How time on site is calculated and why you should beware of the bounce rate

Is your web site capturing your visitors’ attention?

One of the best ways to tell is by looking at how long they spend on it and, in particular, which pages are keeping their interest the longest.

If they don’t stay long, then maybe people are coming to your site by mistake or the content needs improving. If they are staying a long time but not buying anything, then maybe the information is unclear or people are having problems working the site.

But to make a valid judgement you need to understand how these values are calculated.

How time on site is calculated

Google Analytics only knows when someone loads a web page or clicks on it and triggers more information to be sent back to Google.

So it will know when they arrive on the page and it may receive information that tells it they are still there.

But what Google doesn’t know is if they have left.

To get around this problem Google Analytics makes the assumption that the visitor has finished on a page once they open another page on the same website. It uses the opening time for the next page as the closing time for the previous one.

This works well until the visitor reaches the last page they look at.

Being the last page there is no next-page opened, so Google will not have a leaving time. Hence, the time spent on this page will be excluded from all of the time statistics reported in Google Analytics.

The only exception to this is if there are any interactions on the page set up to be recorded by Google Analytics, such as through event tracking, then it will use the time the last one of these was recorded as the time the visitor left the page.

So we have good information for all except the last pages. But the real problem comes when the last page is also the only page that the visitor looks at.

The affect of bounces on time on site

A bounce is the term used to describe a visit in which the visitor only views one page of a website.

In other words they do not explore the site they just stay on their entrance page.

Because bounce visitors only visit one page, Google Analytics only knows when they arrive and not when they leave. It therefore assumes a nil value for time they are on the page.

For sites with even a moderate bounce rate this can seriously skew any average time on site metric and you might find it makes more sense to exclude these visits when analysing the time on site statistics.

The importance of time on site

Time on site represents direct feedback from your visitors and it is a good barometer for how interesting your visitors are finding your website and how well it is working. But don’t forget to take the bounce rate into account.