Overall, the presence of relevant words on a page (i.e., not just an exact match with the search term) has the strongest correlation with positive search rank. Social signals (Google +1s, Facebook shares, Pinterest pins, tweets, etc.) also tend to have very positive impact on search rank, as does the number of backlinks.
Google has been tying rank on search engine results pages (SERPs) to content quality for years, and the analysis found this trend accelerated significantly with the Hummingbird algorithm update last fall.
The report also found that Google does not seem to favor pages that meet certain traditional SEO criteria, such as fast load times and short URLs; rather, it is the absence of those criteria that seems have a negative effect on the ranking. When it comes to keywords in a site’s domain/URL has dropped from being positively correlated with search rank in 2012 to now being zero/slightly negatively correlated.
View the report outline.