- From: Charles McCathieNevile <charles@w3.org>
- Date: Mon, 14 Aug 2000 21:53:27 -0400 (EDT)
- To: Jason White <jasonw@ariel.ucs.unimelb.edu.au>
- cc: Web Content Accessibility Guidelines <w3c-wai-gl@w3.org>
I still have a strong preferences for maintaing the terminology of WCAG 1, for the following reasons.. The Guidelines specify general principles of accessibility, in a way that is independent (more or less) of any particular technology. The Checkpoints are the actual requirements for accessibility, although still expressed in a way which does not presume a particular technology. These can be verified, although doing so requires knowledge of how the requirement may be met by using the technology in question each time. The techniques, however, provide specific ways of meeting the requirements for specific technologies. As Kynn used to ask, we need to be clear about whether a given technique meets the entirety of the requirement or not in some cases it will others not. For example, alt attributes cannot by themselves fulfill the requirements of WCAG 1 checkpoint 1.1 except in a limited, albeit large, set of cases. Otherwise we are still at the level of fundamentally approaching this from a particular technology, and then trying to add others as we figure them out. The approach outline is the approach taken by ATAG, which when combined with its current dependency on WCAG 1 for a quarter of the requirements means that testing an individual piece of software for conformance is a lot of work. On the other hand, it has given us a set of guidelines that is as useful for image and multimedia editing software as it is for HTML software (insofar as the WCAG can be appropriately applied to those areas). And it means we don't have to change terminology on people - if we are going to shift the meanings then we should simply use completely different words, and I do not think that is justified. Charles McCN On Tue, 15 Aug 2000, Jason White wrote: There is a problem of terminology which needs to be resolved. In WCAG 1.0 the most abstract and general requirements were called "guidelines". The more specific requirements were termed "checkpoints". In working group discussions subsequent to the publication of the WCAG 1.0 Recommendation, it was decided to develop a three-layered hierarchy of requirements. The first two layers were to be framed in terms that did not invoke the capabilities or limitations of particular, existing standards or technologies. The third layer, however, was intended to offer concrete and, so far as possible, readily verifiable implementation requirements, specific to particular standards or technologies (for example, HTML/CSS, XML, SVG, Smil, the DOM etc.). In working group deliberations surrounding these proposals, there emerged a tendency to speak of "technology-specific checkpoints". This led to a confusion of nomenclature, in that the term "checkpoint" thus became ambiguous, in so far as it could apply either to the second or the third layer of the three-tiered construction outlined above. This lack of clarity has been facilitated by the text of WCAG 1.0, in which some of the checkpoints are expressed in relatively general terms, whereas others are quite specific to existing standards and technologies, most notably HTML. Accordingly, in WCAG 2.0 it will be necessary to clarify the important concepts around which the requirements are structured and to use terminology in a consistent fashion. Inevitably, this will result, to some extent, in a departure from the usage conventions adopted in WCAG 1.0, as there are now three, rather than two, fundamental divisions along the continuum from generality to specificity, from the abstract to the concrete. Proposals currently on offer: 1. To use the terms "principle", "guideline" and "checkpoint" as defined in the current draft, thereby making an explicit departure from WCAG 1.0. 2. To use the terms "guideline", "checkpoint" and "technique" to designate the three levels (proposed by Charles). This has strong historical roots in the early days of the guidelines. However, "techniques" (as in the "techniques document") have since come to be regarded not as numbered, verifiable requirements, but as implementation strategies which are explained and exemplified in the Techniques document. Furthermore, given that the technology-specific requirements constitute the level at which (manual or automated) testing is to be performed, it would seem counter-intuitive to regard the second of the three layers (which is not technology-specific) as checkpoints, a term which implies that these are the criteria against which to verify compliance, whereas the more verifiable (testable) requirements are to be called "techniques". 3. To refer to the three levels, respectively, as "principles", "strategies" and "checkpoints" (proposed by Gregg). By designating the second layer as "strategies", it would be implied that not all of these requirements need be fulfilled in order for content to be accessible, but that certain combinations of requirements under each principle need to be met for purposes of compliance. Again (as I understand it) the checkpoints, being technology-specific, would provide the basis for testing, with satisfaction of certain combinations of (technology-specific) checkpoints having been deemed to constitute application of the strategies which in turn satisfy the requirements of the principles of accessible design. In conclusion, I would argue that none of the terminological options is entirely satisfactory, all involve some departures from past practices, and that precise definitions need to be established so they can be applied consistently in future drafts of WCAG 2.0. Note: the foregoing summary is intended to outline the relevant arguments and not to indicate any preference, on my part, for one solution over another. Specifically, I think they all have advantages and drawbacks, but that a clear decision needs to be made by the working group. -- -- Charles McCathieNevile mailto:charles@w3.org phone: +61 (0) 409 134 136 W3C Web Accessibility Initiative http://www.w3.org/WAI Location: I-cubed, 110 Victoria Street, Carlton VIC 3053 Postal: GPO Box 2476V, Melbourne 3001, Australia
Received on Monday, 14 August 2000 21:53:35 UTC