Estimated reading time: ( words)
Summary: Accessible tables are simple, rather than complex, have an identified header row, and include a table summary, either as a caption or as alt text. These techniques help screen reader users read the information contained in the table.
This article helps you understand the difference between the two types of tables, as well as the general principles of accessible tables. In general, you should use tables to display data rather than as a way to make your document or webpage look the way you want it to.
Layout tables are used to position elements in a document. Layout tables do not represent or imply any relationships among content.
Screen readers will read the content of a table in a linear fashion — left to right, top to bottom. Verify reading order by tabbing through the tables and confirming the progression is logical. An example, courtesy of webaim.org, here’s an example of a table used for layout:
Here is the same table with numbers that show you the order in which a screen reader reads the table. How much sense does it make to you?
Be thoughtful about using tables for layout in your documents – they could make your document more confusing for some people.
While these tables can be hidden from visual users by simply eliminating the borders between cells, they cannot be hidden from screen readers in MS Word. This prevents users with low vision and learning disabilities from attempting to understand the information presented.
Data tables are grids that show the relationship between two or more items, in rows and columns. Use simple tables wherever possible. 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. Consider this example:
Noble gases and their atomic numbers
|Noble Gas||Atomic Number|
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.
Screen readers read the content of a table left to right, top to bottom, and they should have no problem reading the content of this table as long as the header row has been identified (see below).
Complex tables, on the other hand, are created any time you have tables nested within tables; when cells are unpredictably merged, or when data requires more than one row to make sense of the content.
It is recommended NOT to use tables nested within tables or tables with randomly merged cells. However, you can still use a complex table in your document if the reading order of the table is logical. You can verify the reading order by tabbing through the table cells.
Data versus layout tables
Tables should not contain merged cells as they are difficult to navigate with screen readers.