Users of screen readers cannot interpret tables the same way sighted users do. Sighted users can tell at a glance what column and row a given cell is associated with, but a screen reader user needs a properly coded table. To make tables usable, additional steps will need to be taken to make them accessible.
Examples of tables: simple table.
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The image above displays a simple table: books read by two people. Only column headers are needed to identify who read which books.
Examples of Tables: Complex Table
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In the image above, there is a complex table: books read by two people each week. Both column and row headers are needed. In this, a screen reader user will know that The Sound and the Fury was the book read by Tomiko on Week 3.
Steps to make tables accessible.
Designate headers.
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When adding tables in the Rich Text Editor, add a row and/or column to be used as a heading for each as appropriate. The table creation menu contains a Headers dropdown menu that allows for designating the first row, column, or both as headers.
Add a caption.
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Add a Caption, if necessary, to the table to inform readers of the table's content. Good examples are "Data from recent study," "Table of inputs and outputs," etc.
Tip: Tables should only be used for tabular data, not for layout.