The report's definition gives the user a more proactive role, apparently acknowledging that it is possible for a system to comply with accessibility guidelines and standards but for a user still not to be able to use it efficiently.
Accessibility is a term that has developed very much around disability and physical and economic access [to new technologies] and this adds complexity to the situation.
Problems stemming from congenital, traumatic, medical, social or educational causes are classified under the general heading of 'Disability' but others are classified under such categories as 'Illiteracy' or 'Short attention span'. There are also many chronic conditions, such as arthritis, which cause people to have serious problems with standard information access through a PC and there are many people who, because of accidents, become temporarily incapacitated. But these two groups are not generally classified as 'disabled' people and their accessibility needs are therefore frequently not included in calculations.
The number of people who suffer from one or more of these conditions is difficult to determine because the data is produced for purposes that do not have accessible design in mind, such as epidemiological data, official disability registration, traffic, domestic and industrial accident statistics, illiteracy surveys and tax self-assessment.
Those who can benefit from accessible design or, conversely, are excluded by its absence, can broadly be split into four classes or clusters of syndromes, namely: cognitive, physical, hearing and visual. Those who could be classified as 'disabled' amount to approximately ten per cent of the population with an additional approximately 40% experiencing some kind of functional limitation in accessing digital information systems, with half of this latter group being functionally illiterate. This market segment is heavily biased towards the elderly; but many of them have substantial disposable income from employment or an occupational pension.
A lack of accessibility may arise, therefore, because a user cannot use a mouse and/or a keyboard, finds it difficult to extract basic information from a complex array, easily gets lost inside a system, and/or cannot understand the language.
Although lobbyists for accessibility generally emphasise conditions people are born with or serious conditions they acquired, the majority of people who can be classified as 'disabled' or who have functional problems with ICT are a subset of the ageing population.
The case for providing accessibility has four components:
- Moral - as citizens in a democratic society there should be equal access to data that is in the public domain or on sale as intellectual property.
- Legal - there is an increasing trend towards making accessibility a legal requirement, especially since the implementation of the Disability Discrimination Act (DDA) of 1995.
- Fiscal - those who face accessibility barriers are taxpayers and have a right to Government information and public broadcasting which they have effectively paid for.
- Market - those with accessibility problems constitute a substantial segment of the market, though where the need moves from 'accessibility' to 'inclusive design' requirements are difficult to define.
Bearing in mind the difficulty of establishing a boundary, the very minimum accessibility requirement covers the ten per cent of the population whose requirements are covered by the Disability Discrimination Act (DDA) of 1995. Typically, people with these conditions require special add-on peripherals/software to their ordinary PC systems such as:
- Refreshable Braille displays and printers
- Adjustable print size/font facilities and large page printers
- Adjustable colour, foreground/background contrast
- Audio or visual subtitling to fill gaps
- Special switches to reach a piece of information via toggle/two-way/on-off choices
- Voice-in and/or voice-out information systems
- Special input devices
- Language-simplification software.
These are usually provided by public-sector funding and are created by niche market suppliers.
Designers need to be aware of the fundamentals of access technology so that they can commission appropriate accessibility tests by specialists running their content through a variety of devices.
The key design concepts are:
- Granularity of elements - assembling pages from the tiniest possible elements, eg separating a picture and its caption.
- Labelling - clearly and concisely marking each element so that it can be isolated and manipulated, eg labelling the picture as a picture and the background as its background and the text as text.
- Multimodular multimedia - allowing the user with a sense loss in one area to access information through greater emphasis on another area, eg subtitling for deaf people.
User-initiated and machine-reactive customisation, supporting plain information with tools to alter the way the material is accessed, eg magnification.
The key technology for achieving these objectives is strict use of XML and cascading style sheets (see 'Glossary' for definitions).
Although accessibility has frequently been used interchangeably with usability (although there is a difference, as established at the beginning of this section), this does not weaken the argument that inclusive or accessible design generally benefits all users, not just those users that have been classified as 'disabled' or 'not able' by government demographics. This is an important business case to be considered by all producers.