version).
  
  
  RESULTS
  The WHODAS 2.0 was found to have high internal consistency (Cronbach's alpha, α: 0.86), a stable factor structure; high test-retest reliability (intraclass correlation coefficient: 0.98); good concurrent validity in patient classification when compared with other recognized disability measurement instruments; conformity to Rasch scaling properties across populations, and good responsiveness (i.e. sensitivity to change). Effect sizes ranged from 0.44 to 1.38 for different health interventions targeting various health conditions.
  
  
  CONCLUSIONS
  The WHODAS 2.0 meets the need for a robust instrument that can be easily administered to measure the impact of health conditions, monitor the effectiveness of interventions and estimate the burden of both mental and physical disorders across different populations.
authors.affiliation: World Health Organization, avenue Appia 20, 1211 Geneva 27, Switzerland. ustunb@who.int
authors.forename: T Bedirhan
authors.initials: TB
authors.lastname: Ustün
authors.forename: Somnath
authors.initials: S
authors.lastname: Chatterji
authors.forename: Nenad
authors.initials: N
authors.lastname: Kostanjsek
authors.forename: Jürgen
authors.initials: J
authors.lastname: Rehm
authors.forename: Cille
authors.initials: C
authors.lastname: Kennedy
authors.forename: Joanne
authors.initials: J
authors.lastname: Epping-Jordan
authors.forename: Shekhar
authors.initials: S
authors.lastname: Saxena
authors.forename: Michael
authors.initials: M
authors.lastname: von Korff
authors.forename: Charles
authors.initials: C
authors.lastname: Pull
mesh_terms: D000223:Adaptation, Psychological; D004185:Disability Evaluation; D006233:Persons with Disabilities / Q000523:psychology*; D006305:Health Status Indicators; D006306:Health Surveys; D006801:Humans; D038622:Internationality; D025341:Principal Component Analysis; D016730:Program Development; D015397:Program Evaluation; D011594:Psychometrics; D011788:Quality of Life / Q000523:psychology*; D015203:Reproducibility of Results; D013315:Stress, Psychological; D014944:World Health Organization