In this post of my Google Analytics 101 series I examine session duration vs time on page. Both metrics are engagement metrics, which help you understand how your users are interacting with your site. To learn about another engagement metric, bounce rates, check out this post.
Google Analytics offers both metrics as a way to determine time on site. However, they are calculated differently and are used in different parts of Google Analytics. This can lead to disparity between the numbers and it can be difficult to figure out which one to use. This post looks to explore both metrics.
Finding Session Duration and Time on Page
Session duration and time on page reside in two reports within Google Analytics.
Session Duration, or more precisely Avg Session Duration, is found can be found under the Acquisition reports. Specifically they are found in Acquisition > All Traffic > Source/Medium. In this report it is the sixth metric. It is to the right of Pages/Session.
Time on Page, or more precisely Avg Time on Page, is under the Behavior reports. The most used report that has Time on Page is the Behavior > Site Content > All Pages. This report shows metrics related to specific pages on your site. Time on Page is the third metric.
Session Duration Calculation
Avg Session Duration is calculated as Total Session Duration divided by Total Sessions. So if you had 600 seconds of session duration and 100 sessions, then the Avg Session Duration would be 6 seconds.
Notice that this calculation includes all sessions, even bounced sessions. To learn more about the session duration calculation I recommend the Google Analytics Documentation.
Time on Page Calculation
Avg Time on Page is calculated as Total Time on Page divided by (Page Views minus Exits). So if you have 600 seconds on a page, 200 page views, and 100 exits, then your Avg time on page would be 6 seconds.
Notice how this calculation only includes users who clicked on another page on the site. By doing this the calculation excludes bounces. The denominator is page views that led to another page view.
Session Duration vs Time on Page
So which is best? The answer is that it depends.
Avg Session Duration shows you the average amount of time a all visitors spent on your site including bounces. There are times when this is helpful, and times when it is not helpful. If you wanted to know how much time an engaged user spend on the site Avg Session Duration is not the metric to use.
If you curious how much time an engaged user spent on your site, then Avg Time on Page is likely to be better. This is because it only includes users who view another page after the page in question. Looking at the site average Time on Page is an excellent metric to see how long non-bounces are staying on your site.
Personally, I prefer time on page. While bounces are important, i think they muddy the water when it comes to looking at time spent on a site and overall engagement. That is not to say Avg Session Duration has no use. It does. But that use is limited to observing traffic, and not evaluating content or site performance.
