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Comment on Equivalents (including relevance to deaf nonreaders)

From: eric hansen <ehansen@ets.org>
Date: Thu, 11 Mar 1999 13:36:52 -0500 (EST)
To: w3c-wai-gl@w3.org
Message-id: <vines.yRv7+2y+uqA@cips06.ets.org>
I think that the terms "text equivalent" and "video equivalent" need to be 
clarified. 

The term "text equivalent" is not defined initially and its contrast to 
"long description" is unclear. See, for example, the explanation of 
Guideline 2: "A long description, unlike a text equivalent, describes the 
visual information presented by an image, script, or applet." This seems to 
contradict the idea that a long description is a kind of text equivalent. 

I suggest the following definitions that might be placed either in the 
glossary or the techniques document.

1. An "equivalent" provides essentially equal functionality for users who, 
because of disability, technological constraints, or other circumstances, 
cannot or choose not to access the functionality in a more conventional 
way. {EH: Note reference to "essentially equal functionality". It may not 
be totally equal.}

2. A "text equivalent" is an equivalent in which the functionality is 
expressed in text that is available for speech visual, braille, or speech 
output. Text equivalents may be implemented in many ways, e.g., as 
alternative text, long descriptions, d-link descriptions, captions, titles, 
or, in some circumstances, as portions of the main body of a document {EH: 
I feel the that the last phrase must be correct, though I am at a loss at 
the moment for a good example}. Short text equivalents are often 
implemented as alternative text. Longer text equivalents are often 
implemented as long descriptions and d-link descriptions.

3. A "nontext equivalent" is an equivalent not in the form of text {EH: Is 
this accurate?} Examples of nontext equivalents include graphical, video, 
prerecorded audio equivalents. An example of a video equivalents would be 
videos of sign language renderings of the content. [etc., etc.] {EH: By the 
way, nontext equivalents are particularly important for deaf nonreaders.}

=============================
Eric G. Hansen, Ph.D.
Development Scientist
Educational Testing Service
ETS 12-R
Rosedale Road
Princeton, NJ 08541
(W) 609-734-5615
(Fax) 609-734-1090
E-mail: ehansen@ets.org 
Received on Thursday, 11 March 1999 13:41:23 GMT

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