Disability Models and Measures

1. Disability Models and Measures Sophie Mitra Fordham University mitra@fordham.edu Conference: Improving the measurement of disability and the physical access of the disabled: Lessons from international experience, February 10, 2012 Moscow, 27 September 2011

2. - The Medical Model - The Social Model - The Nagi Model The ICF (International Classification of Functioning, Disability and Health) Part 1. Models used to Define Disability

3. The Medical (or Bio-Medical) Model • The medical model considers disability as a problem of the individual that is directly caused by a disease, an injury or other health conditions. • The medical model locates the problem with the person. A person is in the ‘sick role’ (Parsons, 1975). • This model is strongly normative. • The major concern at the political level is to provide health care and rehabilitation services.

4. The Social Model • Disability is not a problem of the individual, it is a problem created by the social environment and requires social change. • This model has many different versions. We review briefly below two versions. • The UK social model: At the heart of this model lies societal oppression (Oliver, 1990).

5. The Social Model (Cont.) • The oppressed minority model. Persons with disabilities face discrimination and segregation through barriers in the environment. Their experiences are therefore perceived as similar to those of an oppressed minority group. Social inequalities encountered by persons with disabilities are considered as similar to those encountered by other minorities (Hahn, 2002, p. 171).

6. The Nagi Model • The Nagi model is widely used in the economics of disability field. It identifies functional limitations as the restrictions that impairments impose on the individual’s ability to perform the tasks of his or her roles and normal daily activities. • Disability is a social construct. • For instance, a 12-year old girl with mental retardation does not attend school, she stays home with her parents helping with household chores.

7. The ICF model

8. Disability under the Capability Approach: • Disability has been defined in terms of capability or functioning deprivation (Burchardt 2004; Mitra 2006; Morris 2009; Terzi 2005; Welch 2007) • Disability occurs when an individual is deprived of practical opportunities or functionings as a result of an impairment or health condition.

9. The Capability Approach is a holistic approach It accounts for the variety of factors that may lead to disability. In particular, the Capability Approach recognizes that poverty can be the cause of disability.

10. Part 2. Disability Measures • Disability is difficult to measure. • There is no gold standard measure. • Disability measures vary depending on research and policy objectives.

11. Disability Measures (Cont.) I focus on disability measures that use household survey or census data with questions on: • Impairments. • Functional limitations. • Activity limitations. • A combination of the above.

12. Impairment Measures • Impairment measures of disability focus on the presence of impairment intrinsic to the individual. • For example, individuals may be queried about blindness, deafness, mental retardation, stammering and stuttering, complete or partial paralysis.

13. Functional Limitation Measures • Functional limitations refer to difficulties experienced with particular bodily functions such as seeing, walking, hearing, speaking, climbing stairs, lifting and carrying. • The above two measures of disability, impairments and functional limitations measure disability as per the medical model and capture problems in body functions and structures under the ICF.

14. Activity Limitations Measures • Activity limitations are limitations in activities of daily living (ADL) such as bathing or dressing. • Activity limitations may also include participation limitations in major life activities such as going outside the home, work or housework for working age persons, and school or play for children. This measure may be considered to capture disability as per the social model as well as the activity limitations and participation restriction under the ICF.

15. Different measures lead to very different prevalence estimates • Chile is an interesting case where estimates are available for both impairment and activity limitation measures. The impairment prevalence rate is almost 10 times lower at 2.2% than the activity limitation rate at 21.7% (IDRM 2004). • In South Africa, estimates vary from a low of 3.7% in the 1999 October Household Survey, to a high of 12.8% in the National Health and Population Survey where chronic illnesses were counted as disabilities (Emmett (2006)). CASE (1999) is the only study specifically designed to measure disability prevalence and assess the well being of PWDs. In this study, in 1997, disability prevalence stood at 5.9%.

16. Examples of disability questions: • India NSS 58th 2001: A person is considered disabled “if the person has restrictions or lack of abilities to perform an activity in the manner or within the range considered normal for a human being.” • South Africa GHS 2010 ‘Is the person limited in his/her daily activities at home, at work or at school because of a long-term physical or mental condition lasting six months or more?’

17. Examples of disability questions (Cont.): • India Census 2001:“If the person is physically/mentally disabled, give appropriate code number from the list below: in seeing, in speech, in hearing, in movement, mental.”

18. Washington Group Short Disability Measure

19. Identification of persons with disabilities: Disability score and cutoff e.g. WHO-World Bank (2011) • Challenges in calculating a score • Challenges in setting the cutoff

20. Identification of persons with disabilities for a given measure (Cont): Use of self-reported severity: for instance, persons reporting severe or extreme limitations are identified as having a disability (Mitra, Posarac & Vick 2011; Loeb, Eide & Mont 2008) Note: Mild and moderate limitation self reports are not as reliable as severe/extreme (Lafortune et al 2007; Miller et al 2010).

21. Main sources IDRM (2004), Regional Report of the Americas, International Disability Rights Monitor, International Disability Network, Chicago. Lafortune G., G. Balestat and the Disability Study Expert Group Members (2007) Trends in Severe Disability among Elderly People: Assessing the Evidence in 12 OECD Countries and the Future Implications. OECD Health Working Paper 26. Loeb M E, Eide A H, Mont D (2008) Approaching disability prevalence: the case of Zambia. European Journal of Disability Research. 2, 32 - 43.       Miller, K., D. Mont, A. Maitland, B. Altman, and J. Madans. (2010). “Results of a Cross-national Structured Cognitive Interviewing Protocol to Test Measures of Disability.” Quality and Quantity 45(4): 801-815, DOI: 10.1007/s11135-010-9370-4. Mitra, S. (2006) The Capability Approach and Disability, Journal of Disability Policy Studies, 16, No. 4, pp. 236-247. Mitra, S., Posarac, A. and Vick, B.. Disability and Poverty in Developing Countries: a Snapshot from the World Health Survey (long version:World Bank Social Protection Working Paper series 1109). WHO and World Bank (2011). World Report on Disability. Geneva: World Health Organization and World Bank.

22. Thank you! mitra@fordham.edu www.fordham.edu/economics/mitra/