Google pre-rendering in Chrome 13 – an analytics nightmare

The recent launch of Chrome 13 (auto updates means you might already have it) is causing some problems with onsite analytics.

If you assume that when a page is called and the referring server is Google then most analytics packages will register that as a Visit. This functionality they call is “Pre-rendering”. I guess a clue is in the name!

This is what we have seen recently. You may not of noticed yet. You should check. If Chrome represents 5 to 15% of your users browsers and your SEO accounts for 15 to 50% of your traffic. You might just be celebrating a small but steady growth in SEO visits.

As Chromes popularity increases this will become more obvious. And if you are taking credit for visit growth, you may have some back tracking to do publicly in due course.


  • Your conversion rate is decreasing from your SEO traffic
  • That your single page visits and ‘bounce-rate’ is increasing

And, if you look at the browser profile of those two things and you may find your smokin’ gun.

How does it work?

If you have a plugin such as Firebug, activate it.  Open a Google SERPs and when you hover over the magnifying glass, watch the code actually change in its open connection.  You will see that it actually calls the page. And there lies your analytical headache.

What can you do about it?

  1. Understand if your analytics are affected by this. If not, you are lucky.
  2. You may need to update your tracking code on the site to accommodate this new behaviour
  3. Do some proactive explaining to your stakeholders

The cynical part of me may suggest that Google trying to be more relvant to users and speeding up their experience, may have a happy byproduct of disrupting all analytics providers that arent theirs !

References and notes

A big thank you to Jason Moorman who works in the analytics team who has done so much of the heavy lifting in this investigation which lead to this discovery.

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