Why are my overall visits and my visits from traffic sources (external, direct traffic, search engines) not the same number?

Summary

The numbers differ because traffic sources only include visits from external sources, while overall visits include all sessions—including new visits created after inactivity that are counted as internal traffic.

Overview

This article explains why the total number of visits in Siteimprove Analytics may not match the sum of visits from traffic sources (external, direct traffic, search engines).

Symptoms

• Overall visits are higher than traffic source totals
• Numbers between: 
  • Analytics Overview (total visits)
  • Traffic sources (external, direct, search)
     do not match

Cause(s)

Cause 1: Session timeout creates new visits

A visit starts whenever someone enters your website and does not end until the visitor has been either inactive for 30+ minutes, has closed the browser or deleted their cookies while browsing your website.

When a user has been inactive, then resumes activity after 30 minutes, a new visit begins.

Cause 2: Internal referrer visits are excluded from traffic sources

When a new visit begins after inactivity, the visit would be an internal referrer and would not be listed in the traffic sources section.

We can see in the following example that the total number of visits from traffic sources (external referrers, direct traffic, and search engines) counts to 93,137 visits.

For the same period, overall visits are higher - totaling 100,591 visits.