Every two years, Moz surveys the opinions of dozens of the world's brightest search marketers and runs correlation studies to better understand the workings of search engine algorithms. We gather this data to gain insight into the factors that may help—or hurt—a website's visibility in search engines.

This year, Moz surveyed over 150 leading search marketers who provided expert opinions on over 90 ranking factors.

In addition, the Data Science team at Moz, lead by Dr. Matthew Peters, ran an extensive correlation study to determine which features of websites and webpages are associated with higher search rankings. For the first time this year, Moz partnered with several data partners to enhance the study, including SimilarWeb, DomainTools, and Ahrefs.

Note that these factors are not "proof" of what search engines use to rank websites, but simply show the characteristics of web pages that tend to rank higher. Combining this understanding with both experience and knowledge of search engine algorithms can help lead to better SEO practices.