Google announced an update to sessions in Google Analytics. The company says it will lead to a “clearer understanding of website interactions.”

As it stands now, GA ends a session when over 30 minutes have elapsed between pageviews for a single visitor, at the end of the day, and when a visitor closes their browser. In such cases, the next pageview from the visitor will start a new session.

Now, GA will end a session when over 30 minutes have elapsed between pageviews for a single visitor, at the end of the day, and when any traffic source value for the user changes.

Google says traffic source info includes:

• utm_source
• utm_medium
• utm_term
• utm_content
• utm_id
• utm_campaign
• gclid

Trevor Claiborne of the Google Analytics team says on the Analytics Blog:

This change only applies for visits going forward from today, and your historical data will not change. We’re bringing the definition of session in line with the common definition of a visit. If a visitor leaves your site and returns soon after with a different traffic source value, each visit will be measured with its own session.

Since Google Analytics will start new sessions for all new campaign information, sessions will now have the more accurate attribution information. This will be especially helpful if you use Multi-Channel Funnels. Additionally, by continuing a session when the user closes their browser for only a very short time, sessions will more accurately model a user’s engagement with the website. Overall, this change may slightly increase the number of visits. Based on our research, most users will see less than a 1% change.

Google also added some stuff to custom reports in Google Analytics this week. This includes 45 new metrics/dimensions, a simplified report builder and the ability to build entire groups of reports.