Screen readers skip blank cells, which changes the order and association of subsequent cells. This can make it hard to tell which column heading a cell falls under. Make sure none of the cells in your table are blank:

• Include column headings for all columns, even if it seems obvious to you or the heading is generic, such as Item or Characteristic. This provides a heading for a screen reader to associate with all the cells below, making it easier for users of assistive technology to navigate the table.

• Use na for ‘not applicable’ and nd for ‘no data’. (Define these abbreviations as notes under the table.) Use 0 for a zero result. Do not use an en dash (–) for ‘not applicable’, ‘not available’ or a zero result, because assistive technologies may not be able to interpret it.