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The Invisibility of Disability

by Alexander Dawson
8 min read
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Addressing the gaps in the existing frameworks that define disability with a more inclusive approach.

Highly publicized lawsuits and an increased awareness of disabled users’ needs have caused a much-needed improvement in attitudes toward accessibility. The general need for accessibility standards has set the foundations of the Web Content Accessibility Guidelines (WCAG), but there’s still a general lack of understanding of what constitutes a disability. While some acknowledged needs are being catered to, many still remain invisible and beyond the perception of web and UX designers. The failure of defining such instrumental needs requires addressing.

Debilitating Definitions

Laws have been interpreted and adapted, best practices and guidelines have been published, and the Web is evolving to meet disabled users’ needs. However, the concept of what counts as a disability is to some extent being fragmented. Instead of understanding how, why, and in what ways people are affected, we seem to be viewing accessibility as a challenge that can be solved by simply following predefined and incomplete checklists.

I’m not asserting that the Web Accessibility Initiative (WAI) isn’t doing good work (because they really are), but limiting the scope of accessibility to only what’s specified in the WCAG is problematic. It will prevent product designers from seeing the bigger accessibility picture, in which everyone is, or will be at some point in their lives, disabled and have their own unique requirements and limitations.

The concept of accessibility (in the same vein as usability) cannot be defined or packaged into short-term achievable goals that cover every requirement. An infinite range of variables exists that can affect humans, and such an array of needs cannot be accounted for or defined by strict specifications. While current definitions are maintained, the consequence may result in designers worldwide failing (over the long term) to consider the wider existing scope of requirements.

Much of the confusion about accessibility arises from the large number of guidelines, specifications, and laws that exist to promote good practices. A product designer can use the Americans with Disabilities Act (ADA), Disability Discrimination Act (DDA), Publicly Available Specification 78 (PAS 78), Section 508 of the U.S. Rehabilitation Act, or WCAG as guides, but the scope of the problem is global. Lack of standardized definition of the ways and degrees to which people may be functionally limited makes the context of disability rather ambiguous.

The web design community currently struggles to understand how people are impaired when using the Web, making it impossible to account for and cater to the needs of those individuals. The difficulty is due to a fear of not knowing how to resolve the needs of disabled users, and because of uncertainty about how fully and completely the disability guidelines and specifications like the WCAG describe the spectrum of disability.

Chronically Acute

I come from a Health and Social Care background where individual needs are considered paramount. This is, of course, something accessibility advocates have also been promoting for a long time. My definition of accessibility has been largely shaped by my work with those who are directly affected by the common and prevalent accessibility problems of websites. Based on my experience with how disability is defined beyond the Web, the most promising way forward in accounting for a wider range of needs is to replace existing models with ones that are less tightly linked to commonly employed best practices.

The obvious needs of the blind, deaf, and motor function deficient (amongst others) are accounted for by accessibility specifications like WCAG. But a wider range of barriers that may impair visitors remain largely unrecognised by web designers as a result of the failings of standards like WCAG. For example, a broken arm constitutes a disability that, though temporary, isn’t accounted for in accessibility standards and thus isn’t factored into web design, even though its disabling effect is considerable and it’s statistically likely to affect a great many individuals.

Understanding disability as comprising both acute and chronic conditions that impair the visitor’s abilities provides a much less discriminatory perspective on a site’s general accessibility quality. This goes beyond current definitions of accessibility, but it more accurately describes the variables at work. In the case of a broken arm, the concomitant physical limitations should qualify the individual as being impaired, but existing accessibility standards don’t account for such a disability’s existence.

Mechanical PIES

Most web designers find the idea of accessibility daunting. Accounting for endless medical conditions, impairments, and barriers requires an almost encyclopaedic knowledge of medicine. Therefore, rather than portraying accessibility as a large range of medical conditions, we should redefine the concept in terms of the factors that result in a disability. And these factors should, in turn, work in line with current accessibility practices.

In this section, I propose a redefinition of the model of ability that, while perhaps rather simplistic on its face, should support a more comprehensive awareness of the more extensive range of potential disabilities. The full range of categories, scopes, and levels of potential impairments are of legitimate concern and should be accounted for in accessible product design.

My model adapts a recognised medical model (of health and social care) known as PIES that’s used to represent the physical, intellectual, emotional and social needs of individuals. I add a mechanical element to account for technology-related issues such as Internet connection speed, and I’ve outlined additional factors such as the scope (timeframe) of the disability and the degree to which it affects the user. Both of which are taken into account through medical diagnosis and both increase the recognition of how diverse and complicated accessibility needs can become.

Categories of disability:

  • Physical – Affects the human senses and any visible level of interaction such as visual, aural, speech, motor, seizure, or age-related problems, as well as other physiological conditions.
  • Intellectual – Affects knowledge level and cognitive processing such as cognitive, memory, lingual, learning (literacy and associative), and educational or knowledge-awareness issues.
  • Emotional – Affects perception, psychological state, and mental endurance, and includes psychological, nervous (stress and anxiety), attention-related, and behavioral issues.
  • Social – Affects brand attachment, interaction, and idealistic association and includes issues related to findability, communicative or sociological barriers, assistive relevancy, and environmental issues.
  • Mechanical – Variable, disabling factors related to the user’s particular quality of and access to technology, such Internet availability, speed, and latency; software issues like browser quality, plug-in dependence, etc.; and hardware quality issues such as slow devices, broken input devices, or small displays.

While traditional definitions of accessibility focus on medical conditions, in digital mediums such as the Internet where a computer acts as an extension of the body, accounting for mechanical issues is justified. As an example, a broken display is digitally equal to vision loss (as a barrier to access).

Scope of disability:

  • Chronic – A long lasting, possibly permanent impairment or disability.
  • Acute – A short term, temporary impairment or restrictive issue.

Level of disability:

  • Mild – Restricts or inhibits to a small nagging or annoyance level in the course of a session.
  • Moderate – Affects to the extent that alternative content and control mechanisms are required.
  • Severe – Requires explicit support or specialized accessibility aids.

As is apparent in the example of the broken arm, the need to account for the widest possible range of issues for our audience is clear. In the field of web design, the above model has some essential practical applications. By accounting for the needs of someone who, for example, suffers from social anxiety (a social disability not covered by WCAG) you could potentially encourage a greater level of interactivity.

In addition to acknowledging the increased range of disabilities, accounting for short-term problems or mild impairments (which are often ignored) could lead to better user experiences as an increased focus will be placed on accounting for factors that interfere with user interactions. Disability is more than the simple loss of function; there are many levels of disability and many forms of severity. In the same way that being colorblind isn’t equal to complete blindness, we need to alter our perceptions that disability is a rare situation that is readily apparent.


Within the WCAG “layers of guidance,” it is noted that whilst attempts are made to cover a wide range of accessibility issues, even at the highest level (AAA) there will still be people who may be affected by issues that cannot easily be documented or accounted for (with a common solution). The key goal of my Mechanical PIES model isn’t to change the way in which we undertake accessibility testing (in the sense of providing handy solutions and best practices). Instead, it aims to highlight where those needs may exist and to encourage the development of more holistically inclusive solutions.

The Mechanical PIES model solidifies the otherwise abstract nature of impairments, and more adequately defines the wider spectrum of physical, intellectual, emotional, social, and mechanical issues that affect human-computer interaction (HCI) and the Internet of the future. Future versions of WCAG or other specifications could draw upon this and place additional emphasis on testing beyond the A/AA/AAA “validation” idea, and an increased level of awareness could be drawn toward the consequences of failing to resolve of such issues.


The key to accessibility (and usability) is ensuring that websites can be accessed and used by the widest possible audience, no matter their level of ability. While specifications and laws exist, their scopes are too limited and they only guide designers toward adopting basic best practices. Many people take the complications of disability too lightly and think it only affects a small portion of their user bases. But accounting for the needs of those affected by disabling conditions (who are much more than an edge-case minority) brings us to a surprising conclusion that can’t be ignored: at some point in our lives, we all have, or will, suffer disability!

Think back to times in your life when your access to technology or your physical abilities were affected, or when you were less able to accomplish ordinary tasks. Everyone, regardless of background, has been affected directly or indirectly by disability. Perhaps the disability occurred over a short period (such as a broken limb), or perhaps it was a more chronic condition (such as arthritis), but everyone has been affected by limitations at some point in their lives.

While the model of ability I’ve described in this article is probably too abstract for demographical and statistical analysis, the conclusion I draw is that everyone is disabled (or will suffer it at some point in their lives), and the extent of that disability shouldn’t matter; addressing any barrier to access should be of critical importance. We should consider the challenges of addressing accessibility more carefully and evolve the existing specifications and perspectives to better reflect a fuller range of disabilities. After all, at some point in each of our lives we will become (or already are) the individuals needing such conventions and aids.

post authorAlexander Dawson

Alexander Dawson, Alexander Dawson is an award winning, self-taught, freelance web professional, writer, published author, and recreational software developer from Brighton (UK). With more than 10 years of industry experience he spends his days running his consultancy firm, HiTechy, on Twitter @AlexDawsonUK, writing professionally about web design, and giving his free time to assist others in the field. In recent years, Alexander has become an established web writer providing articles for some of the industry’s most respected sites including Smashing Magazine, Six Revisions, and SitePoint (where he also assists other web designers regularly through their popular forums). In addition, as a member of the Guild of Accessible Web Designers he actively promotes and advocates the benefits of a good user-experience and web standards. When Alexander isn’t coding or writing about design and development, he enjoys a game of tennis (or chess) and watching movies.


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