Google Analytics: Bounce Visits are excluded for Avg. Time On Site

2007-07-26 by Yohay

Google Analytics stopped counting bounce visits when calculating the average time on site. The new numbers began showing up on July 20th.

I finally received a satisfying answer from the Google Analytics support team, following this post. This explains the jump in the Avg. time on site metric.
Here’s a quote from their support team:

Previously, the Average Time on Site had been calculated as the total time on site for all visits divided by the total number of visits. Both the total time on site and total number of visits included bounces.

As of July 20, 2007, we began reporting the Average Time on Site as the total time on site for all visits (excluding bounces) divided by the total number of visits (excluding bounces). This change also affected data from earlier dates, not just newer data.

Because bounces have been removed from this calculation, you may notice a significant increase in the average amount of time spent on your site. Please be assured that we have in no way changed your data, only the way
that the Average Time on Site is being calculated.

I still wonder why they made this change, and also why they hadn’t reported it on their offical blog.
Anyway, it’s good knowing what this jump in numbers was all about.

Update: Google has returned to the previous policy: Bounce hits are counted as well. So now the equasion of Avg. Time on site is back to: time of all the visits divided by the total number of visits.
Thanks to Bryan for notifying me.

Posted in Web 2.0 | 8 Comments

8 Responses to “Google Analytics: Bounce Visits are excluded for Avg. Time On Site”

on 2007-07-26 at 19:081Amos

Great—thanks for the info, Yohay. This change seems strange to me, too. I wonder if there are other analytics tools that count average time on site the same way. Is GA now in-line or out-of-line with other analytics packages?
on 2007-07-26 at 20:592Yohay

Amos, I was glad to help out. I dpn’t know if disregarding bounce visits is an industry standard or not. All in all, I’m pleased with GA…
on 2007-08-05 at 22:163Will

THANKS for finding this out! I came to your site via Google. Great work, this was exceptionally helpful. Now you’ve got another reader
on 2007-08-05 at 22:324Yohay

Will, I was glad to help out!
on 2007-08-07 at 21:395baldo

cool information.. but just a question:

how the time on site is calculated?

FIRST CLICK — START TIMER — … — LAST CLICK — STOP TIMER (GA will loose the time of seeing the last page)

is that right? Or is it calculated like:

avg. time between click * number of click
on 2007-08-08 at 11:136Yohay

baldo, I think that they calculate all the time that was spent on the site, including the time after the last click. They just stopped including bounce visits in this calculation.
on 2007-08-17 at 14:047Ryan

GA does not start a timer while the person is on your website, read this for more info. http://www.detz.net/articles/google_analytics_zeros.html
on 2007-08-17 at 14:188Yohay

Thanks Ryan. I’ve read the information and it was very helpful.