Analytics: Why is there no "Time on page" data available?

You may have noticed that "Time on page" or "Time spent on page" (meaning one specific page) data is not displayed within the Siteimprove Analytics module. Siteimprove does not show this data as it is generally unreliable.

Let's take an example:
A visitor comes to your website and opens a page in a new tab. The visitor leaves the tab open for 30 minutes. Apart from the visitor that keeps his tab open for 30 minutes, all other visitors to the page stay on the page for only five seconds.

The above scenario would influence any data collected for "Time spent on page" and give an incorrect impression of how long visitors were on the individual page.

Furthermore, the "Time spent on page" data would be incomplete in cases where a visitor only visits one page on your website and then leaves the website again (bounces). In order to see the visitors time on a page, Siteimprove would technically need to know when the visitor clicks on the page and then clicks on another link on the same website.

Because the data regarding "Time spent on page" is unreliable, Siteimprove has opted to show the more reliable metric Visit length* (the time spent on a website). 

*Visit length can be found under the Behavior menu. Length relates to the time (in minutes) for each visit. This data can be used to determine how your website retains a visitor - if the visit length is typically low, you could investigate ways to keep your visitors on your site for longer.