I have been going through WCAG 2.0 guidelines and I couldnt find any reference to the letter 'A' in Conformance levels of A, AA & AAA standards. What does letter 'A' stand for ? Is it an abbreviation for accessibility ?

  • 1
    Perhaps these are variations on an 'A' grade? So when A, B, C grades denote best, good, medium, A, AA and AAA denote best, bester, bestest? (tongue in cheek...) Commented Jun 16, 2019 at 7:42
  • Most likely it is for accessibility. Hence the levels for accessibility. Commented Jun 17, 2019 at 7:46
  • Similar to @Hans-MartinMosner's comment, possibly (but with no references) something I've just called preemptive grade saturation. E.g. in Europe, "white goods" were originally graded G (poor) to A (good). With better manufacturing (and more stringent limits), there is now A, A+ through to A+++ (and, generally, I believe, new machines can only be "A-something"). They could have chosen C, B, A for A, AA, AAA, but then what do they use for "better than A". With the current scheme, they can add AAAA if needed.
    – TripeHound
    Commented Jun 17, 2019 at 10:57
  • As the first letter in the english alphabet, 'A' is just used to denote first or best, and since there's no more letters before it to denote something even better, extra A's or +'s or *'s (UK school exam grades now include A* as a higher rank than A) are used. One exception is UK road numbering, initially A roads were the highest quality, followed by B roads, followed by C (usually unsigned). When motorways were introduced they labelled them M rather than A+ :-)
    – mgraham
    Commented Jun 18, 2019 at 15:38
  • 1
    I'm voting to close this question as off-topic because is not important info. Commented Jun 19, 2019 at 17:58

2 Answers 2


WCAG 1.0, published in 1999, assigned priorities to checkpoints and defined three conformance levels: Level "A", Level "Double-A" and Level "Triple-A".

Early drafts of WCAG 2.0 did not assign priorities to "checkpoints", as they were still known, but planned this for later. See "Priorities and Techniques" in the August 2001 working draft. By April 2003, the conformance levels were named "Minimum Level", "Level 2" and "Level 3", and each of the checkpoints had "levels of implementation listed for it". In the June 2003 working draft, the conformance levels had been renamed to "WCAG 2.0 Core", "WCAG 2.0 Core+" (i.e. for site meeting "Core" and some of the "Extended checkpoints") and "WCAG 2.0 Extended" (for sites meeting all checkpoints). By that time, it was clear that the term "priorities" when referring to WCAG 1.0 checkpoints.

By November 2004 checkpoints had been renamed to "success criteria", which were categorised into three levels: "Level 1", "Level 2" and "Level 3". Conformance levels were called "level A", "level Double-A" and "level Triple-A" (see WCAG 1.0, above). The April 2006 draft was the last one that used numbered levels for success criteria (Level 1, 2, 3) and the letter scheme for conformance levels; the May 2017 draft used A, AA and AAA for both conformance levels and success criteria.

What can be seen from the above comparisons is that two things happened:

  1. WCAG 2.0 got rid of the term "priority" (from WCAG 1.0).
  2. WCAG 2.0 rejected alternatives such as "Minimum Level", "Core" versus "Extended", and numbered-based level identifiers. (A number of other schemes were discussed internally but never made it into a public working draft, e.g. "Gold", "Silver", "Bronze".)

The main rationale was that disability groups are not equally represented in the success criteria at each level (especially those with cognitive impairments or learning disabilities) and the WCAG working group wanted to avoid making the impression that any disability group is less important than other disability groups (i.e. by being less well represented at level A or AA). This meant that a naming scheme that suggested that the "higher" conformance levels encompassed the "lower" levels (like matryoshka dolls) was fine, but anything that suggested priority or higher importance of certain disability groups had to be avoided. The naming scheme "Level A", "Level AAA", "Level AAA" achieves this. As far as I know, the "A" is not intended as an abbreviation of anything: the oldest mention I found on the working group's mailing list dates from March 1999, when Daniel Dardaillier wrote:

For what it's worth, at the time this conformance schema was discussed, I suggested A, AA and AAA.

This suggestion reminded some people of the grading system used in North America (see Eric Hansen's response from the same day), rather than seeing the "A" as an abbrevation for accessibility. In addition, when I was a member of the WCAG working group (especially 2005-2008), "A" was never discussed as an abbreviation of anything.

  • 1
    Just the last paragraph would have been sufficient...
    – user68158
    Commented Jul 10, 2019 at 8:01

Not sure what it stands for but it was decided back in the first version.

Conformance Level "A": all Priority 1 checkpoints are satisfied;

Conformance Level "Double-A": all Priority 1 and 2 checkpoints are satisfied;

Conformance Level "Triple-A": all Priority 1, 2, and 3 checkpoints are satisfied;

  • 3
    This describes what they are used for, but not why 'A' was used in the first place.
    – JonW
    Commented Jun 17, 2019 at 10:46
  • Exactly. I couldn't find any reference in WCAG website for the reason for using letter 'A'
    – Sooraj MV
    Commented Jun 17, 2019 at 23:11

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