While Ad Testing is a vital part of optimizing any PPC campaign, it can be tiring to track all the changes to determine what caused improvements or problems. Many agencies track everything manually in a spreadsheet, or use a bid management platform that’s geared towards bidding, not tracking. By being methodical with labels in AdWords, and using the Segment by Label option, you can have a visual key to what ad testing is happening on each ad.
Web Analytics World has a great article showing how to set this up:
The great thing about this process is that each label has an inherent ad testing goal. For example, Ad Title, Ad Content, and Ad Display URL are most typically tied to improving CTR. Ad Landing Page is related to conversion rate (CVR). Ad Offer is a combination of CTR & CVR and is probably best measured by cost per acquisition (CPA). However, although each ad category has a “natural” tie to ad performance, your goal may be different. For example, if you are trying to improve lead quality through ad content, CTR is not a good metric for ad performance. — Tracking Ad Testing in Google AdWords by Mike Nierengarten