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EARL Guideline Pass/Fail Confidence

From: Chris Ridpath <chris.ridpath@utoronto.ca>
Date: Thu, 15 Jan 2004 10:49:26 -0500
Message-ID: <083101c3db7f$275f9190$b040968e@WILDDOG>
To: "WAI ER IG List" <w3c-wai-er-ig@w3.org>

Charles has an example of EARL that shows how to express that a page
passes/fails an accessibility guideline. It's listed in his Coding EARL (for
non experts) document at:
http://www.w3.org/2001/sw/Europe/talks/200311-earl/all.htm

The EARL code looks like:

  <earl:Assertion>
    <earl:subject rdf:resource="#http://www.w3.org/" />
    <earl:result
rdf:resource="http://www.w3.org/WAI/ER/EARL/nmg-strawman#Pass"/>
    <earl:testcase
rdf:resource="http://example.org/1999/xhtml#transitional"/>
    <earl:assertedBy rdf:resource="http://validator.w3.org" />
    <earl:mode
rdf:resource="http://www.w3.org/WAI/ER/EARL/nmg-strawman#automatic"/>
    <earl:message>This page is valid XHTML</earl:message>
  </earl:Assertion>

Would this be a better assertion if there was an added 'confidence'
statement? Example:

<earl:confidence
rdf:resource="http://www.w3.org/WAI/ER/EARL/nmg-strawman#high" />
or
<earl:confidence rdf:resource=http://www.w3.org/WAI/ER/EARL/nmg-strawman#low
/>

An automated checker tool can only detect some problems, not all. It's up to
a person to determine if the page passes all accessibility checks. For
example, only a person can determine if an image does/doesn't require a long
description.

If the EARL expressed that the guideline was passed with a 'high' confidence
then it would mean that all accessibility checks had passed - machine and
human. If the confidence was 'low' then it would mean that only checks that
are machine testable had passed - one or more checks that require human
intervention had not passed.

Using the confidence statement an automated checking tool could tell the
user that "likely the page will pass but you still need a human to make some
accessibility checks".

Chris
Received on Thursday, 15 January 2004 11:04:02 UTC

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