When running an Adwords campaign ongoing testing is an essential process to continuously improve performance. In the past A / B testing has only been possible by manually running combinations of changes over different time periods. This process is inherently flawed by the fact that it was impossible to completely attribute differences in campaign performance to the changes made, as they could also be a result of seasonal and industry fluctuations. Google explains this flaw with the following example:
“Let’s say you’re advertising soccer balls, and you decide to increase your bids to get more traffic. Two days later, the World Cup starts, and your clicks and impressions increase substantially. If you had simply raised the bids in your campaign without running an experiment, you wouldn’t know how much of the increase in traffic is due to the World Cup, and how much is a result of you increasing bids.”
With the launch of Adwords Campaign Experiments (ACE) it is now possible to run simultaneous split tests by systematically dividing the traffic over a time period between your control group and your experiment group. This means that the changes can be fully analysed before they are applied to the rest of the campaign. The experiment can be set up to receive between 10 – 90% of the traffic, in turn dramatically lowering the risk of the change having an adverse effect on the entire campaign.
Limitations of campaign experiments
1) It is not possible to either enable or disable a feature at the campaign level, the campaign settings apply to the entire campaign which means both the experiment and the control.
2) You cannot use experiments on campaigns where automatic bidding is being used as this feature sets the max CPC bids for you.
3) The new Enhanced CPC feature which is currently in Beta stage cannot be enabled when running an experiment.
For more information on this new feature check out this short video.