This measure is slightly more complicated than regular awareness metrics such as page views or visitors. Time spent on a page is essentially a measure of duration bookended by two actions:
- A page gets loaded.
- The page eventually gets closed or replaced by another (or the session times out).
All time spent calculations are therefore a difference between the time stamps of two actions on the site.
One major issue with this relates to exit pages (more on that below), and another pertains to the tabs visitors have open in their browser that they are not actively engaged with. Yehoshua Coren has some great ideas for addressing these issues. What we deal with in this post is the issue with exit pages.
Some good sources to get a more in-depth understanding of this particular GA function include Google’s help pages, this classic post by Justin Cutroni and another by Analytics Edge. These posts will also bring to light some of the issues with Google’s default implementation.
- The importance of exit pages
The last page of a visit to a website is called the exit page, and it has a big influence on how time on page is calculated. When a visitor closes a tab or navigates to another site from a page, that page is marked as an exit page.
The number of times visitors exit a particular page divided by the total page views gives you the exit rate for that page — it tells you how likely the visitors are to end their journey of your site on a page. If you run an e-commerce site, for example, the final “thank you” page after checking out a product would be a likely candidate for a high exit rate as most visits would end there.
Looking at exit rate values is important for scenarios where the goal is to have visitors follow a certain path and helps you analyze if they are dropping out at unintended stops in this journey.
- How exits influence time on page
Now we get to the heart of the matter. Pages with a high exit rate have time on page values that fluctuate a lot. An exit from a page doesn’t provide that second time stamp GA needs to calculate the time the user spent on the last page. Sessions and page views without additional engagement officially log as 0:00 in Google Analytics, whether the user spent two seconds or 20 minutes on the page.
The standard implementation of GA lacks any custom events to regularly ping GA to record the time spent values that can be used in case of an exit. And even if such events are added, the formula GA uses poses another problem.