Complex: The more complex method of scoring is called ”item-response-theory” (IRT)—based scoring. It takes into account multiple levels of difficulty for each WHODAS 2.0 item. It takes the coding for each item response as "none,” ”mild,” ”moderate,” ”se- vere," and ”extreme” separately, and then uses a computer to determine the summary score by differentially weighting the items and the levels of severity. The computer pro- gram is available from the WHO Web site. The scoring has three steps: 0 Step l—Summing of recoded item scores within each domain.
0 Step 2—Summing of all six domain scores.
' Step 3—Converting the summary score into a metric ranging from 0 to 100 (where 0=no disability; 100=full disability).
WHODAS 2.0 domain scores. WHODAS 2.0 produces domain-specific scores for six different functioning domains: cognition, mobility, self—care, getting along, life activities (household and work/school), and participation.
WHODAS 2.0 population norms. For the population norms for IRT-based scoring of the
WHODAS 2.0 and for the population distribution of IRT-based scores for WHODAS 2.0, please see www.Who.int/classifications / icf/ P0p_norms_distrib_IRT_scores.pdf.
The clinician is asked to review the individual’s response on each item on the measure during the clinical interview and to indicate the self—reported score for each item in the sec- tion provided for "Clinician Use Only." However, if the clinician determines that the score on an item should be different based on the clinical interview and other information avail- able, he or she may indicate a corrected score in the raw item score box. Based on findings from the DSM-S Field Trials in adult patient samples across six sites in the United States and one in Canada, DSM-5 recommends calculation and use of average scores for each domain and for general disability. The average scores are comparable to the WHODAS 5-point scale, which allows the Clinician to think of the individual’s disability in terms of none (1), mild (2), moderate (3), severe (4), or extreme (5). The average domain and general disability scores were found to be reliable, easy to use, and clinically useful to the clinicians in the
DSM-S Field Trials. The average domain score is calculated by dividing the raw domain score by the number of items in the domain (e.g., if all the items within the "understanding and communicating” domain are rated as being moderate then the average domain score would be 18 / 6:3, indicating moderate disability). The average general disability score is cal- culated by dividing the raw overall score by number of items in the measure (i.e., 36). The individual should be encouraged to complete all of the items on the WHODAS 2.0. If no re- sponse is given on 10 or more items of the measure (i.e., more than 25% of the 36 total items), calculation of the simple and average general disability scores may not be helpful.
If 10 or more of the total items on the measure are missing but the items for some of the do- mains are 75%—100% complete, the simple or average domain scores may be used for those domains.
Frequency of use. To track change in the individual’s level of disability over time, the measure may be completed at regular intervals as clinically indicated, depending on the stability of the individual's symptoms and treatment status. Consistently high scores on a particular domain may indicate significant and problematic areas for the individual that might warrant further assessment and intervention.
\ WHODAS 2.0
World Health Organization Disability Assessment Schedule 2.0 36-item version, self—administered
Patient Name: Age: Sex: El Male CI Female Date: