If you've been working with Universal Analytics for a while now, you are probably familiar with the metric Average Session Duration, which is how much time on average a session lasted. However, since migrating to Google Analytics 4, you might notice that there is a different metric that shows up by default in all your channel reporting which is called "Average Engagement Time Per Session". Another thing you might have noticed is that the value of Avg. Session Duration is different compared to the Avg. Engagement Time per Session. This guide will talk about the difference between Avg. Session Duration and Avg. Engagement Time per Session in Google Analytics 4 (GA4). Let's get started!
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How to Display the Metric Avg. Session Duration
To reiterate, the two metrics Avg. Session Duration and Avg. Engagement Time per Session is actually different. Let's actually compare them side by side to see the difference!
If you navigate to your Traffic Acquisition Report, you'll find that the Avg. Engagement Time per Session is displayed by default in the table.
To display the metric Avg. Session Duration, you can click on the pen symbol to Customize Report.
Under Metric, click on "add metric" and find the Avg. Session Duration.
You can reorder the position of the metrics to be side by side so you can compare them easily. Click on "Apply" and save the changes to your current report.
Now you'll be able to see both metrics in your report.
What is the Difference between Avg. Engagement Time per Session and Avg. Session Duration
As you can see on the report, in terms of numbers, the two metrics are completely different. The Avg. Engagement Time per Session is lower than the Avg. Session Duration. This is because the Avg. Engagement Time per Session calculates only the time that the users are active on your website. Active means that the user is on the screen where your website is displayed as the focus of the user's browser and is actively interacting with your website. The key here is the word Engagement. Engagement means the user is actively interacting with the website.
Avg. Session. Duration doesn't take into account if your website's tab is the focus on the user's screen or if the user is actively engaging with your website. It takes into account how long the entire session lasted until it expires or until the user leaves the website and closes the tab. This is why the number is much higher than the Avg. Engagement Time per Session. For the metric Avg. Session Duration, the user doesn't have to actively be on the site for the metric to populate a user's time on site.
Average Engagement Time per Session: The length of time that your web page or mobile app was the focus on a user's screen - meaning that the user was actively using your website or mobile app.
Average Session Duration: The total duration of all engaged sessions (in seconds) divided by the number of sessions.