AdWords Campaign Experiments in Google AdWords
AdWords Campaign Experiments (ACE) is a tool from Google which allows you to test real-time changes to your AdWords campaign, parallel to the current campaign. Previously, if you wanted to make changes to your campaign, you had to make the alterations and then measure them in comparison to your past results.
Using the AdWords Campaign Experiments tool you can get your ad campaign to a more efficient standard, improve your quality score and ultimately, reduce you ad spend while still maintaining a good conversion rate.
AdWords Campaign Experiments allow for simultaneous split testing of ads
ACE allows you to simultaneously split test variables within your control such as keywords, bids and ad copy, enabling a side-by-side insight into campaign performance that doesn’t involve other variables, such as seasonal traffic peaks and troughs. While traditional experimentation involves the tedious creation of more and more ad groups, the ACE tool can actually do this for you quite quickly.
There are a variety of experiments you can undertake using ACE, such as looking at the effectiveness of different match types of keywords, and the tool even allows you the degree to which you wish to control vs experiment. To learn more about the tool, just visit http://AdWords.blogspot.com/2010/06/AdWords-campaign-experiments-beta-split.html, keeping in the mind that ACE is available worldwide, not just in the US.