Helen Schindler, AdWords Crew at Google, announced that AdWords Campaign Experiments rolled out to all US advertisers this month. This is a “free tool that makes it easier to test and precisely measure the impact of changes to your keywords, bids, ad groups, and placements,” stated Schindler.
According to Schindler, advertisers most likely waited 2-4 weeks before after making campaign changes to evaluate their optimization efforts prior to using this tool. This tool allows campaign experiments to run “side-by-side” with the original campaign in a split test; enabling advertisers to run tests quicker and control the duration of each test. In addition, Schindler stated that “you get more precise impact estimates and more chances throughout the year to test and improve performance.” (via Google)