How tables can make content less accessible
This article originates from a tweet I almost sent.
I’d been trying to find clear reasons explaining why tables are not an accessible way to present content, with the exception of data – and then only when the table is simply structured. The person I needed to convince wanted external proof, and a more detailed reason than “they can be difficult for screen reading software to navigate”.
My draft tweet:
“Does anyone have a link to a page explaining why tables are not an accessible way to present content, except data? Need evidence to show a stakeholder… Searched GDS service design manual and accessibility pages, W3 site, RNIB, Google… @a11ylondon #accessibility”
In the end, through a Google search University of Minnesota came up with the best explanation of why tables aren’t accessible. So many authoritative sites that I hold in high esteem advised against using them, unless for data, but no-one was saying why.
Your design’s great… but I think a table would be good
And when you tell a stakeholder, no you can’t have this thing that you think is a very good solution, and have been using forever, they tend to want to know why, with more detail than “it isn’t good for accessibility”, and that’s not unreasonable of them.
Keep it simple. Always.
The explanation came from University of Minnesota:
“Screen readers will read the content of a table in a linear fashion — left to right, top to bottom.”
“Complex tables that include nested tables or that require two rows in order to explain the information contained in the columns, are more difficult to tag for accessibility.”
Simple data tables can be easily navigated. They may not cause too much cognitive load. However, complex tables especially with nested elements, are more difficult to tag for accessibility, so should be avoided for data presentation unless the reading order is made logical for screen readers to follow.
Do not merge cells
“Tables should not contain merged cells as they are difficult to navigate with screen readers…”
Merged cells are difficult to navigate because they confuse the reading order.
Always avoid using tables for content layout
Always avoid tables as a lay out choice for textual content. The screen reader will read cells left to right, which may not be the correct content hierarchy. Screen reader users can choose to navigate page content by level 2 and 3 headings.
This was a great explanation to access, as the thing the stakeholder wanted to use the table for as a comparison chart for search results, of what detailed text descriptions of academic grant information and eligibility criteria. So, a lot of rows, sub-headers and complexity. Of course, there are various other reasons why this would not be the best way to design search results content!
My view on tables
My next points are a content designer’s perspective, mine, and is not from a university or accessibility authority. I have, however, led on and written up Content Design London’s collaborative Readability Guidelines.
Although tables can and should be labelled, textual tables limit user choice in how to navigate and absorb the content on a page. If, for example, I’m only interested in census data around 18 to 24-year-olds, I listen for the most relevant page sub-heading and jump straight to it. When this is in a table, I need to listen to the whole table and navigate through the rows. So I have to listen to, fast-forward through or skip rows with information on age categories 0 to 4, 5 to 9, 10 to 14, 15 to 17.
Is it ever an equal experience?
What’s more, consider that tables can’t be scanned diagonally, or from one row to another three rows down, skipping the middle ones, by people using screen readers in the same easy way that people looking directly at tables without a screen reader can.
So they may not be an equal way of presenting information for quick comparison for those users. Though they can speed up the screen reader speed, they can’t dot about the table, even a simple data table, with the same ease as users accessing tables visually.
As a content designer, I look for the best way to present information to users. I’m personally not convinced tables are the answer, ever. I may delve further and write a follow-up article on that. Clever questions may be the answer, or headed descriptive comparisons. As ever, formal, rigorous testing with users is the only way to find out for sure.
Screen reading software in action
Watch this video about good and bad table design, it’s narrated by a screen reader:
Here’s another:
Learn more
Find out more about accessible tables and making your website accessible:
The above article is an updated version of the original ( August 2018) to make it clearer that simple data tables can be accessible.
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