The Accessibility Guidelines Working Group (AGWG) has published Accessibility Conformance Testing (ACT) Rules Format 1.0 as a W3C Recommendation (web standard). This standard helps developers of automated testing tools and manual testing methodologies to write, share, and implement test rules, to contribute to common testing practices for accessibility. Read the blog post Calibrate Your Accessibility Evaluation With ACT for more background and examples of organizations already using ACT.

Original source: https://www.w3.org/blog/news/archives/8021