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R: Selecting Web Accessibility Evaluation Tools

From: Roberto Castaldo <r.castaldo@iol.it>
Date: Thu, 27 Jan 2005 09:10:14 +0100
Message-ID: <41D18D940057BF7B@ms005msg.mail.fw> (added by postmaster@ms005msg.fastwebnet.it)
To: "'EOWG'" <w3c-wai-eo@w3.org>

Hi group, 

-Automated evaluation: 
Certain accessibility barriers can be   detected in an automated fashion
across a site efficiently using a tool. The results are very reliable
because the criteria for evaluation are specific and objective. Form control
has no label associated explicitly  checkpoint (12.4) or deprecated tags are
used like <u> (11.2 or images or area element have null or blank alt (1.1).
Absence of title for a page or frame is another instance that can be
auto-detected. So there are several barriers that can be reliably detected
in an automated fashion. 

I agree, but only if we're talking about using deprecated tags and other few
really automatic evaluations a tool can provide; but let's make attention
not to give a wrong message: even this kind (or any other kind) of
automation cannot replace the intervention of a skilled human developer, and
this must be clearly said in our document if we decide to speak about
automated evaluation. 

-Automated repair: 
Some repair techniques can be  implemented in an automated fashion
accurately and reliably. Adding keyboard equivalent events like onFocus and
onBlur for onMouseover and onMouseOut is an example. 
Yes certain barriers can be detected with user interaction and certain
barriers can be fixed  using user input.

Does really an automatic repair tool exist? I don't think so. I can see that
some limited kind of automatic problem detection software exists, but then,
when a developer has to fix the problem, he cannot count on any
algorithm-only based. 

Consider, once an alt text is given for an image, an automated tool can
create an alt-text repository and use that alt-textfor all occurrences   of
the img on the page or site. Example: there is a img of a pdf icon next to
every PDF file on the site and it has a null alt. The user enters "PDF
Acrobat File" as alt-text and the tool assigns it across the site. Would one
characterize this as almost entirely automatic or as semi automatic?
True  it cannot judge if the alt-text is appropriarte.

I think this is a semi-automatic one; if a single page contains several
images of different PDF files, the procedure above fails, as it gives the
same alt-text to different images; i'm trying to say - as Sailesh himself
says - that developers must discuss about any alt-text in any page; no tool
can correctly perceive context. So, if we consider it as an automatic task
we risk to give a completely wrong message.

A tool can have a rudimentary  algorithm for detecting data tables and might
again ask the user for confirmation. Once it is confirmed as a data table,
the tool can ppoint out that it has no markup for associating header and
data cells.

Once again the tool can only detect a data table, but the developer has to
understand the problem and give his own solution. The software tool can
guide developers (and i'm not sure it's always a good thing), but cannot
complete the repair task on its own. So, once again, we're talking about
semi-automated repair tools.

So I think it is unfair to  not even recognize the presence of automated
tools for eval and repair.
The only reasons certain barriers cannot be identified in  an automated
fashion is because there is no objective criteria for detecting  these. 

We could consider to add a sentence or a small section dedicated to
automatic evaluation (not repair) tools, and this can be useful to make the
document more complete: a not skilled developer reading our document may ask
himself: "what about automated evaluation and repair? Why this document
doesn't talk about them?". If so, this section should stronlgy warn the user
that automated tools can only give some suggestions, and cannot complete any
task in repairing a not accessibile web page.

My best regards,

Roberto Castaldo
Webaccessibile.Org coordinator
IWA/HWG Member
Received on Thursday, 27 January 2005 08:10:49 UTC

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