After you buy your campaign, ads will begin to be generated. As time passes, our system will go through something called the “Learning Phase,” where it learns more about the best people and places to show the ad. The more an ad is shown, the better the delivery system becomes at optimizing the ad's performance. During the learning phase, the delivery system is exploring the best way to deliver your ad set - so performance is less stable and cost-per-action (CPA) is usually worse. The learning phase occurs when you create a new ad or ad set or make a significant edit to an existing one.
To avoid behaviors that prevent ad sets from exiting the learning phase, we recommend you:
Wait to edit your ad set until it's out of the learning phase. During the learning phase, performance is less stable, so your results aren't always indicative of future performance. By editing an ad, ad set or campaign during the learning phase, you reset learning and delay our delivery system's ability to optimize.
The learning phase is necessary to help the delivery system best optimize ads, so you shouldn't try to avoid the learning phase completely. Testing new creative and marketing strategies is essential for improving your performance over time.