- From: Kevin Carey <humanity@atlas.co.uk>
- Date: Fri, 17 Jul 1998 14:38:21 +0100
- To: <w3c-wai-eo@w3.org>
- Cc: "William Loughborough" <love26@gorge.net>, "Judy Brewer" <jbrewer@aol.com>
Email to: WAI EOWG list Copies: Judy Brewer; William Loughborough Subject: Demography Date: 17.vii.908. What demographic data is required to make a coherent business case for accessibility to the World Wide Web? The summary answer to this question is that data on functional mis-matches between people and technology. To take one instance, the more flexibility in on-screen text presentation - magnification, font, contrast - the fewer mismatches there will be between the technology and people with partial vision. Such data allows business and the public sector to determine to what extent any modification to a 'standard' design is economically justified from the point of view of the manufactuer on the one hand the public on the other. Again, using the example of flexible on-screen presentation, as this is very cheap to implement at the design stage (though more expensive as a retro-engineering operation) it presents manufactuers with a larger market without much expense and it equally provides a desirable attribute in the contextr of public sector approval/purchase without buyers being put to very much extent; a Braille bar, on the other hand, is extremely expensive - as much as the aggregate cost of the rest of the kit - but will only be used by a tiny fraction even of what is classified as the "blind" population; you are then in the situation of wanting to compare the cost of the accessibility with the likely market from which you determine not whether the access should be provided -as it should of right - but rather whether that access should be INTEGRAL to the standard system or simply whether the standard system should be designed in such a way to allow access from an add-on PERIPHERAL. Data on disability, then, should not be classified according to traditional, cultural clusters of syndromes (I say "cultural" because classifications like "blindness" and "physical disability" are not rational classifications) but, rather, what is needed is an understanding of functional limitations, how these limit access to technology, what is needed to bridge the gap, how many people need a particular gap bridged; from there a discussion can take place about the integral/peripheral criteria by establishing some sort of rough line where uptake/cost reaches a critical point. Of course, there is hardly any such data. On a solely demographic basis, the easiest method to caputre the maximum number of people suffering potential mismatches is to conduct detailed research on people over the age of 60; contrary to the outpourings of charity fund-raisers, most people who suffer from functional limitations do not do so from congenital or traumatic, severe childhood causes, most people who suffer a decline in their functional abilities do so gradually and from the age of 60 onwards. Of course, once the potential user market is introduced as a factor, the picture will change slightly. There is, though, a danger of there being a severe misunderstanding of IT use measured by age. There is an anachronistic assumption that the primary access to IT will be through PCs whereas it will soon be through televisions. Although it is only fair to point out that telebanking and teleshopping have the potential, if they replace traditional outlets, for isolating older and disabled people, they will also be a great boon to those who choose not to go out often. The case, then, for the need for accessibility can be based firmly on the whole population rather than, as has been necessary until now, concentrating on access to IT as a PC-based phenomenon. What do we already know? It is not difficult to find data on traditional, cultural clusters of syndromes but most of this data is medically based and needs to be handled carefully. To take visiual impairment and blindness; setting to one side that there is no common definition for these terms used internationally (the richer the country and, therefore, the less in need of population-based epidemiological surveys as the basis for planning, the less likely it is either to collect good data or to use the World Health Organisations), most visual impairment is measured according to what people can see at three metres or more distant; this, of course, only provides partially useful data for what people do inside three metres which is where most screen access, for instance, takes place. Even so, by looking at the medical data carefully, segmenting it by age and morbidity classification, it is possible to arrive at figures for broad areas of limited functionality by age for most populations. In the case of Europe and the United States of America, for instance, it will be possible to produce figures which indicate the need for screen presentation flexibility that is great enough to justify its incorporation into general design. The real problem with the medical data is that it is extremely bad at tracking temporary functional limitation from road accidents, possession of the wrong spectacles, back problems, arthritis &c. This is a large segment of the population with a surprisingly high percentage below the age of sixty; these figures can be derived from data on absence from work. In summary, then, whilst we don't want the rather banner headline United nations figure of "1 in 10", we do need broad numbers that relate to functional limitations which require adjustment to existing systems and changes incorporated into basic design in future systems. On the basis of the discussion at the EOWG next week in England I am prepared to take this further. Yours KEVIN CAREY
Received on Friday, 17 July 1998 09:39:16 UTC