The AdWords Campaign Experiment (ACE) is a new free tool that Google rolled out just last week to the U.S. market. The tool allows you to test and measure changes to your keywords, ad groups, bids and placements.

ACE allows you to experiment with multiple campaigns simultaneously through split tests.

Pre-ACE days, an advertiser would compare key metrics by looking at the previous week’s/month’s data after making changes to a campaign. However, when doing this, you couldn’t really be sure if changes in your campaign were the result of the tweaks you had just made, or if it had to do with other external factors, like seasonality, shifts in demand, competition etc. But now, with ACE, you can experiment with campaigns simultaneously through split tests, allowing you to measure results easily and efficiently. The ACE test also allows you to run shorter tests without having to be concerned about external factors (i.e. seasonality) that may influence your results.

Over the course of the next few weeks, you’ll be able to find the ACE tool in AdWords under “Campaign Settings.” Google has also added a new parameter, “ValueTrack parameter” {aceid} that allows your tracking system to identify if a click came from the control or the experiment part of your campaign. This’ll make it easier for you to compare and understand the impact of the experiment.

And why is this so cool? Well, if you’re constantly testing new pages or user experiences, for example, ACE will be an easy way to determine what’s working and not working in your campaigns. Plus, you’ll no longer have to assume why a particular change occurred – simply pull the readily available stats to find out exactly what happened. Definitely exciting news from Google!