Impact on Users

The following is an overview of common table accessibility errors and the impact on users with a disability.

Data tables

Table headers are not coded
When a data table is not coded with TH,SUMMARY and CAPTION it can be difficult for a screen reader user to understand the meaning of the content.
Tables without a descriptive SUMMARY element or CAPTION attribute

When a table is presented without a CAPTION element the table does not have a title.

When a table is presented without a descriptive SUMMARY attribute the screen reader user does not get an overview of the content. This overview assists them in understanding the table.

Data tables are used incorrectly

Empty tables are often hidden from the sighted user but they are still interpreted by assistive technology. Empty tables can mislead and confuse the screen reader user as they contain no content and serve no purpose.

Data tables with empty rows can also confuse the screen reader user. They cannot visually see the meaning, if there is one, implied by the use of the empty row. The table structure should be simplified to remove the need for an empty row.

Avoid excessive nesting of tables which may be incorrectly interpreted by a screen reader user.

Data table content is legible
When content does not meet colour contrast requirements or if information within a data table is conveyed using colour, shape or shading alone the meaning of that information may be lost to those with visual or cognitive disabilities.
Additional information is not provided for complex data tables
When complex tables are provided without sufficient explanatory information within the page content, the understanding of the table data may be difficult or impossible to understand. Supplementary or supporting information for complex tables benefits all users but particularly those with cognitive disabilities.

Layout tables

Layout tables are coded as a data table
If a layout table is coded with TH, SUMMARY attribute or CAPTION elements it will be interpreted incorrectly by the screen reader user as a data table.
Layout tables are used incorrectly
When mathematical equations are presented using a layout table in preference to MathML, the user may not understand the formula.
Layout tables are not meaningful
If layout tables do not have meaningful sequence then the screen reader user may not be able to understand the content.