WCAG Levels
WCAG defines three compliance levels—A (basic usability), AA (recommended minimum for ADA compliance) and AAA (most stringent). Most sites should aim for AA, as it balances accessibility and practicality. Automated scans miss many issues, so manual testing remains essential.
The US Department of Justice has chosen to adopt the Web Content Accessibility Guidelines (WCAG) to define the standards of digital accessibility as required by the ADA. While WCAG itself is not considered law, it does define the standards by which courts and regulators measure accessibility.
WCAG is published and maintained by the World Wide Web Consortium (W3C)—an international organization that develops global internet standards. The current accessibility standard WCAG 2.2.
How WCAG is structured
Individual success criteria—defined by WCAG—are grouped by related topic. These guidelines are then organized according to the applicable POUR principle.
Each POUR principle and guideline provides background information that may help you to better understand the intent of specific accessibility requirements, which can help to implement appropriate changes. Within guidelines are the individual success criteria; where specific pass or fail requirements will be defined. Within WCAG, success criteria are assigned to one of three distinct levels of compliance: A, AA, and AAA.