Have you ever experienced performance fluctuations shortly after the launch of a new Facebook advertising campaign (or after making edits to an existing campaign)?

It might not be a fluke and you could be experiencing a data collection period known as the “Facebook Learning Phase“.

The good news is – this testing phase is pretty standard (especially for new campaigns) and once Facebook has collected enough data about your campaign, it will start delivering your ads more stably.

In the following post, we explain exactly how the Learning Phase impacts your Facebook campaigns and what you can expect in terms of a timeline.

What is the Facebook Learning Phase?

Facebook learning phase

According to Facebook:

When we start delivering your ad set, whether at the start of a campaign or after you edit it, we don’t have all the data necessary to deliver it as stably as possible. In order to get that data, we have to show ads to different types of people to learn who is most likely to get you optimization events. This process is called the “learning phase.”

Once Facebook has gathered all the data they need – your campaign should experience fewer performance fluctuations.

How Long Does the Learning Phase last?

According to Facebook, during the Learning Phase you can expect more performance fluctuations than usual.

Pro-Tip: It is recommended that you do not make any significant edits to your ad set during the learning phase because doing so may trigger the learning phase to reset before generating enough meaningful data.

Allowing Facebook enough time to gather data about your campaign is critical. Keep in mind, delivery will get more stable as Facebook continues to collect data – even beyond the learning phase.

In terms of how long the Learning Phase will last, your ad set needs to get about 50 optimization events after starting to run or since the last significant edit to complete the learning phase.


An optimization event is defined as the number of times your ads achieved the outcome your ad set is currently optimized for, based on your chosen conversion window. This metric is calculated as the number of optimized events that occurred during your chosen conversion window.

Keep in mind:

  • 50 optimizations is an “estimate”:  According to Facebook, 50 optimization events is their general guidance, but the actual number required by any given ad set could vary based on its specific characteristics and/or the market conditions at the time it’s running.
  • Don’t forget about your “conversion window”: If your optimization event is conversions, you need to factor in your conversion window too.

Facebook provides the following example: If your conversion window is 7-day click, the 50 or so conversions you need all have to happen within 7 days of the click that led to them.

This means ad sets with longer conversion windows may need more time to complete the learning phase, since they’re likely promoting products or services that have longer consideration times.

What qualifies as an “edit” that could trigger the Learning Phase to restart?

Although is it not recommended to make edits during the initial data collection process, not every edit is considered significant enough to reset the Learning Phase.

Below is a list of all the significant edits, which will reset the learning phase:

  • Any change to targeting
  • Any change to ad creative
  • Any change to optimization event
  • Pausing your ad set (or the campaign it’s in) for 7 days or longer (the learning phase will reset once you un-pause the ad set or campaign)
  • Adding a new ad to your ad set


Depending on the magnitude of the change, making adjustments to the Bid cap,  target cost, or Budget amount may or may not trigger the Learning Phase to restart.

Use common sense on this one – for example, if you increase your budget from $200 to $201, that isn’t likely to reset the learning phase. However, if you change your budget from $200 to $2000, that may reset the learning phase.

What if my campaign never reaches the 50 optimization events threshold?

If your ad set doesn’t get 50 optimization events within a certain time period, Facebook may choose to remove your ad set from the Learning phase automatically.

According to Facebook, this can happen if your ad set’s optimization event is too rare (doesn’t occur the minimum number of times) or if your ad set isn’t competitive enough in the auction.

If this happens, it is recommended that you:


What can I do after the Learning Phase?

Once the learning phase has ended, you can use the available data to make an informed decision about your ad set.

  • If you’re satisfied with your results, you can let it keep running or increase its budget.
  • If you’re unsatisfied, you can edit the ad set to try to improve its performance, or pause it

For more on the Learning Phase, email tara@cpcstrategy.com

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