Google Quality Rater Guidelines

Google Quality Rater Guidelines (QRG) are Google's official document describing how human evaluators assess website quality. They distinguish Main Content (content directly fulfilling the page's purpose), Supplementary Content (navigation, ads, sidebars), and E-E-A-T criteria (Experience, Expertise, Authority, Trust).

In semantic SEO context, QRG defines what Google considers 'quality': high Information Density, no fluff, visible authority and experience signals. QRG serves as the source of weights in CQS audit, where E-E-A-T has a weight of 0.20 (second highest after CSI Alignment) and sets standards for content optimized for AI Search.

In practice, it's worth reading the Main Content section in QRG. Google clearly states that any page element not directly fulfilling the page's purpose is Supplementary Content and shouldn't dominate. QRG evolves and gets updated, making it a living document influencing algorithms — changes in QRG often foreshadow algorithm changes.