Thank you for the concise answer, David.

I believe that screen readers and talking browsers do more than interpret
table attributes. It would appear that JAWS -- I don't know about other screen
readers -- uses an algorithm to extract possible row and column header
information, even when headers are not specified. The algorithm works
remarkably well for simple data tables. I have been producing and testing
tables that do not use TH or SCOPE, and JAWS has read them all correctly.
(Thank you again David, for your mini-tutorial on JAWS's table-reading
hotkeys). I am sure that there are limits to what can be accomplished
algorithmically, and I will be testing increasingly complex tables during the
coming days. My goal is to determine the minimum mark-up to ensure that data
tables of differing complexity are screen reader accessible. (I will share my
results with the group.)

Does anyone know which table attributes Window-Eyes and Home Page Reader look
for?

> Here's the info I recieved from freedom scientific.
>
> JAWS supports the following attributes for specifying row/column headers:
>
> scope
> Headers and ID
> Axis
> ABBR - when used with Headers and ID, but not with Scope
>
> However, the information specified in these attributes is only read when
> navigating with the table specific commands ALT+CTRL+arrow keys or
> ALT+CTRL+NUM PAD 5. And JAWS only reads the info as it changes. For example,
> JAWS reads row headers as you move down a column and column headers as you
> move across a row.
>
> Does Jaws 4.5 interpret the scope attribute in data tables? I cannot make it
> work. If it can be made to work, the problem of access to simple date tables
> would disappear, or at least, become much less serious... provided content
> providers would mark up their tables correctly!!
>
> The th element works nicely, and Jaws does a good job of reading tables when
> the header applies to every cell in a column. But what if it is necessary to
> associate cells with column header AND row header information?
>