Category: WCAG Principles and Conformance

Success Criteria

Also known as: WCAG Success Criteria

Simply put

In the context of digital accessibility, success criteria are the specific, testable statements in the Web Content Accessibility Guidelines (WCAG) that describe what content must do to be considered accessible. Each success criterion sets a checkpoint that can be evaluated to determine whether a piece of content meets a given accessibility requirement. Note that the evidence provided for this entry does not address accessibility-specific success criteria and instead covers the term as used in education and project management.

Formal definition

Success criteria, as used generally, are measurable or testable standards that indicate whether a defined goal or deliverable has been achieved, functioning as checkpoints against an intended outcome. In educational settings the term describes what learners will be able to do relative to a learning intention, and in project management it refers to measurable standards signaling that project goals and deliverables have been met. The accessibility-specific meaning of 'Success Criteria' as WCAG conformance requirements (organized under levels A, AA, and AAA across WCAG versions 2.0, 2.1, and 2.2) could not be substantiated from the supplied evidence, which contains only education and project-management sources; practitioners should consult the W3C Web Accessibility Initiative's published WCAG documentation for the authoritative definition and version-specific criteria. This entry is informational and not legal advice.

Why it matters

In digital accessibility, success criteria are the backbone of how conformance is measured. The Web Content Accessibility Guidelines (WCAG), published by the W3C through the Web Accessibility Initiative, express their requirements as discrete, testable success criteria. Because each criterion is written to be evaluated for pass or fail, they give teams a shared, defensible reference point for determining whether content meets an accessibility requirement rather than relying on subjective judgment. This matters for compliance officers, engineers, and legal counsel alike, since WCAG success criteria are frequently cited as a benchmark in accessibility settlements and agency guidance, even though the ADA itself does not codify a specific version of WCAG.

The concept of success criteria also appears in other disciplines, and the evidence available for this entry draws from education and project management rather than accessibility. In classroom formative assessment, success criteria describe what learners will be able to do relative to a learning intention, often framed as checkpoints on a roadmap toward a learning goal. In project management, they are described as measurable standards indicating whether project goals and deliverables have been achieved. These parallel uses share a common logic with the accessibility meaning: a clear, testable statement of what an outcome must satisfy.

Readers should be aware of an important limitation. The sourced evidence for this entry covers only the education and project-management senses of the term and does not substantiate the accessibility-specific meaning. Practitioners seeking the authoritative, version-specific definition of WCAG success criteria should consult the W3C Web Accessibility Initiative's published WCAG documentation directly. This entry is informational and does not constitute legal advice.

Who it's relevant to

Accessibility engineers and QA testers

Practitioners who evaluate whether content conforms to WCAG rely on success criteria as the testable checkpoints against which they assess a page or component. They should reference the W3C's authoritative WCAG documentation for the precise criteria and understand that automated checks alone cannot confirm that a criterion is fully satisfied; manual and assistive technology testing are commonly needed.

Compliance officers and legal counsel

Those assessing accessibility obligations often encounter WCAG success criteria cited as a benchmark in settlements and agency guidance. Because the ADA does not itself codify a specific WCAG version, these readers should treat conformance with success criteria as a measure that may support compliance efforts rather than a guarantee of legal immunity, and should consult qualified legal counsel and current rulemaking.

Educators and instructional designers

In the education context reflected in the evidence, success criteria describe what learners will be able to do relative to a learning intention and serve as checkpoints in formative assessment. Educators use them to communicate expectations clearly and to gauge progress toward a learning goal.

Project managers

In project management, success criteria are measurable standards indicating whether project goals and deliverables have been achieved, offering a clear framework for defining and evaluating project success.

Inside Success Criteria

Testable Statements

Each success criterion is written as a testable statement that can be evaluated as either satisfied or not satisfied for a given piece of web content, allowing for consistent determination of conformance.

Conformance Levels (A, AA, AAA)

Every success criterion is assigned to one of three conformance levels. Level A represents the most essential criteria, Level AA builds on Level A and is the level most commonly cited as a target, and Level AAA represents the highest and most demanding level. Meeting a higher level generally requires also satisfying the criteria at lower levels.

Association with Guidelines and Principles

Success criteria sit beneath WCAG's four guiding principles (Perceivable, Operable, Understandable, Robust) and their associated guidelines, providing the specific, measurable requirements that support each broader guideline.

Version-Specific Additions

The set of success criteria differs across WCAG versions. WCAG 2.1 added criteria beyond WCAG 2.0, and WCAG 2.2 added further criteria, so practitioners should confirm which version and which criteria they are referencing rather than assuming the sets are identical.

Supporting Techniques and Understanding Documents

The W3C publishes accompanying non-normative materials, such as sufficient and advisory techniques and 'Understanding' documents, that explain how criteria may be met, though these are informative rather than part of the normative requirement itself.

Common questions

Answers to the questions practitioners most commonly ask about Success Criteria.

Does meeting all the WCAG success criteria guarantee that my site is legally compliant with the ADA?

No. Success criteria are technical benchmarks published by the W3C through the Web Accessibility Initiative, not a codified legal standard. The ADA is a US civil rights law that does not itself contain detailed web technical specifications, and courts and settlements have often referenced WCAG as a benchmark rather than a fixed rule. Conforming to success criteria may support a strong accessibility position, but it does not guarantee immunity from legal claims. Requirements evolve through regulation and case law, and this is not legal advice; consult qualified legal counsel for your specific situation.

If my site passes an automated accessibility scan against the success criteria, does that mean the criteria are fully satisfied?

Not necessarily. Automated testing detects only a portion of potential issues. Many success criteria require human judgment to evaluate correctly, so manual review and testing with assistive technologies are generally needed to assess conformance. Passing automated checks also does not guarantee an accessible experience for all users. Automated tools are best treated as one part of a broader evaluation process rather than a complete measure of whether success criteria are met.

Which conformance level of success criteria should I typically aim for?

Level AA is the level most commonly cited as a target in settlements, guidance, and organizational policies. Success criteria are organized into three levels, A, AA, and AAA, where AA generally encompasses the Level A criteria plus additional AA criteria. AAA is often considered aspirational and is not commonly expected as a blanket target across an entire site. The appropriate target for your organization may depend on applicable authority, agency guidance, and legal considerations, so confirm your specific obligations with qualified counsel.

How do I know which success criteria apply if my organization uses more than one WCAG version?

Success criteria differ across WCAG versions, with WCAG 2.1 and 2.2 adding criteria beyond WCAG 2.0. When documenting conformance, it is important to state which version and level you are evaluating against, because a criterion added in a later version would not appear in an earlier one. Confirm which version your applicable authority, regulation, or agency guidance references, and evaluate against that version's specific criteria and levels rather than assuming they are interchangeable.

What testing approach helps confirm that individual success criteria are met?

A combined approach is generally recommended. Automated tools can flag certain issues efficiently, but manual review and testing with assistive technologies such as screen readers, keyboard-only navigation, and magnification are typically required to evaluate criteria that depend on human judgment. Because automated testing detects only a portion of issues, relying on it alone can leave criteria appearing satisfied when they are not. Documenting how each criterion was tested supports a defensible record of conformance efforts.

How should I document conformance with specific success criteria?

It is common to record the WCAG version and conformance level being targeted, identify each relevant success criterion, and note the method used to evaluate it, including whether it was assessed through automated tools, manual review, or assistive technology testing. Because conformance is distinct from usability and from legal compliance, documentation should describe what was evaluated and its limitations rather than asserting full compliance. Keeping this record current matters, since standards and legal expectations evolve over time.

Common misconceptions

Meeting all applicable WCAG success criteria guarantees an accessible experience and legal compliance.

Satisfying success criteria does not guarantee a usable experience for all people with disabilities, nor does it guarantee immunity from legal claims. Conformance, usability, and legal compliance are distinct. Requirements can also be shaped by regulation and case law, and readers should consult qualified legal counsel for their specific situation.

Automated tools can verify that content meets all success criteria.

Automated testing detects only a portion of potential issues. Many success criteria require human judgment, so manual review and testing with assistive technologies are generally needed to evaluate conformance accurately.

A success criterion belongs to the same conformance level and exists in every version of WCAG.

Criteria are assigned to specific levels (A, AA, or AAA) and some were introduced only in later versions, such as WCAG 2.1 or 2.2. Practitioners should not conflate criteria across versions or assume a criterion's level without checking the relevant WCAG version.

Best practices

Identify the specific WCAG version (2.0, 2.1, or 2.2) and target conformance level (commonly AA) you are evaluating against, and document which criteria apply.

Combine automated checks with manual review and testing using assistive technologies, since automated tools detect only a portion of issues.

Treat each success criterion as a testable pass/fail statement and confirm its assigned level rather than assuming, noting when a criterion was added in a later version.

Consult the W3C's 'Understanding' documents and techniques for guidance on how a criterion may be met, while recognizing those materials are informative rather than normative requirements.

Distinguish conformance from real-world usability by validating with users and reviewers where feasible, rather than relying solely on criterion satisfaction.

Recognize that meeting success criteria does not by itself ensure legal compliance, and consult qualified legal counsel and current agency guidance for jurisdiction-specific obligations.