Understanding WCAG SC 3.3.4 Error Prevention (Legal, Financial, Data)
Version and Level: 2.0/2.1/2.2 (Level AA)

Success Criterion 3.3.4 Error Prevention (Legal, Financial, Data) requires that web pages involving legal commitments, financial transactions, submission of a test or the modification/deletion of user data provide mechanisms to prevent errors. This ensures users have the opportunity to either review, correct, or confirm their input before finalizing actions.

Benefits:

  1. Error Reduction: Reduces the risk of users making mistakes in critical data submissions. Increased Confidence: Users feel more confident in submitting information knowing they can review and correct errors.
  2. Increased Confidence: Users feel more confident in submitting information knowing they can review and correct errors.
  3. Enhanced User Experience: Provides a smoother and less stressful experience, especially in high-stakes interactions.

Main Objective:

To prevent errors in legal, financial, and data-modifying transactions, as well as during tests, mechanisms should be provided for users to review, correct, and confirm their inputs. In many cases, when users opt to complete specific tasks, the result of incorrect completion could lead to significant mistakes. For instance, purchasing stocks and accidentally entering an incorrect amount (e.g., entering 10,000 instead of 1,000). The objective is to minimize such situations as much as possible.

When legal, financial, or data operations are involved—such as purchasing, deleting a bank account, or confirming legal responsibilities like tax declarations—the author must adhere to at least one of the following mechanisms:

Reversible: Provide a mechanism to reverse deletion or submission. For example, allowing users a specific period to cancel a transaction via letter, phone contact, or via the web, specifying the methodology and timeframe for cancellation. Additionally, consider storing deleted data for a defined period or providing a 'recycling bin' where users can retrieve deleted data before permanent deletion.

Checked: Implement a mechanism where users confirm the correctness of all input and data through a checkbox near the submission/deletion button. The implications of deletion or submission should be clearly stated in the checkbox’s label to ensure users understand the irreversible nature of their actions.

Confirmed: Offer mechanisms for reviewing, confirming, and correcting information before final submission. This is particularly relevant for multi-step forms or tests spanning multiple pages. Possible implementations include links for navigating between steps, allowing users to review and edit details, or providing a preview at the final step before submission. Depending on the application, caching or JavaScript may need to be applied, such as in SAP environments, to allow navigation between the steps.

These mechanisms aim to enhance accuracy and minimize errors in critical transactions and operations involving user inputs.

Best Practices:

  • Provide Review Screens: Display a summary of user input for review before final submission.

  • Implement Confirmation Dialogs: Ask users to confirm their actions for deletions.

  • Enable Data Correction: Allow users to correct any errors before finalizing their submission. In multi-page forms, enable navigation between pages without losing entered data.

  • Use Checkboxes for Confirmation: Require users to check a box confirming that they have reviewed the information before enabling the submit button.

  • Provide a Reversible Option: If possible, allow users the option to cancel their transaction or deletion. Ensure that the terms and policies are clearly stated in each case (e.g., the time period until it becomes irreversible)

Examples & Explanation:

Example: Online Shopping

What Should Be Avoided

A user makes an online purchase and realizes they entered the wrong shipping address.

The website processes the purchase immediately without allowing the user to review or correct the shipping address. Additionally, there is no cancellation policy or checkbox to confirm the submission.

Explanation:Users with disabilities who enter incorrect details in the data entries could face significant irreversible mistakes. In the example above, users have no options to review, confirm, or cancel the transaction.

What Should Be Done

An online shopping website allows users to cancel purchases within 24 hours after they have been made. The website explains its policy and provides instructions on how to initiate cancellation. A summary of the cancellation policy is included on the purchase receipt emailed to the user. Purchases cannot be canceled after 24 hours, at which point they will be shipped to the user.

Explanation: This implementation allows users to review and cancel their purchase within a 24-hour window, reducing the risk of errors and providing a safety net for correcting mistakes.

Next Up

Enhance your understanding with SC 3.3.7 Redundant Entry. Learn to minimize redundant entries for all users.

Go to SC 3.3.7