Scroll Depth term explained
Scroll Depth — is the number of visited pages within a session, one of the most important behavioral factors to calculate the relevance of a resource for key words and important indicator of the quality of the resource. The Analytics services, there is another interpretation of what the depth of view is the average of all visitors to the project, which is calculated according to the formula: total number of hits/number of visits.
Depth of view allows to determine the usability of the site and quality of content to users coming from search engines. For example, 1-2 pages viewed could indicate uninformative, or confusing site structure.