Table summary attribute and duplication?

[Leif K-Brooks]

For accessibility purposes, I've been describing all of my pages' tables
in their "summary" attribute". But what's the best thing to when the
table is also described in the page's content directly before it? For
instance, what should be the table's summary attribute in this example:

<p>The following table lists various food dishes I enjoy. Column "foo"
describes the level of Footonium present in the dish, whereas column
"bar" explains which drinks go well with it.</p>
<table>
....
</table>

 

[Toby Inkster]

<p>The following table lists various food dishes I enjoy. Column "foo"
describes the level of Footonium present in the dish, whereas column
"bar" explains which drinks go well with it.</p>
<table>
...
</table>

<p>The following table lists various food dishes I enjoy. Column "foo"
describes the level of Footonium present in the dish, whereas column
"bar" explains which drinks go well with it.</p>
<table summary="The format of table is described in the previous
paragraph.">...
</table>

 

[Karl Core]

<p>The following table lists various food dishes I enjoy. Column "foo"
describes the level of Footonium present in the dish, whereas column
"bar" explains which drinks go well with it.</p>
<table summary="The format of table is described in the previous
paragraph.">..
</table>

How is that at all helpful to a person using a screen reader (the intended
audience for table summaries)?
If anything, it is superfluous and a barrier to the actual content which it
describes. The table summary needs to be used for information that will
help the user understand the table's content. If that information was given
in the paragraph above the table, then no summary is needed, IMO.

 

[Jukka K. Korpela]

How is that at all helpful to a person using a screen reader (the
intended audience for table summaries)?

I guess it is meant to please "validators" and "guidelines".

The table summary needs to be used for
information that will help the user understand the table's content.
If that information was given in the paragraph above the table,
then no summary is needed, IMO.

That's how things are to real people, but accessibility guidelines and
checkers may still require that _every_ table must have a summary
attribute. They carefully obscure the question what the author should
do with layout tables. (summary=""? summary="layout table"? summary=
"A two-cell table, with navigation in the first cell, content
in the second cell"? - is is a structural table then?)

My idea (or the only idea that makes sense for me) about the summary
attribute is this: For tabulated data, the author should sufficiently
explain their purpose, idea, and structure before the table and in the
table caption and header part. This helps _everyone_. What it really
means depends on the table, its purpose, etc. But in _some_ situations,
the table has some features that are very obvious to a person who sees
the entire table, not otherwise. Instead of explaining such things
explicitly in normal content, we might use an attribute that is
specifically meant to be made available to the user when using the page
in other ways (i.e. so that the table is not seen in a typical way but
e.g. viewed in a one-line or otherwise small window, or listened to, or
accessed via Braille). Assuming summary is such an attribute, we could
write e.g.
summary="The rows are in ascending order by total income"
or
summary="The table shows only every 5th year of the statistics,
from 1900 to 2000."