Right now, campaign drafts and experiments in AdWords are now available for those campaigns that run on the Google Display Network.
Users will be able to see the Drafts box next to the date range in the upper right corner when you’ve selected a display campaign. Clicking on this butting will bring up the dialogue box that shows the steps to get started.
Campaign drafts and experiments will be used to test changes to your campaigns, like strategies and bid adjustments, and it won’t affect performance. When in drafts, you will basically make a mirror campaign in which to make your changes. Any changes made to this draft can be applied to the active campaign, deleted or executed as an experiment to test how the changes will perform against the main campaign being mirrored by designating a portion of the budget to the experiment for a period of time.