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

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

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.



Received on Friday, 17 July 1998 09:39:16 UTC