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Re: Nested data tables

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From: Steve Green
Date: Oct 20, 2020 4:07PM


My experience is that screen readers have no problem with nested tables, but screen reader users do. Even things like rowspans can cause difficulty. In more than 15 years of user testing, I don't recall seeing any screen reader user use the table navigation commands - they all "arrow" through the table, hoping that the data in each cell gives a clue as to what the column heading is. In small tables, they might remember all the column headings and keep track of where they are by counting the cells.

I doubt if 90% of users even know that there are table navigation commands. Remember that the screen reader users in this forum are probably in the top 1%, so their ability is unrepresentative of users in general.

I'm not saying that you should not use complex tables, but the only way to know for sure is to do user testing with people of average ability. And 50% of people are below average, so you ought to include some of them too.

Steve Green
Managing Director
Test Partners Ltd


-----Original Message-----
From: WebAIM-Forum < <EMAIL REMOVED> > On Behalf Of Alan Zaitchik
Sent: 20 October 2020 21:54
To: WebAIM Discussion List < <EMAIL REMOVED> >
Subject: [WebAIM] Nested data tables

I understand that nesting a data table inside another data table is generally frowned upon, but in some cases it seems to me that nesting a table in another is exactly the best way to communicate the data relationships. I wrote a codepen which illustrates a case I am dealing with:
https://codepen.io/azaitchik/pen/QJXRQVQ. (The top row nests an inner data table.) Voiceover, Jaws, nvda all have no problem with the nested table, and I am wondering if there are guidelines as to when the tables (outer and inner) are “simple enough” that there’s no problem with nesting.
Any guidance people can offer will be most appreciated!
Thank you.
Alan