Tables are a useful way to list and compare data, and are particularly common in scientific and government content.
But what do you do when you have no data for a particular cell in a table?
In the past, it was acceptable to leave the cell blank, or to insert a dash. But – as well as providing little information for audiences – this practice now runs afoul of accessibility requirements.
Making your content accessible means that it can be read by a screen reader. If you leave a cell blank, the screen reader will skip it. If you add a dash, the reader will say ‘dash’, which might be confusing for the person listening.
Australian accessibility guides generally recommend against using a dash, but they don’t prescribe what should be used. So we did a bit of research to see what would be most accurate and understandable for audiences using a screen reader.
We found that the best recommendation is to be as accurate as possible:
- If the value is zero, put 0 rather than leaving the cell blank.
- If you don’t know what the value is, put ‘no data’ or ‘nd’.
- If the cell shouldn’t have a value because the headings aren’t relevant, put ‘not applicable’ or ‘na’.
Some people use ‘na’ to mean ‘not available’, but it’s a good idea to use ‘nd’ instead, so that it’s not confused with ‘not applicable’.
Using these basic rules will help to make your tables as clear as possible to all audiences.