Re: Table summary: technique for writing

Hi Chris,
1. Chris: Our techniques [1] state that the summary should describe the *purpose* and structure of the table. Your document suggests the summary should describe the *contents* and structure of the table.

  Does our technique cover what you're suggesting?
  Sailesh:I maintain that every data-table should have a caption that conveys the purpose of the table like a title. But I understand that the caption is visual and the WG regarded it as unenforceable. So if the caption is absent, the summary might be the place to convey the table's purpose. 
  A sighted user is able to identify and read the cells   that contain the key  contents in a table like totals / averages / percentages etc. Conveying this through the summary if it is not in the surrounding text will help a non-visual user grasp the highlights.  

  2. Chris: The technique also states that the summary is optional on data tables. Are there conditions under which the summary is mandatory?
  Sailesh: I believe complex or Layered and irregular tables   should always have summaries. 
  The summary should chiefly convey the layout / structure of such tables. 
  The purpose and content are optional and would not be required if conveyed through the caption or in the surrounding text.
  Simple tables:
  One might argue that the purpose and key content are relevant for  simple tables as well. Again,they would be optional as stated above. Simple tables are more easily navigable and  one can run through the content    quickly. The size of the table  too is a factor to be considered. Consider describing the contents for a simple table if it has more than 5 columns and 10 rows (no scientific basis for these numbers), and if contents are not described elsewhere.
  Whether contents should be described depends on the nature of the data in the simple table. If the table lists states and their attributes like its capital, governor, etc. it may not require a summary. A user just needs to navigate to the    row of interest and read the data.
  3. The techniques doc should not suggest that   it is ok to use caption or summary and that it is rare to use both. 
  The examples in the tech doc are good. 
  Thanks for posing these questions. I was too focussed on  the structure aspect.

  [1] http://www.w3.org/TR/WCAG20-HTML-TECHS/#datatables_summary

  Sailesh Panchang
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