Last week Google Analytics changed the way the session (or visit) is calculated. Why is this so important? Because your past information will not change, just from now on, ergo when you analyze trends you will identify a variation in you reports comparing before and after the new visit definition, so the first thing you have to do is loading a new event note in your Google Analytics platform so when you analyze the information in the future it will be easy to understand the cause of the variation.
Last visit or session definition:
More than 30 minutes have elapsed between pageview for a single visitor. No changes.
At the end of a day. No Changes.
When a visitor closes their browser: It changes by “When any traffic source value for the user changes. Traffic source information includes: utm_source, utm_medium, utm_term, utm_content, utm_id, utm_campaign, and gclid”.
How is this new session definition different?
Basically if the person leave your site and come back from a different source (any of the above mentioned values changed) this will count as a new session. According to Google, this change will just generate a variation of not more than 1%.
Important Note from Google, remember add a note in your platform:
Update 8/17/2011 2:10 PM PST:
“We identified an issue responsible for unexpected traffic changes following our recent update to how sessions are defined in Google Analytics. A fix was released at 2pm PST Tuesday August 16th”.
The issue affected some sites using the following configurations:
1. If a user comes to a customer’s site with a space in some part of their traffic source data, then revisit the same landing page during that session by refreshing the page or later pressing the back button, a new session will be created for every hit to that page. (Clicking a link elsewhere on the site that leads back to the page should not matter.)
2. Google Analytics implementations using multiple trackers (an unsupported configuration) are also affected when a space is included in the traffic source data. These sites will see fewer visits from new visitors, and more visits from returning visitors (with some variation due to different implementations).