- From: Jason White <jasonw@ariel.ucs.unimelb.edu.au>
- Date: Sun, 7 Jan 2001 15:02:13 +1100 (EST)
- To: Web Content Accessibility Guidelines <w3c-wai-gl@w3.org>
My response to Wendy's proposal is somewhat complex and cannot be stated within the terms of the provided questionnaire, which, with regret, I must therefore decline to answer directly. Before proceeding to give a substantive discussion of the issues, I should emphasize, from the beginning, that Wendy's analysis is revealing, thought-provoking, and most welcome. My primary concern is that the categorizations, notably in guidelines 1 and 2, are somewhat arbitrary and that the checkpoints do not fit neatly under the guidelines (except those of guideline 3, which are somewhat better in this respect). Of course, there is substantial scope for legitimate disagreement as to what division of the subject into basic, general propositions best captures the essential constituents of universal or accessible design, and can be most effectively employed as a conceptual aid to the understanding and application of the more detailed requirements which are subsumed under these broad statements. As has been remarked on enumerable occasions, we need to arrive at a balance between generality in the formulation of the high-level guidelines, and concreteness in specifying, albeit still in quite broad terms, what, conceptually, are the elements of accessible design, of which the document as a whole is, fundamentally, an elaboration. With these qualifications in mind, I shall venture to advance an opinion, for what it is worth, regarding the specifics of this proposal. Guideline 1: The concept of "graceful transformation" is here extended well beyond its conventional meaning. The principal argument for retaining the term "graceful transformation" was that it had a well understood technical meaning, as evinced by WCAG 1.0, according to which it referred to the capacity of content to remain usable across a diverse range of older and newer software (particularly user agent) implementations. In the current proposal it is broadened to such a degree as to become a "catch-all" concept that encompasses a multiplicity of disparate requirements, the logical connections among which are far from obvious. These include modality-independence (text equivalents and their concomitant synchronization requirements), compatibility with user agents, including older technologies; and the use of style languages to control layout and presentation. The second of these covers what has traditionally been meant by "graceful transformation", and I find it hard to discern any clear reason for connecting it, under a single heading, with either text equivalents or style languages. One could of course extend the term "graceful transformation" to include the other two concepts, but if one were to do so, then why should one not go further and declare that device-independence (which is what style sheets are, in part, intended to achieve) is really part of the concept of graceful transformation, and that everything subsumed under the proposed guideline 2 should actually be brought within guideline 1? Stated differently, one can either limit the concept of "graceful transofrmation" to its conventionally understood meaning, or broaden it, in which case I do not see any non-arbitrary reason why it should refer only to interoperability and compatibility, text equivalents/modality-independence, and style languages (separation of content and structure from presentation). Guideline 2: In effect, the same remarks apply here as well: the concept of "device independence" is entirely capable of embracing most of the checkpoints under guideline 1, as well as those which have been proposed as guideline 2. Thus, within the class of possible output devices, there are those which happen to be auditory, others which are visual, and still others which are tactile. Within each of these categories there are further subdivisions (small and large screens, high and low-resolution displays, printers, braille embossers, dynamic braille displays, and various kinds of speech synthesizer). It seems somewhat arbitrary to separate out modality-independence, placing it under the heading of "graceful transformation", along with the use of style languages, whereas the proper representation of structure and semantics, and a range of further requirements connected with navigation, distracting or time-sensitive content, etc., are collected under the rubric of device-independence. In fact, as Lisa has pointed out, the issue of time-sensitive and distracting content is at least as much of a cognitive matter as it is a question of device-independence, and thus it fits uneasily at best into the latter category. More importantly, as I have already intimated, one can regard modality-independence and style languages as matters of device-independence, thereby collapsing most of guideline 1 into guideline 2, with user agent compatibility and interoperability being the only requirements under guideline 1 that arguably wouldn't fit (unless one decides somewhat arbitrarily that each user agent should be treated as a separate "device", in which case the whole of guideline 1 becomes part of guideline 2). Thus, the upshot of my analysis is, first, that the general concepts of "graceful transformation" and "device independence", as used here, threaten to collapse into one another. If the concept of "graceful transformation" is extended, as proposed, then the distinction between it and device-independence becomes arbitrary. One could just as easily use either concept as a guideline under which to place many of the checkpoints proposed for guidelines 1 and 2. As I have also argued, some of the requirements, especially the avoidance of distracting content, movement etc., are a matter of cognition rather than graceful transformation or device-independence. One could extent the proposed guideline 3 to include these phenomena (ensure that content is easy to comprehend, and that it does not distract or interfere with the reader's ability to navigate, for example). Next, one could broaden the notion of device-independence, or of graceful transformation, to cover most of the other checkpoints. The result would be highly general but, in my opinion at least, hardly insightful, and certainly it would not be easy to remember as a basic set of underlying requirements. Nor is Wendy's proposal satisfactory, for the reasons which I have indicated, and I would not wish it to form the basis of the next draft. What is needed, rather, is a scheme in which the checkpoints fit logically under the guidelines, in which there is a clear connection between the basic principles and the more specific requirements subsumed thereunder. Of course, it might be maintained that any division into guidelines and checkpoints will inevitably be, to some extent, arbitrary. This is probably true, but some possible divisions are obviously better than others. I would have liked to present here an alternative scheme, but I need to give the matter further thought. I think the existing set of five guidelines (from the latest draft) is quite good: (1) modality-independence; (2) separation of content and structure from presentation, together with proper exposure of semantics; (3) facilitation of comprehension; (4) facilitation of browsing and navigation; and (5) device-independent handling of user input. One could perhaps argue for: (1) device-independence, covering text equivalents, separation of content and structure from presentation, and exposure of structure and semantics; (2) browsing and navigation, covering site maps, linking, summaries, search facilities etc.; (3) comprehension and cognition, encompassing Wendy's proposed guideline 3 as well as the avoidance of distracting content, blinking/flickering content etc., given their perceptually-based rationale; and (4) compatibility and interoperability, covering standard-compliance and compatibility with older technologies.
Received on Saturday, 6 January 2001 23:02:17 UTC