What is the Facebook Learning Phase? [2020 Update]

By Tinuiti Team

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 stable 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.

Ad sets exit the learning phase as soon as their performance stabilizes. Typically, performance stabilizes after an ad set receives around 50 optimization events within a 7-day period.

If seven days have elapsed since a significant edit and an ad set has still not exited the learning phase, the Delivery column reads “Learning Limited.”
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.

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


    Manual optimizations (edits) are a leading contributor to ad sets not exiting the learning phase. Certain campaign, ad set and ad edits reset the learning phase.

    These are the edits that will cause an ad set to reenter the learning phase:


    – Budget (depending on magnitude)
    – Bid amount (depending on magnitude)
    – Bid strategy


    – Any change

    Ad sets:

    – Targeting
    – Placement
    – Optimization event
    – Adding new creative
    – Bid strategy
    – Bid amount (depending on magnitude)
    – Budget (depending on magnitude)
    – Pausing for over 7 days

    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.

    Why the Learning Phase Matters

    “The learning phase is valuable because the system is actively exploring different delivery options (such as, time of day, placement, audiences, etc) to understand where to get the best result for the most efficient cost. With that, there will be some less efficient delivery as the system is learning what and what does not work. We want to exit this phase as quickly as possible in order to drive the most efficient performance.”

    –   Lize Keefer, Specialist, Paid Social at Tinuiti

    Elizabeth Keefer Paid Social Specialist at Tinuiti


    According to Facebook, during the learning phase, ad delivery has not yet optimized, so ad sets in the learning phase are less stable and usually have higher CPA. These graphs illustrate the impact of learning phase on CPA.*

    A smaller share of budget spent in the learning phase typically results in a higher share of budget spent on stable performance and lower CPA. Advertisers with ~20% of spend in the learning phase (2nd decile) see 17% more conversions and 15% lower CPA than advertisers with ~80% of spend in the learning phase (6th decile).*

    Credit: Facebook Business

    “Every time new assets are launched or an edit is made to the campaign an ad enters the learning phase. In order to exit the learning phase we typically see performance stabilize once an ad set received 50 optimization events within a week. While we want to prioritize testing and learning with our clients to ensure we’re constantly evolving the program, we also want to reduce CPA and drive the highest amount of conversions by allowing performance to stabilize and deliver efficiently,” Keefer says.

    According to Keefer, it is considered a best practice is to have a smaller percentage of budget spent during the learning phase since advertisers typically see higher CPAs and less stable performance during this period.

    “Making smaller more meaningful adjustments to ads (edits, copy changes, targeting adjustments) about 1x per week rather than every day, can ensure more efficient delivery since the majority of spend won’t be pushed into learning. As a best practice to optimize performance, less than 20% of your budget should be spent in the learning phase.”


    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.


    You Might Be Interested In

    *By submitting your Email Address, you are agreeing to all conditions of our Privacy Policy.