Error Prevention (Legal, Financial, Data)
Tier 1 · The normative floor
Baseline compliance
What the normative text of WCAG 2.2 requires, and nothing more. Only a failure of this tier is a WCAG failure.
The bare minimum
For pages that create legal commitments or financial transactions, modify or delete user-controllable data, or submit test responses, at least one is true: submissions are reversible; input is checked for errors and the user can correct them; or the user can review, confirm and correct before final submission.
Normative text
Verbatim from WCAG 2.2, W3C Recommendation 12 December 2024. Underlined terms are defined below.
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:
- 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.
Not required by the normative text
Common claims that this criterion does not support. Don't log these as WCAG failures.
- All three options. Any one satisfies it.
- Covering ordinary forms such as contact or search forms.
Definitions used (5)
Glossary definitions are normative. Their notes are informative.
- web page
-
a non-embedded resource obtained from a single URI using HTTP plus any other resources that are used in the rendering or intended to be rendered together with it by a user agent
Informative notes (2)
Although any "other resources" would be rendered together with the primary resource, they would not necessarily be rendered simultaneously with each other.
For the purposes of conformance with these guidelines, a resource must be "non-embedded" within the scope of conformance to be considered a web page.
- legal commitments
-
transactions where the person incurs a legally binding obligation or benefit
- user-controllable
-
data that is intended to be accessed by users
Informative notes (1)
This does not refer to such things as Internet logs and search engine monitoring data.
- input error
-
information provided by the user that is not accepted
Informative notes (1)
This includes:
- Information that is required by the web page but omitted by the user
- Information that is provided by the user but that falls outside the required data format or values
- mechanism
-
process or technique for achieving a result
Informative notes (2)
The mechanism may be explicitly provided in the content, or may be relied upon to be provided by either the platform or by user agents, including assistive technologies.
The mechanism needs to meet all success criteria for the conformance level claimed.
Tier 2 · The gap
Usability & user impact
Where content can meet this criterion and still make things harder for people with disabilities. These are not failures of SC 3.3.4, so raise them as usability defects. Known failures, including failures of related criteria, are listed in Tier 1.
A review step that users can click through without noticing errors technically confirms, but doesn't prevent costly mistakes.
Tier 3 · The golden path
Recommended best practice
The pattern that meets the floor, closes the gap, and avoids audit disputes. A recommendation, not a requirement.
Use a clear review page for high-stakes submissions, and allow cancellation or undo where possible.
W3C's Understanding document and techniques for SC 3.3.4 ↗ are informative: sufficient techniques show ways to pass, and documented failures show common ways to fail, but neither changes what the criterion requires.
How SC 3.3.4 maps to the WCAG 3 draft
From this site's reviewed map to the WCAG 3 editor's draft. It's an interpretation: W3C has not published a mapping.
Successor provisions
Related, not a successor
From WCAG 2.2, section 5.1: “The main content of WCAG 2.2 is normative and defines requirements that impact conformance claims. Introductory material, appendices, sections marked as "non-normative", diagrams, examples, and notes are informative (non-normative). Non-normative material provides advisory information to help interpret the guidelines but does not create requirements that impact a conformance claim.”