We've talked a lot around here about Google using user metrics to rank webpages. It's certainly an approach that would make sense, but it also opens a few questions. Assuming Google is being truthful when they say they don't use Analytics data to rank web pages: --What data could they be using to gather user metrics? Adsense? Chrome? Cookies from the Google search page to see how long searchers stay on a SERP before clicking back? --Exactly what metrics could they be gathering from their sources, and which metrics would they not be able to access? --Once they gather these metrics, how are they interpreting them? For example, can they tell the difference between a bounce that happens because a visitor got all they wanted from a site and a bounce that happens because the searcher didn't like the page?
We can only speculate, but a good guess would be Google toolbar, people signed into their accounts when searching, chrome. They have the data they need, that's for sure. Important metrics would of course be bounce rate, however, there are times when a query gives a high bounce-rate so I would assume this depends on the query (a query with a quick answer such as "what is my IP"). If they didn't like the page, of course, they would have measurements on all results in a query, but there could be many other reasons for that page to rank high. To be on the safe side, you should strive to have better bounce-rate, time on site, visitors return % and pageviews than your competitors for the keywords you want to rank for.