Average Session Duration: The Misunderstood Metric

Google Analytics is a great tool to help you understand how users interact with your website. You can go as in-depth as you want with your data, but most users generally just stick to the basic overviews. The main metrics that most everyone pays attention to are sessions, bounce rates, users, and session duration.

Each produces their own set of unique data on how a user interacts with your site. However, as simple and straightforward the data may seem, there is one metric in particular that is often misunderstood: session duration.

If you haven’t already guessed it, session duration provides you with the average amount of time a user spends on your website. Seems pretty candid right? It’s easy to take this metric at face value, however it should be taken instead with a grain of salt.

How Session Duration is Measured

A session is considered a visit to your website. The session starts once a user lands on a page on your website, and ends either once they leave the site or if they have been inactive for over 30 minutes. You can adjust this time if needed, but 30 minutes is the default time that is set in Analytics.

A session duration is calculated by taking the total duration (in second) of all sessions during a set period of time, and dividing it by the total number of sessions during that same time period.

Here is an example:

• Tim is on the site for 22 seconds
• Jane is on the site for 400 seconds
• Stephanie is on the site for 40 seconds
• Joe is on the site for 150 seconds

To calculate our average session duration, we would add the duration of each individual session (22 + 400 + 40 + 150) and then divide it (612) by the total number of sessions (4) to get our average session duration of 153 seconds (2 minutes and 55 seconds).

Even though this seems simple and straightforward, there is a caveat. Google does not know how long someone has spent on a page until that user has taken some sort of action on said page.

Here’s another example. Let’s say a user lands on a blog page of your site and spends around 4 minutes reading through the article. They saw a link on the page to another interesting article, so they click to that page and spend another 6 minutes there, before ultimately leaving the site. How long would Google count as their average session duration? 4 minutes.

Google will not count the exit page as part of the session because no action had been taken on that page. Without a user engaging with some element on the site, such as a video play, link click, form fill, etc. Google will not know how long they spent on that page

The same can be said about single page visits. If a user spent 4 minutes reading the article they landed on, but didn’t click to another page, that would be calculated as 00:00:00 for the session duration.

You can see why this metric can be difficult to get an accurate gauge on, and why it shouldn’t be taken at face value.

Why Does this Matter?

By knowing how long users spend on your website, you can better understand how engaging your content is, and what type of content is helping to drive the most qualified traffic to your site.

You should use session duration in tangent with other metrics, like bounce rate and avg. pages per session. This will help you gain a better understanding of where you are doing well, and where you need to improve. If you have a low session duration, it’s likely that you also have a high bounce rate. Learning to read these signals will help you to make improvements to your site.

Another thing to consider is how RankBrain perceives user satisfaction with your site. RankBrain will use metrics such as session duration and bounce rate to help determine if a user found your content relevant to their searched query. If users are continually bouncing off of your site, RankBrain may feel you are irrelevant and drop you in the search results.

Reasons for Low Session Duration

This can be difficult to figure out, but there are a few main factors to consider. Is your content relevant, and are users resonating with it? Take a look at all of the pages on your website and see which ones have a low session duration and how they differ from pages that have high session durations.

Another issue may simply be poor website design. If your website is providing a negative user experience due to information being difficult to find or a confusing navigation, then users may get easily frustrated and leave the site quickly.

How to Improve Session Duration

You will want to consider adding elements to your site to help encourage user engagement. A few things to look at are:

Proper formatting of content: Having large blocks of text can be discouraging for readers and cause them to feel overwhelmed. You will make sure to use short paragraphs, bulleted lists, subheadings, etc. Anything that will help to make the content easier to scan.

Images: Adding images is another way to help break up the text and make it more engaging. Make sure the images are relevant and add value to the content.

Videos: Videos are a great way to get users to spend a longer amount of time on the page, and they usually require a user to take some sort of action (playing the video). Similar to images, make sure the video is adding value to the page and is relevant to the content.

Links: Adding various links throughout the page is a simple, yet effective tactic. If you have similar content that a user might want to read, be sure to add those links to the page.

Make sure you have quality content: Many in the SEO community will tell you that quality content is key, and they aren’t wrong. We touched on this a little bit before, but if a user is leaving your site quickly, you might have a content issue. Make sure that when you write content, you have your target audience in mind. What type of content would they be looking for? What kind of tone should the content have? What sort of information do they want to see?

Even though your average session duration can be misleading, you shouldn’t obsess over it. They are a lot of different factors at play and the main thing you should consider is your website as a whole. It’s important to have a good understanding of how session duration is calculated so you can find ways to improve your website, but it shouldn't be the main focus when analyzing your Google Analytics data.