- From: Nick Kew <nick@webthing.com>
- Date: Tue, 19 Mar 2002 00:09:50 +0000 (GMT)
- To: <w3c-wai-ig@w3.org>
I've had a comment regarding the way Page Valet reports WCAG accessibility warnings. My correspondent[1] thinks it should mention any WCAG points that are untested, as this is how some other accessibility tools work and it makes Valet seems less complete[2]. As it stands, Page Valet will generate warnings when it detects an error (or potential error). When it applies a test that is passed it says nothing. When it doesn't apply a test, it says nothing. Now the suggestion is that is should - conceptually - test every point in the WCAG. In cases like #14.1/etc that self-evidently can't be tested by any tool, it should issue a nag message - whatever page is being tested. Now, I have several reasons not to apply this kind of completeness. But maybe I'm missing the wider view. Comments, please, on: * Nag messages are a turnoff. If more than a couple of messages are repeated in every evaluation, users will rapidly learn to ignore them. * If we say that Valet should exhaustively list every point in WCAG, are we not saying that WCAG itself is the best test tool - and the only one that is never wrong? * Valet applies tests to every element and attribute, and displays messages in place in the source code. This is designed to make it more useful to its users: "there is an error right here" as opposed to "there is an error somewhere" Listing tests per-document is an entirely different approach. * Because Valet applies per-element tests, there are tests that are both applied and not applied. For example, #4.1/#4.3 (the lang attribute) is tested for the <html> element[3], but not for other elements. Yet to be exhaustive, we should test *every* element, lest it contain a passage in another language. For the tool to be manageable at all, it needs to make compromises. * Bottom line: too many nag warnings will dilute the overall message of the tests - like useful content getting buried in waffle or (in our times) spam. Now, one possible solution here is to retain the present scheme (modulo updates) for the human-readable HTML reports, but to include the additional nag messages in the machine-readable EARL reports so they get into databases populated by Valet (such as W3C's Annotea). [1] She reads this list, so she'll doubtless reply if I'm misrepresenting her. [2] Section508 testing does take this more legalistic nagging approach. That works because 508 is much briefer, and expressed in terms that are easier to incorporate into an automatic tool than WCAG. [3] The lang attribute for html shouldn't be necessary at all in the presence of an HTTP Content-Language header. But testing for it seems to be a requirement for any WCAG testing tool. -- Nick Kew Site Valet - the mark of Quality on the Web. <URL:http://valet.webthing.com/>
Received on Monday, 18 March 2002 19:10:53 UTC