3.3.4 - Error prevention (legal, financial, data)

Summary

When completion of a form causes a legal commitment, triggers a financial transaction, or gives consent for personal data to be updated, the user must be able to review, correct, and confirm that the information they have entered is correct, or they must be able to reverse the decision.

Requirements

• When data is submitted leading to a legal commitment, financial transaction, or an update to personal data, a review page is presented that allows the user to review, correct, and confirm the information they have entered.

Common mistakes

• An online shop where order details are not displayed again for confirmation just before users' commit the transaction.

Why?

This provides safeguards to prevent people with disabilities, and indeed all users, from making avoidable mistakes.

Official wording in the Web Content Accessibility Guidelines

3.3.4 Error Prevention (Legal, Financial, Data): For Web pages that cause legal commitments or financial transactions for the user to occur, that modify or delete user-controllable data in data storage systems, or that submit user test responses, at least one of the following is true: (Level AA)

• Reversible: Submissions are reversible.

• Checked: Data entered by the user is checked for input errors and the user is provided an opportunity to correct them.

• Confirmed: A mechanism is available for reviewing, confirming, and correcting information before finalizing the submission.

See the W3C's detailed explanation of this guideline with techniques and examples.

Guidance for Design

More guidance for design

• Design pattern: Let the user review and correct information before submission
• Design pattern: Requesting confirmation to continue with their selected action