Moz have recently released their 2015 ranking factors study, which they claim to be the largest that they’ve ever conducted on the subject.
The study, which saw Moz interview 150 SEO experts, ranks the various search ranking factors based on (a) asking industry experts their thoughts on over 90 factors and (b) using correlation studies to measure the search results and rankings. Additional data was also taken from SimilarWeb, DomainTool and Ahrefs for further accuracy.
The results indicates that links leading into a domain and page level, including the anchor text used within the links, is still the highest factor in determining where Google ranks a site. The lowest ranking factor is social metrics, TLDs and basic on-page markup.
An infographic of the results is shown below: