The Google quality raters are contractors who work to test and judge experiments in the Google search results. They do not influence the rankings but rather give Google's engineers more data points to judge how well the algorithms are working.
Gary Illyes from Google said that these quality raters are all over the globe. He said on Twitter, the search quality raters are "in tons of countries."
They need to be because Google is a global search engine and they need to test the quality of the results in the US and in English but also in the UK, Germany, the middle east and Asia and other places.
So it makes sense Google has these folks all over the world.
Again, these quality raters have zero direct influence on how well page A ranks in Google. They just rate what they see, which is looked at by Google engineers.
Forum discussion at Twitter.
