Open AccessModeling the World Health Organization Disability Assessment Schedule II using non‐parametric item response models
Author(s) -
GalindoGarre Francisca,
Hidalgo María Dolores,
Guilera Georgina,
Pino Oscar,
Rojo J. Emilio,
GómezBenito Juana
Publication year - 2015
Publication title -
international journal of methods in psychiatric research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.275
H-Index - 73
eISSN - 1557-0657
pISSN - 1049-8931
DOI - 10.1002/mpr.1462
Subject(s) - item response theory , psychology , scale (ratio) , international classification of functioning, disability and health , sample (material) , parametric statistics , schizophrenia (object oriented programming) , schedule , clinical psychology , psychometrics , psychiatry , statistics , computer science , rehabilitation , mathematics , neuroscience , operating system , chemistry , physics , chromatography , quantum mechanics
The World Health Organization Disability Assessment Schedule II (WHO‐DAS II) is a multidimensional instrument developed for measuring disability. It comprises six domains (getting around, self‐care, getting along with others, life activities and participation in society). The main purpose of this paper is the evaluation of the psychometric properties for each domain of the WHO‐DAS II with parametric and non‐parametric Item Response Theory (IRT) models. A secondary objective is to assess whether the WHO‐DAS II items within each domain form a hierarchy of invariantly ordered severity indicators of disability. A sample of 352 patients with a schizophrenia spectrum disorder is used in this study. The 36 items WHO‐DAS II was administered during the consultation. Partial Credit and Mokken scale models are used to study the psychometric properties of the questionnaire. The psychometric properties of the WHO‐DAS II scale are satisfactory for all the domains. However, we identify a few items that do not discriminate satisfactorily between different levels of disability and cannot be invariantly ordered in the scale. In conclusion the WHO‐DAS II can be used to assess overall disability in patients with schizophrenia, but some domains are too general to assess functionality in these patients because they contain items that are not applicable to this pathology. Copyright © 2014 John Wiley & Sons, Ltd.