Chrome pre-rendering doesn’t just speed up page load times but potentially also skews web analytics

Last month the Chrome developers announced a new feature, Instant Pages, to speed up page loads after Google searches, and elsewhere on the web. I hadn’t paid much attention to it until I noticed Niall Kennedy’s comments on it and nearly choked on my morning porridge. Here’s how it works, including some detail on its impact on web analytics.

What’s going on?

When you do a search in Google using the latest versions of Chrome, the search results page can include a special header to tell Chrome to pre-load the top result pages. Chrome will then go ahead and load, in the background, those pages. It downloads the page, all the dependent stylesheets, images and JavaScript files. And executes the JavaScript. The user may or may not click through to the page.

What does this mean for web analytics?

That last bit is important. If your web analytics automatically fires on page load, it means you’ll be recording a page view when potentially the user didn’t actually see it. To fix this, Niall Kennedy suggests a fairly straightforward test to ensure your web analytics only loads when it should. Integrating this into your analytics shouldn’t be too hard, though it will require some changes. At some point it’s fairly likely that the analytics vendors will do this inside their own libraries, or at least create a standard way to do it.

[youtube http://www.youtube.com/watch?v=_Jn93FDx9oI?wmode=transparent]