Error messages are actually useful, e.g. provide a useful next step or way of entering valid data

If an input error is automatically detected, suggestions to recitfy the issue are provided to the user.

Design and Developer Notes

Ensure error messages are useful

When someone makes an error while filling in a form, provide suggestions on how to correct it.

When an error is automatically detected, provide suggestions for how to recover – unless doing that would compromise security (like giving password hints, for example).

Complementing text with icons can also help users quickly scanning forms and those with cognitive or learning difficulties.

Appropriate error suggestions include:

• Indicating a required field has been left blank
• Indicating the required format for the field in error
• Indicating a range of valid values for the field in error

Related

• https://design-system.service.gov.uk/components/error-message/ — From the 'Clear and concise' heading onwards, in particular

Testing Notes

Error messages are actually useful, e.g. provide a useful next step or way of entering valid data

If an input error is automatically detected and suggestions for correction are known, then the suggestions are provided to the user, unless it would jeopardise the security or purpose of the content

For example: An input field requires that a month name be entered. If the user enters "12," suggestions for correction may be a description of the set of values, e.g.:

"Please provide the name of the month." The conversion of the input data interpreted as a different month format, e.g., "Do you mean 'December'?"

Steps to check

• Open page with a form
• Intentionally leave all fields blank and submit
• Check content of resulting error messages

Impact range: Medium

Test type: Manual

WCAG Reference: Understanding Success Criterion 3.3.3 Error suggestion