Before embarking on the major strands of my argument it would be as well to consider definitions.
There is now a fine old Pharisaic, or perhaps we might better say Scholastic, discussion about the delineation of accessibility - the capability of a system to cater for the needs of disabled people - as a highly specific segment in the usability - the capability of a system to behave in a way which most closely accords with human behaviour - sector as a whole. This is best imagined as an accessibility core versus a usability outer section, with accessibility accounting for the most severe functional gap between person and system but the division defies the tactics of conventional turf wars. Whereas execrable taxonomy, for example, the most salient and frequent shortcoming of Web sites, is usually classified as a usability issue, the inability to use keyboard input, as opposed to the use of the mouse, is classically an accessibility issue; but good accessibility through the use of the keyboard, can overcome bad taxonomy. What we have learned, most notably in the framework for the outstanding Disability Rights Commission (DRC) research on Web accessibility , is that the key issue for those experiencing problems with digital information systems is the unified concept of task completion whose use of time and success rate can be measured, as opposed to much more abstract measurements of accessibility and usability. Only those who seek grants to split hairs will quarrel with the fundamental premise that what matters is the system's fitness for purpose which allows, for example, box offices to issue tickets, shops to sell goods and information systems to inform. On this basis, then, one should properly refer to task completion in the context of a functional gap between digital information systems and people but, having recognised this, I will use the traditional language of 'Accessibility' as it refers in a shorthand way to the problems that disabled people experience with information systems but this shorthand will embrace some characteristics which are often described in terms of 'Usability'.
For brevity, let us assume that the core of people who experience accessibility problems as the primary barrier in their use of digital information systems are classifiable as 'Disabled'. Admittedly, this term is usually epidemiologically or administratively defined whereas many disabled people would prefer it to be self-referential; but for the purposes of this article, I will assume the hybrid schedule of definitions in the Disability Discrimination Act (1995) , as amended by the DDA (2005) . Whatever definitions are used, I believe that the following propositions are beyond dispute:
These figures are related to PC-based systems largely presenting text and static graphics; one would expect the ranking to alter, with problems for deaf and hearing impaired people increased, with the growth of multimedia products without sub-titling.
As already noted, it is dangerous to define accessibility, as opposed to usability, features in the enabling of task completion but the following is a summary, most of which is embraced by the idea dealt with later of creating data multi-modally; the exception is in the area of enabling simplification which is primarily required for those with learning, cognitive and developmental difficulties. The terms in brackets show where the original technique was developed but all of these will move in time across channels:
The second major issue of definition is my use of the term digital information system. This generic description is necessarily much wider than the usual concern with Internet and Web access. Public policy in the area of social inclusion or the 'Digital divide' has erroneously concentrated on PC-based, as opposed to telephone and television-based, user interface experiences out of historical snobbery but the necessary analogue boundaries between the three channels will disappear and so it is much more helpful to think of digital information systems generically. One of the conclusions which will naturally emerge from this discussion, incidentally, is that Internet publishers have much to learn from broadcasters about the culture of accessibility whereas broadcasters have much to learn from Internet publishers about plasticity and interactivity.
Finally, on the subject of definition, I have already used the term 'functional gap' to describe the inadequate transactional outcome between digital information systems and people. I use this term most deliberately because the public policy analysis of why people have problems with digital information systems, notably those dependent upon the PC, has been predominantly anthropocentric. If only, politicians say, we could get alienated people to master word processing, the world would be a better place.
Regardless of whether or not this is true, the much more crucial issue is why these people have problems with PC/Windows bundles when they have no problems using VCR equipment, navigating the Sky Electronic Programme Guide, manipulating mobile phone settings, using SMS or, in a different field, passing a driving test, understanding the soccer off-side rule and finding items in supermarkets.
We should see this functionality gap as arising because of two major factors: the lack of skills or incentive on the part of the human user on the one hand, and the deficiency in the design of the system and its user interface on the other. There is, to cite an apparently trivial example, something perverse about a system which requires the activation of the 'on' switch to turn it off. Computer users with an incentive to master a system, easily forget its perversity until it either spontaneously modifies itself or an accidental operation is performed where in either case the correction is not susceptible to rational investigation. In a fundamental sense, almost universally overlooked by analysts and lobbyists who have an obsession with skills development, training in the use of systems is a cost shift from the producer to the consumer; the better the design, the more intuitive the functionality, the lower the degree of skill and training which are required to close the gap between system and user.
In considering the functionality gap between disabled people and digital information systems, I will deal with three fundamental issues:
Having considered these general issues I will make some specific remarks on accessibility in the context of the formal learning process.
The extent and degree of accessibility of digital information to disabled people is in inverse ratio to the extent and degree of legislation and regulation governing its publishing or broadcasting; thus:
Indeed, broadcasting is a good starting point for an accessibility discussion because as a medium it inherited the cinematographic tradition of creating its content multi modally, that is using moving pictures, static text and graphics and music and audio simultaneously. This practice, when deliberatively enhanced to include text sub titling for deaf and hearing impaired people and audio description for blind and visually impaired people, fulfils the first basic rule for creating accessible digital information:
Where broadcasting has, on the other hand, been conspicuously less accessible is in the area of user control. There are two reasons why broadcasting tends not to think in terms of plasticity: first, it was born in an analogue era and, even more significantly, it deals in intellectual property where a high value is placed on integrity. Unlike the Internet environment which is a product of the digital age and which frequently aims to generate interaction with the system, broadcasting has only encouraged interaction through the use of different back channels such as mailed letters, the telephone and most recently email.
Paradoxically, the area where there is least plasticity in digital information available on the Internet is in the public sector whose stated mission it is to communicate effectively with all citizens. The Portable Document Format (PDF) is ideally suited to curtail the interference with documents and maintain their integrity and so it has precisely the opposite characteristics from a fully accessible document which allows the user to choose foreground and background colours, print size and font, etc. There is now a comprehensive PDF accessibility package but in general the format performs less well in accessibility terms than standard Microsoft documents. At the other end of the spectrum accessibility is being threatened by the increasing use of image files such as Graphics Interchange/tagged image file formats GIF/TIF) which contain text. There will be a further challenge when Internet standards are set by global entertainment companies with the primary purpose of delivering entertainment rather than by text and static graphics publishers.
There are many standards and rules which attempt to capture the various aspects of digital information accessibility  but these boil down to a simple principle:
The long-term future of digital information accessibility lies in the development of authoring tools which prompt good practice. There is also the possibility that broadcasters, accustomed to conforming to regulated accessibility criteria, will seek a 'level playing field' in the context of convergence to ensure that their competitors comply with accessibility standards. There is a good deal to be said here for cross-fertilisation: broadcasters can learn from the Internet culture of plasticity and interactivity and Internet publishers can acquire the accessibility culture from broadcasters.
A further aspect of digital information design involves the adoption of a neutral stance with respect to channels and their user interfaces. A good example of this is the need to design Web pages in such a way that they are appropriate for a high resolution PC screen but can be simplified, through the use of tools, so that they are suitable for the small screen of a mobile phone; this might involve, for example, using a tool which works on a macro for eliminating illustrative graphics for the smaller screen. This kind of channel and user interface flexibility is summarised in my third general rule:
Taken together, these three general principles of creating multi modally, enabling customisation and simplification and enabling channel and user interface choice call for an approach to digital information design and content creation which constitutes a radical departure from most analogue practice. In this context there are three fundamental characteristics of the way in which digital information is designed which must be borne in mind:
Creative collaboration has been a salient feature of the cinema and television but it has made relatively little headway in traditional and in Internet publishing. It would be preposterous to suggest that an individual could make a television programme single-handed but almost as preposterous in our culture to suggest that a major piece of text fiction could be created collaboratively. There is a tradition of book illustrators working with authors but there are still a very large number of Web sites being designed and built by individuals, even though a high aesthetic sense is rarely matched by a deep insight into taxonomy. There is also a marked tendency, repeating the mistakes of television with cinema products, to transfer text intended for printing to an on-screen environment instead of writing specifically for the screen.
Data granularity is essential for customisation and simplification and for the selective application of tools. In the analogue era the objective was to take granular data and to render it in a holistic, bound format to preserve its integrity. With digital data it is much more helpful to assemble all the elements but enable them to be discretely manipulable, e.g. a user may wish to leave unaltered the background to an etching but sharpen the foreground outline but if the two layers are 'bound' they cannot be modified and rendered separately. A much more important example in our context is the separation of on-screen text elements from the graphics file of the picture, enable text enlargement, simplification or audio rendering.
In the analogue age the data did not come with manipulation and rendering tools but these should be seen as an integral part of any document so that the user can customise the rendering. Data creators, aggregators, brokers and publishers generally assume that the user has access to standard tools, although this frequently does not apply in the area of summarising and simplification (and altering browser settings can be difficult) but the separation in the broadcasting field is radical; there have been instances where regulators have insisted upon the creation of audio-described broadcasting although receivers lack software to decode the extra material. As the access to digital data penetrates further into 'lower' socio-economic markets, the need for integrated tools will increase.
The lack of integrated data manipulation tools has a particularly damaging effect on disabled people. Microsoft, as a near monopoly supplier of computer operating systems and software, insists that to bundle accessibility into its standard offer would be a breach of competition law. Unfortunately, accessibility software such as 'Screen readers' and screen magnification software is supplied by a tiny handful of developers operating in a cartel on low R&D budgets. Their products work most reliably in 'turnkey' hardware which is expensive relative to the standard PC/Apple market but if the software is used on standard systems there are compatibility problems. In the broadcasting market access to audio description involves the use of an additional set top box or card.
Although, strictly speaking, a hearing aid is a data user interface, I will not be dealing with this class of item but will focus on:
The chief problem with all user interface control panels is that they are non-standard. The European Union made a serious error with disastrous but unintended consequences for disabled people when it deregulated hardware design except in respect of health and safety requirements. The open market in design has left disabled people increasingly impotent as technology has miniaturised and become less standardised. Many people with poor vision or learning problems, for example, find it very difficult to learn how to use a qwerty keyboard but their problems are complicated by layout variations outside those keys which are absolutely standard. Even where the numbers layout 0-9 is standard across a large number of numeric keypads, the exact location of these ten buttons varies, as do the associated features on remote controllers and telephones. A blind person checking into a hotel may find herself both unable to use the television and unable to call for help!
The obvious answer to the problem with qwerty-centred keyboards and numeric keypads is the individual, all purpose, programmable user interface which can be 'BlueToothed' to any processor and/or receiver. This might take the form of familiar-looking devices with customised key assignment but in many cases the device will be a flat surface with programmable and movable buttons which might, for example, deliberately limit the user to five television channels instead of the approximately 400 on current Sky electronic Programme Guides. Such a user interface would allow for the organic development of functionality based on user need and user skill. It would overcome one of the greatest obstacles to accessibility at a low cost and would eliminate a substantial amount of hardware duplication.
The same principle applies to screen technology. The physical separation of the screen from the processor offers a wealth of opportunities for heightened accessibility. A user could carry her own screen or portable screens of a variety of specifications could be provided in public places. Again, connectivity could be through Blue Tooth or a similar convention.
For some people the personal screen and the programmable user interface could be a single device.
In either case, the cost of acquiring these devices would be much less than that of duplicated hardware.
As has already been noted, there is much to be gained from convergence in the creation, transmission, reception and processing of digital content, particularly if the industries emerging from the analogue era can learn from each other and can, in addition, develop new standards.
In this context, the mobile telephone industry provides a very good case study. It has developed some data organisation ideas (menus) from the computer sector but it is already beginning to behave like an entertainment library and a broadcaster; but at the centre there is voice and text interaction, combining the traditional telephone use with revolutionary SMS. Related to this are developments in text to speech and speech to text which constitute a fundamental component of accessibility, particularly in respect of the second half of the multi modality principle, namely enable multi modal interaction.
Thus, although there are two distinctive traditions in broadcasting on the one hand and publishing on the other, the key driver for convergence may be the telephone which borrows from both traditions. What it lacks is an accessibility regulatory framework similar to that of broadcasting or a self-regulatory framework similar to that for the World Wide Web.
In summary, then, all the components for effective accessibility in a converged digital data ecology exist but they need to be creatively combined.
Over and above the general problems of accessibility, there are some specific problems which need to be considered largely in the context of formal learning, although these present themselves in the general digital information environment:
For disabled people, even more than for the population in general, navigation is a crucial issue. Most disabled people are measurably slower at task completion in the digital environment  and a good deal of that extra time is taken up with navigation.
For all people the exploding quantity of information presents a serious problem but blind and visually impaired people are forced to plough through masses of report lines because they cannot scan and Internet page changes produce large quantities of repeat metadata which it is difficult to 'skip'. They also have problems with understanding the way that data choices are displayed, a disadvantage they share with many people who have learning, cognitive and developmental difficulties.
In the context of convergence, navigation might be facilitated through a much closer adherence to the (7 + or - 2) rule . By coincidence, the outer limit of this rule is nine which accounts for the 1-9 digits on a numeric keypad. Taxonomy by nine presents major commercial opportunities and offers a degree of usability and familiarity of approach  .
Closely related to navigation is the issue of evaluation, of assigning weight and significance to sources. A student does not want tabloid journalism on his subject but neither does the general reader want monographs. In other words, it is the relevance not the intrinsic merit of the information which is in question. Again, blind and visually impaired people and those with learning difficulties are most disadvantaged by being presented with massive search reports of undifferentiated information.
The answer for many of us is to learn how to define a search but a more satisfactory solution is the use of a system which adjusts to user behaviour over time which therefore allows the user to work deliberatively, as opposed to serendipitously. Such a system can 'learn' what the user is interested in and the professional level of that interest. This is by far the most important assistance that most disabled people can be given.
Another aspect of the learning process which ought to be considered carefully is the role of blended learning. The development of broadband telephony has greatly enhanced the possibilities of students and tutors sharing on-screen displays and discussing work in progress but these facilities are even more important for disabled people who tend to 'get stuck', sometimes thwarted by what to most people would be trivial barriers.
In conclusion, here is a short summary of what needs to be done to enhance accessibility and to break away from the traditional approach:
None of these proposed solutions are science fiction - they are all available now - but we must stop travelling into the future with our back to the engine; it is time to turn round and face the future.