[Bug 22791] New: Alt text for charts, graphs etc should (when sensible) state what the graphic is

https://www.w3.org/Bugs/Public/show_bug.cgi?id=22791

            Bug ID: 22791
           Summary: Alt text for charts, graphs etc should (when sensible)
                    state what the graphic is
    Classification: Unclassified
           Product: HTML WG
           Version: unspecified
          Hardware: PC
                OS: Linux
            Status: NEW
          Severity: minor
          Priority: P2
         Component: HTML5 spec
          Assignee: dave.null@w3.org
          Reporter: stommepoes@stommepoes.nl
        QA Contact: public-html-bugzilla@w3.org
                CC: mike@w3.org, public-html-admin@w3.org,
                    public-html-wg-issue-tracking@w3.org

In
http://www.w3.org/html/wg/drafts/html/master/embedded-content-0.html#graphical-representations:-charts,-diagrams,-graphs,-maps,-illustrations
there are examples of different kinds of images. The recommended alt text for
pie charts clearly state "Pie chart" but none of the other image types state
their type.

The results of the first and second WebAIM screen reader user studies (2008,
2009) showed a preference among survey takers for alt text to mention what kind
of graphic it refers to [1] [2], possibly because the alt text in those
particular questions already lack context. That's not to say everyone always
wants graphics labeled, but that context of a graphic likely matters to many
relying on alt text.

This makes sense for context reasons: say students are discussing a page in an
online textbook containing 2 bar graphs and 1 pie chart, all showing different
aspects of the same subject. With the context of what kind of graphic
available, the students can more easily refer to the graphics by type, or
search by type. Not only is the information in the graphic conveyed visually,
but also what kind of graphic it is as well.

As the WebAIM studies caution, this doesn't mean every graphic should be
labeled this way, but on a page containing multiple complex graphics I feel it
should be recommended.


[1] http://webaim.org/projects/screenreadersurvey/#images
[2] http://webaim.org/projects/screenreadersurvey2/#images

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Received on Wednesday, 24 July 2013 06:45:11 UTC