Glossary · Accessibility term
Guideline
A guideline is the middle layer of WCAG, and WCAG 2.2 has 13 of them sitting between the four principles and the rules anybody is ever tested against. Each one states a goal in a sentence, such as making it easier to see and hear content, or providing ways to help users navigate and find things. Nothing is ever measured against a guideline, which is the odd and useful part. Guidelines are binding content inside the standard and they are not testable, because what gets tested is the success criteria underneath them, alongside four conformance requirements that sit outside the criteria entirely. Once you know that, the numbering reads itself. In 1.4.3 the first digit is the principle, the second names the guideline, and the third is the criterion, so 1.4.3 is Perceivable, then Distinguishable, then Contrast (Minimum).
In practice
The layer is worth knowing mainly so you can tell an argument about a goal from an argument about a rule. Somebody can point at guideline 2.4, which asks for ways to help users navigate, find content and know where they are, and say a site fails it while passing every criterion inside it. They may well be right about the experience, and they are not describing a conformance failure. Those are two different conversations and they get mixed constantly.
The distribution is lopsided in a way the four-principle picture hides. Perceivable has four guidelines, Operable five, Understandable three, and Robust exactly one. That single Robust guideline carries two criteria after Parsing was removed in WCAG 2.2, which is why so few rules there break so many sites. That is the whole of Robust.
The numbering is stable across versions on purpose, and that stability is why an old citation still resolves. Criteria added in 2.1 and 2.2 were appended to the end of their guideline rather than triggering a renumber, so 1.4.3 has meant the same thing since 2008. One guideline is genuinely new. WCAG 2.1 added 2.5 Input Modalities for pointer, touch and speech input, which is why 12 guidelines became 13. The side effect of appending is that numeric order inside a guideline no longer tells you the level. In Navigable, 2.4.10 is AAA and 2.4.11 is AA.
Why it matters
Knowing the shape of the standard turns it from a wall of 86 rules into 13 goals with tests attached, and it is the fastest way to find the rule you actually need. It also answers the most common contract question. WCAG 2.2 uses the same conformance model as 2.0, and content conforming to 2.2 conforms to 2.0 and 2.1 as well, so building to the newest version is never the wrong technical target. The reporting has one wrinkle. WCAG 2.2 removed a criterion, so a report written against an older obligation may still want a row for the one 2.2 no longer tests.
Reading a rule number
1.4.3 breaks into three parts. Principle 1, Perceivable. Guideline 1.4, Distinguishable, which is the goal of making content easier to see and hear. Criterion 3, Contrast (Minimum), which is the testable part and the only part conformance is ever measured against.
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Related terms
- WCAGWCAG is the international standard for web accessibility, published by the W3C.
- Success criterionA success criterion is a single testable rule in WCAG, and it is the unit everything else is built from.
- POURPOUR is the field's shorthand for WCAG's four principles, which are Perceivable, Operable, Understandable and Robust.
- Level A, AA, AAALevel A, AA and AAA are WCAG's three conformance levels, and they stack.
- TechniqueA technique is one of the W3C's documented ways of meeting, or of failing, a WCAG rule.
Knowing the word is the easy part.
Find out where your own site stands. The free scan checks 10 pages in a real browser against all 90 supported automated rules, separates 27 best-practice checks from its WCAG findings, and names the rule behind every result.