When is user error prevention required?

Under the Web Content Accessibility Guidelines (WCAG), requirements for error prevention depend on the level of conformance you are trying to achieve and the type of user information involved.

It is a WCAG 2.1 AAA requirement to always include an error prevention mechanism when users are submitting information. Error prevention is helpful for everyone, so it's a good idea to implement this guideline even if you're not aiming for full AAA conformance.

For WCAG 2.1 AA conformance, error prevention is required for only the following types of information submissions, per Success Criterion 3.3.4: Error Prevention (Legal, Financial, Data):

• “legal commitments”
• “financial transactions”
• “user-controllable data in data storage systems”
• “user test responses”

There are multiple error prevention techniques to choose from to meet this criterion. Common examples include an option to reverse or undo the submission, a step to review and confirm the submission, or automated checks for errors as the user creates the submission.

Once you’ve implemented an error prevention technique, the best way to check that it’s working well is to conduct accessibility testing with people with disabilities. Contact Accessible Web to learn more about this process!