Part of a Whole

My name is Nicolas Steenhout.
I speak, train, and consult about inclusion, accessibility and disability.

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Defining Disability – Or Trying To Anyway

I tweeted about a new study that says there are as many people with disabilities worldwide as there are people in China. This brought up the question of “What is the definition of a person with a disability?”. This is such an interesting and difficult question to answer! At first glance, it’s easy to answer – there are plenty of definitions of disability. But digging around the question a bit more, finding a useful definition that makes everyone happy isn’t straightforward at all.

University thesis have been written on the topic. I don’t claim this post will cover everything, but it will give the reader a bit of an idea.

Generally Accepted Definition

I rather like the first definition I saw of "disability". This was the definition found in the Americans with Disabilities Act. Basically, the ADA’s definition says that you have a disability if you have a condition that significantly impairs one or more activity of daily living, such as walking, seeing, eating, hearing, etc. Similar definitions are found around the world, although wording varies.

It Gets Complicated

The question was asked: "does the definition include people with glasses?". Steven pointed out that the statistics in the study would probably be quite different if it did. Indeed they would. For the purpose of most studies, mitigating factors are not considered. For the purpose of census, they sometimes are, sometimes not, and sometimes both at the same time! Another issue is one of self-perceptionsome people get upset at the idea of being labeled "disabled". Then, as @kaupapa points out, there is the issue of medical model vs social models of disabilities to be considered.

Mitigating Factors

What are mitigating factors? Simple – anything that mitigates the disability. Someone may be legally blind without glasses, hence meeting the definition of disability because they have a condition that significantly impairs the "seeing" activity of daily living. But have very good vision if they wear glasses. The glasses are a mitigating factor. Similarly hearing aids are a mitigating factor for someone who has a hearing impairment. Antidepressant medication are also a mitigating factor for someone who has depression. A wheelchair is a mitigating factor as well.

This concept has been examined in some major employment discrimination court cases, notably SUTTON et al. v. UNITED AIR LINES, INC. Basically, someone was refused a job as a pilot with United because their vision was too poor. They sued United, claiming discrimination on the basis of their “disability”. They lost the suit because they could get 20/20 vision with glasses. While they were refused a job flying passenger pilots, they could get a job flying cargo, therefore they were not “substantially limited in the major life activity of working”. As a result of the lawsuit, the definition of who qualifies as an individual with a disability was narrowed quite a bit – in the context of law and discrimination.

I think the important aspect here is the ability to "fully" mitigate a condition. While both glasses and wheelchairs are considered mitigating factors, I don’t believe they should be considered on the same level. Glasses rectify the ability to see. Wheelchairs give mobility, but do not give the ability to walk. In that respect, I find it difficult to regard glasses and wheelchairs as "equal mitigating factors". But that gets even more complex when we consider that not everyone who has a vision impairment can fully mitigate it by wearing glasses. There’s also the fact that not everyone using wheelchairs are completely unable to walk. Where do you draw the line? You don’t, you can’t.


There are many people who just don’t identify as having a disability. Many people who would meet the definition of disability (mitigated or not) just don’t perceive themselves as "disabled". I can understand that. The societal weight of wearing that label is quite heavy.

Census and Studies?

The percentage of people with disabilities has gone down according to many countries’ census. Used to be around the 21% mark. Now, it seems the average is around 17%. I don’t believe that there are less people with disabilities – I think it’s more of a reflection of how the "disability" questions are asked (or if they even are asked at all). Consider the following two questions:

  1. Do you have a disability?
  2. Do you have a condition that significantly affects activities of daily living?

Someone may not self-perceive as having a "disability", hence would answer no to question #1, but could very well identify with question #2. This impacts census data, as well as studies such as the one I originally quoted.

Disability vs Impairment

The issue of self-perception relates to a rather important difference in concepts: Is it a disability or is it an impairment? I find this distinction quite important, and it may help those people who do have a condition that affects their activities of daily living but don’t consider themselves disabled.

Such a condition is an impairment. In and of itself it doesn’t constitute a disability. An impairment becomes disabling when the person encounters barriers imposed by society. For instance, being unable to walk is an impairment. It becomes a disability only when there are no wheelchair accessible entrances in a building. Or being unable to see is an impairment. It becomes a disability when the only format made available is printed material. From that perspective, the ADA’s definition of a disability should really be called as a definition of an impairment, which can then be used to protect people from disability related discrimination. Did I mention things are complicated already?

Just like the concept of "disability" doesn’t work for everyone, the idea of "impairment" can trigger some hot reactions. Several friends of mine who are Deaf tell me that they are not hearing impaired. How could they have a hearing impairment, since they have no hearing at all. Something that doesn’t exist can’t be impaired, right?

This disability vs impairment "thing" derives in some ways from two major models of disability: medical model and social model. In the medical model, the disability/impairment is something to be erradicated, in the social model it’s just neutral. The following table highlights some major differences between the two models.

Comparing Social and Medical Models of Disability
Medical Model Social Model
Disability is abnormal. Disability is different.
Having a disability is negative. Having a disability is neutral.
Disability is found in the individual. Disability is found in the interaction between the individual and a non-accessible society.
Cure or the individual’s normalisation is the way to fix the "problem" Change to society is the way to fix the "problem".

The person who can fix the "problem" is the professional (doctor, social worker, etc). The individual, an advocate, or anyone who affects the arrangements between the individual and society can fix the "problem"

These are not the only two models of disabilities, by far. And there are new thoughts on the topic coming up. For instance, the concept of "functional diversity" is appealing because it promotes an inclusive view of the issues: everyone finds themselves on a single scale, rather than having an impairment or not.

How Useful Is The Disability Concept Anyway?

@kaupapa points out that

buying into medicalised definitions mostly misses the point

Indeed – the start of today’s discussion was thinking about "people with disabilities" when looking at tourism, and quantifying how large a market that segment of the population is. The idea is to *include* people with disabilities when developing tourism. kaupapa correctly pointed out that using medical model concepts automatically exclude – or rather creates a polarised view of the situation, which is not inclusive.

I don’t know the answer to this. I don’t think "society" is ready to effect changes without hard numbers. A business needs to know that catering to a certain market has the potential to increase revenue by X%. Getting those numbers can only be done when you define what you are counting. Unfortunately, being able to count things requires a binary view of things: either something is, or isn’t, meeting the criteria. The sliding scale of functional diversity appeals from a philosophical point of view, but appears totally impractical from a business’ need to quantify things.

What do you think is the answer? How can we provide the numbers business needs, while having a trully inclusive definition of this thing we often refer to as "disability"?

4 thoughts on “Defining Disability – Or Trying To Anyway

  1. While a very complex topic, with the right vision and drive, opportunities to enable tourism for people with disabilities are a distinct reality.

    Unfortunately, as you have pointed out, hard numbers are hard to derive when the definition is so fluid.

  2. Excellent article, Nic. Concise, yet very clear.
    Disability is a social concept. Most of our societies adhere to the medical model. “Functional diversity” is a nice concept but before our society accept social model of disability, I think it’s totally useless. Social model stresses accommodation and equal access and opportunity. We need to take that step first.
    Numbers that go by “disability” are often useless as well. Numbers that would address impairment would be more practical. What I mean is this: one can have a mental disability that doesn’t influence one’s physical access at all. 50% of people with disabilities in USA are deaf or hard of hearing. Their accommodation is very different for businesses than that of wheelchair users (regardless of why they use a chair). So the way to get the right numbers would be asking what accommodation people need. So many people need wheelchair accommodation, so many people need closed captioning, so many people need Braille menus etc. But a great part of what needs to be stressed to businesses is that accommodation is not only for people with disabilities. Any mother with a stroller loves elevators and automatic doors. Those numbers need to be also taken into account. You make a subway accessible – you make it accessible for wheelchair users, older people who have harder time, mothers with strollers, people with heavy suitcases. Everybody benefits.

  3. Kia ora, Nic.

    Experience has taught us that it’s all too easy for people to focus only on personal function rather than the broader picture and the way the *world* functions.

    The UN disability convention says “…disability results from the interaction between persons with impairments and attitudinal and environmental barriers that hinders their full and effective participation in society on an equal basis with others.”

    Always good to see thinking about other ways of understanding disability too, although functional diversity theory still seems to rely on considering disability or impairment as somehow ‘special’. Had enough of that in the education sector and charity campaigns, thanks.

    I agree with Elizabeth that our focus needs to be on fixing the world so it works well for everyone.

    Unfortunately, official thinking has often not caught up with that. Policy and statistics still focus overwhelmingly on individual and often medical characteristics as if they give all the answers. A whole lot of assumptions come into play.

    The disabled population totals vary from about 5% to about 25% by country. Factors include their level of economic development, how they ask the questions and how their citizens think about disability.

    In New Zealand our large national surveys inexplicably went from 20% for both 1996 and 2001 to 17% in 2006 – even though the questions were the same, and we know just with a rapidly-ageing population the numbers should be increasing now. Perhaps attitudes about calling ourselves disabled got worse?

    Any way you look at it, that’s a whole lot of contributing citizens who need a better-designed world to share.

  4. Very interesting post and comments. Definitions are used for different and often quite specific purposes, and, while it may be useful to have numbers for defining a market as Kaupapa says, my approach in working with organisations is once you have got past the numbers a practical understanding of the meaning of disability is more helpful. So rather than list medical conditions it is more helpful to talk about what disability means in everyday lives, and how a disabling society can be prevented. Of course the disabling society does not cover all the effects of impairment, but it does provide a useful way for both non-disabled and disabled people to feel they can do something about the situation.

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