Conformance Level

The three-tiered classification system used by WCAG to rank success criteria by their importance and impact on accessibility. Level A represents the minimum baseline — criteria that must be met or some users will be completely unable to access content. Level AA addresses the most common barriers and is the standard referenced by most accessibility legislation worldwide, including the EU Web Accessibility Directive and Section 508. Level AAA represents the highest level of accessibility support but is not required as a general policy because it is not achievable for all content types.