The WG question sets were developed for use in censuses and surveys according to the Fundamental Principles of Official Statistics.
The questions reflect advances in the conceptualization of disability and use the World Health Organization’s International Classification of Functioning, Disability, and Health (ICF) as a conceptual model.The focus is on functioning in basic actions in contrast to approaches that are based on a medical model which focus on impairments or bodily functions. Question testing has shown that they produce internationally comparable data.
The question sets are designed to identify the population that is at a greater risk than the general population of experiencing restrictions in social participation, for example in employment, education or civic life.
The WG questions sets are designed to provide comparable data cross-nationally for populations living in a variety of cultures with varying economic resources. The objective is to identify persons with similar types and levels of limitations in basic actions regardless of nationality or culture.
Using the Short Set of Questions in conjunction with other questions on a census, it is possible to compare the actual level of participation of the population at higher risk with those not experiencing similar functional difficulties. Observed differences in levels or degree of participation reflect the need for societal accommodation to equalize opportunities for full societal inclusion. This approach to disability is a central tenet of the UN Convention on the Rights of Persons with Disabilities.
It is intended that the Short Set will identify the majority of persons in the population who are at greater risk than the general population of experiencing limited or restricted participation in society. The questions cover six functional domains or basic actions: seeing, hearing, walking, cognition, self care, and communication. Each question has four response categories: (1) No, no difficulty, (2) Yes, some difficulty, (3) Yes, a lot of difficulty and (4) Cannot do it at all. The severity scale is used in the response categories in order to capture the full spectrum of functioning from mild to severe.
The six domains cover many but not all areas of functioning. Furthermore, the response categories capture the degree or severity of the difficulty experienced. Multiple disability scenarios can be described depending on the domain(s) of interest and the choice of severity cut-off. There is more than one way to capture disability through the application of this set of core questions; resulting in not one but several possible prevalence estimates.
The WG has a methodology for testing the questions both cognitively and in the field. This ensures the questions are being interpreted consistently across countries and are capturing the data they are intended to.