Edited by Dr. Mark Magennis, Director, Centre for Inclusive Technology (CFIT), NCBI, Dublin, Ireland
The concept of accessibility relates to the diverse needs and abilities of a diverse section of the user population – people with disabilities – and is expressed in degrees, which range from “fully accessible”, to “partially accessible”, to “completely inaccessible. Establishing technical standards helps determine how accessible various products are. For example, the Web Content Accessibility Guidelines (WCAG 2.0) are meant to judge how accessible website content is, and give ratings on the basis of the performance of the website to certain criteria.
The author then explains how technologies like bank ATMs, mobile phones, websites, and alarms can be made more accessible.
Accessibility is a measure of the extent to which a product or service can be used by a person with a disability as effectively as it can be used by a person without that disability.
For example, if a blind person can use all the functions of a railway ticket machine just as easily as a sighted person, then that machine can be said to be fully accessible to blind people. However, a person in a wheelchair might find the same machine difficult or impossible to use. It would then be described as “inaccessible to a person in a wheelchair”. In some cases, it may be possible but very difficult for some people to use the machine, or it may be possible to use some of its functions but not all of them. The machine could then be described as “partially accessible” or even “relatively inaccessible” to those people. The exact description would depend on the extent of the problems experienced by the different types of users.
So the concept of accessibility relates to the diverse needs and abilities of a diverse section of the user population – people with disabilities – and is expressed in degrees, from “fully accessible”, to “partially accessible”, to “completely inaccessible” for a specified user group.
Where legislation, public policy or organisational policies require ICT products and services to be accessible, a recognized accessibility standard is usually referenced. Being ‘accessible’ then means complying with that standard. Accessibility standards for specific product types often attempt to quantify accessibility in measurable ways by listing required attributes, objective tests and pass/fail criteria. A good example is the Web Content Accessibility Guidelines (WCAG 2.0) which specifies testable “success criteria” for three compliance levels (A, AA or AAA), so it is possible to state objectively whether a given web page is accessible to a recognized level. The question of whether a website is “accessible” can then be answered by stating whether it complies to an agreed level (A, AA or AAA) of the WCAG 2.0 guidelines. But for many types of ICT products, there are no internationally agreed, objective and complete accessibility standards. So compliance with standards often cannot be relied on as a measure of accessibility.
In practice, accessibility is about the experiences of people with disabilities in trying to carry out the tasks for which the product is designed. The more people who can use the product, the more tasks they can carry out with it and the easier it is for them to carry out those tasks, the more accessible the product is. In essence, a product or service is accessible to the extent that its design caters for the needs of people with disabilities.
The word “accessible” has some other meanings which are not relevant here:
• “available”, as in “patients’ medical records are made accessible to them”.
• “easy to get to”, as in “the village is accessible by bus”.
• “approachable”, as in “local government officials are often very accessible”.
There are also other meanings of “accessible” which are part of what is meant here:
• “easy to reach”, as in “the light switch is in an accessible position”.
• “easy to understand”, as in "this report is readily accessible to the layperson".
The qualities of being “easy to reach” and “easy to understand” are very important for users with physical, cognitive or intellectual disabilities, but they are only one of the many qualities required for a product to be fully accessible, even to those users.
It is often easier to understand a concept like accessibility by considering some real world examples, in this case examples of inaccessibility. All of the problems described below result in some people being unable to use the product for its intended purpose. All of them could be alleviated by appropriate design.
A bank ATM
An automated Teller Machine (ATM) provided by a bank for public use may be inaccessible in the following ways:
• The machine is positioned too high, so a person in a wheelchair cannot reach some of the controls.
• The quality of the visual display is poor, with low contrast between text and background, making it difficult to read for people with vision impairments, particularly in bright sunlight.
• Prompts and responses are presented only as text on a visual display and cannot be read by blind people or people with reading impairments.
• Prompts and responses are written in complex language or jargon, making them difficult to understand for people with some cognitive or learning disabilities.
(Image above has been taken from catatronic's photostream on Flickr. CC BY SA 2.0)
A mobile phone or PDA
A mobile phone or personal digital assistant (PDA) may be inaccessible in the following ways:
• The device consists entirely of a touchscreen with no physical keys, tactile feedback or text-to-speech capability, so it is completely unusable by a blind person.
• The quality and volume of audio output is not sufficient for many hard of hearing people.
• Some built-in or third party applications do not use the accessibility API (application program interface) to make their functions and outputs available to accessibility utilities, such as text-to-speech screen reading or screen magnification software.
• A deaf person cannot communicate with the emergency services because it requires spoken conversation. Note that this is not a problem of the phone itself but the lack of a real time text-based emergency response system.
(Image above is from John.Karakatsanis' photostream on Flickr. CC BY SA 2.0)
A household intruder alarm
A typical house alarm includes a wall-mounted keypad for the householder to set or disable the alarm. This may present accessibility barriers like the following:
• The alarm indicates that it is correctly set by emitting an audible ‘beep’ without any visual signal, so people who are deaf or hard of hearing may be unable to perceive it.
• The keypad consists of small, closely spaced buttons which are difficult for a person with limited hand control to press accurately.
• Users are allowed only a limited time to input the code to cancel the alarm. This may be too short for those who are physically or cognitively slower.
Websites typically contain a mixture of text, images, links, buttons, tables, interactive forms and other content. There are many ways they can be inaccessible, including the following:
• On-screen buttons are made to respond only to a mouse click, so a person with a physical disability who is unable to use a mouse cannot ‘click’ them by pressing the Enter key on their keyboard, as is usual.
• On a payment form, the labels of input boxes and controls (e.g. ‘name’, ‘choice of payment method’) are displayed in a way that cannot be read by the text-to-speech software used by a blind person, so this person does not know the purpose of each box or control.
• Visual design and layout are inconsistent from page to page, making the website confusing and difficult to learn for people with some cognitive or learning disabilities.
• Online videos have no captions (subtitles), audio description tracks or text transcripts. So deaf, hard of hearing and blind users do not have access to the full content.