Quality raters, also called search quality evaluators, are people hired through contractors to assess Google search results against the Search Quality Rater Guidelines. They work in many countries and languages, rating page quality and how well results meet a query's need. Google uses their aggregated ratings to judge whether changes to its ranking systems make results better before rolling them out. Raters do not decide where any individual site ranks.
What raters actually do
Raters receive tasks such as comparing two sets of results for a query, or rating a single result for quality and usefulness. One common setup is a side-by-side experiment: one set of results comes from the current system and the other from a proposed change. If raters consistently prefer the change, that is evidence it improves search.
What they do not do
Raters cannot demote or promote a site. Their ratings are not used as direct inputs to rankings for the pages they review. The manual actions that do affect individual sites come from a separate team that enforces spam policies.
Why marketers should care
Because raters are the yardstick for Google's experiments, systems that get launched tend to align with rater preferences. So the guidelines raters follow describe the kind of results Google wants its systems to produce over time.
Common mistakes
Worrying that a rater visited your site
A rater seeing your page has no direct effect on its rankings.
Questions
Raters are hired through third-party vendors that recruit for search evaluation work. Google itself does not hire raters directly.
