Why A/B Testing Facebook Ads Is A Necessity

Facebook advertising can be tricky and a lot of the time (especially when you’ve just started running Facebook ads) it can be a guessing game to know which ads and audiences to use. This is where Facebook A/B testing or split testing comes in handy…

What is Facebook A/B Testing?

Facebook A/B testing is a marketing strategy where two parts of the Facebook campaign are tested against each other to analyse which one delivers the best results.

Facebook ads can be split up to five times which also helps to ensure that your audience only sees one variation of your ad for the duration of the test.

For example, you can test the same ad on two different audiences to see which ad performed better. Or, you can test two different forms of creative to determine which is more effective.

How Does Facebook Split Testing Work?

Firstly, your audience will be broken down into random, non overlapping groups. This makes sure the test is fair and the results aren’t skewed by people seeing all ads in the test.

Each group will receive ad sets that are identical, apart from the variable you are testing (we’ll look at these in more detail later). These include:

  • Creative
  • Delivery optimisation
  • Audience
  • Placement

Each ad set’s performance will be measured against your campaign objective and the one which performs the best will ‘win’ the split test.

After the test is complete, you will be notified of the winning strategy. These insights can then fuel your ad strategy and help you design your next campaign.

When Should You Carry Out a Facebook A/B Test?

There are numerous reasons why you may want to run a Facebook split test, including:

  • Finding which images, videos, text, CTAs work better.
  • Finding what type of audience engages with your ads the most.
  • Discover which placements or platforms your ads perform best.
  • To find out which combination of ad achieves your business goals. For example, you could run a series of split tests to find out which image works best for a particular audience

Facebook A/B Testing Best Practices

Using the following best practices will help you gain conclusive results for your split test:

  • Only test one variable at a time, so you can ensure only one factor has determined the difference in results.
  • Give your test enough time to statistically determine a ‘winner’. Facebook recommends between 3 and 14 days.
  • Allow enough budget to gain sufficient and meaningful data
  • Use a large audience to support the test and don’t use an audience that is being used in another campaign at the same time. Having overlapping audiences can cause ad delivery problems.

What Can You Test in a Facebook A/B Test?

You can split test a variety of aspects of your Facebook Ads, including:

Facebook campaign objectives:

  • Traffic
  • App installs
  • Lead generation
  • Conversions
  • Video views
  • Catalogue sales
  • Reach
  • Engagement
  • Messages
  • Brand awareness

Selecting a variable for your split test:

When you have chosen the Facebook campaign objective that you are going to run for the split test, you can then choose which variable to test. These could be:

1. Audience

When running any Facebook campaign, you need to know who your target audience is. Split testing who sees your ads is a great way to understand what type of people are more likely to engage with your ads and convert. As a result, you will find your ‘ideal audience’.

Facebook will randomly divide your audience at the ad set level to make sure the test is conducted fairly and to give each ad an equal chance in the auction.

Example audience split tests:

  • Females living in Stafford Vs females living in Birmingham
  • Ages 25-35 Vs ages 35-45
  • Custom lookalike audience Vs interest based targeting

Audience creation tips:

  • Your audience needs to be large enough to support the test
  • Don’t use test audiences in other live campaigns as this could have an impact on results
  • Only test one type of audience against each other

2. Creative

Testing different ad creatives helps you understand what images, videos, text, headlines and CTAs perform better. To split test your Facebook ad creative, you need to create two or more variations of the ad, this could be testing an image against a video or changing the ad copy.

You are able to create two and five different versions of your ad.

Ad creative split test ideas:

  • Different CTAs – testing a direct CTA button such as “Shop Now” or “Send Message” against a CTA in the ad copy
  • Images against videos – single images against single videos
  • Headlines – one headline compared to two
  • Ad copy – short ad copy Vs customer testimonial

3. Placements

By testing different placements, you can get a better understanding of what platforms your ads perform best and where to show them on those platforms e.g. Stories or feeds.

Be careful when selecting placements as limiting placements can have a negative effect on ad delivery. Therefore, it’s recommended to use as many placements as possible.

Example split test placement ideas:

  • Automated placements Vs customised placements
  • Mobile placements Vs desktop placements

4. Delivery Optimisation

Testing optimisation events can make all the difference in how well your ad performs. For example, you can optmise your ad for landing page views or link clinks to see which one leads to better results.

Example ad delivery tests could be:

  • Testing optimised for conversions Vs link clicks
  • Ad set optimised for conversions with a 1-day-post-click conversion window Vs a 7-day-post-click conversion window
  • Testing optimised for landing page views Vs link clicks

How To Set Up A Facebook Split Test

Setting up a Facebook split test is fairly straightforward and Facebook does all the hard work for you, all you need to do is specify what variables you would like to test and sit back and watch the data roll in.

  1. To get started, you will need to set up a new campaign from the list of campaign objectives as normal. We’ll choose a ‘Traffic’ campaign as we would like to encourage more people to visit our website.

2. After selecting your campaign objective, you need to enable the split testing option “A/B test your creative, placement, audience and delivery optimisation strategies”  and choose which variable you wish to test. In this case, we’ll choose testing the creative to see if this affects how many people visit our website.

3. Now, set up your placements, delivery method and audience.

4. In the Split Test Budget & Schedule option, you can enter your budget. Remember to allocate a sufficient amount of budget to the split test so you can gather meaningful results. If you’re not sure of what your budget should be, Facebook provides budget recommendations, so you can go always choose this option.

5. Next, select when you would like to run your split test. You can start it straight away or schedule a start and end date/time. When choosing the duration of your split test, remember to allow enough time to gather enough data. Facebook recommends between 3 and 14 days as sufficient time.

6. Once the budget and schedule is set up, you can now move onto uploading your creative for the A/B Facebook test for the first ad set – ad set A. Once uploaded, repeat for ad set B.

7. Select Publish and your test will start on the date you specified.


When the Facebook split test is over, you’ll get an email and notification with the results, but you can also view them in Ads Manager as normal. When reviewing your results, there are several key components to understand how your ad sets performed:

Winning Ad Set

The winning ad set is the ad set that performed best.

The winning ad set is decided by comparing the cost per result of each ad set or ad based on your campaign objective. Based on the data from the test, Facebook simulates the performance of each variable tens of thousands of times to determine how often the winning outcome would have won.

Confidence Level

At the end of the test, you are also given a confidence level, which represents how likely it is that you’d get the same results if you ran the test again.

For any split test, a confidence level above 75% indicates that you should use the winning ad set.

Once you’ve interpreted your results, you’ll hopefully have a better understanding of what variable works best for your audience and have the ability to use these results for future campaigns. Your next steps could be:

  • Create a new ad from the winning ad set right from the results email.
  • Reactivate the winning ad set in Ads Manager.
  • Create a new campaign based on what you learned.

If your results have a low confidence level, you can test the campaign again with a longer schedule or higher budget. More time and budget typically produces more information, which helps Facebook determine the confidence level.


Facebook Ads are an ever-growing and evolving social media marketing feature that you can’t afford to miss out on. Use our tips and tricks to boost your social strategy and start improving engagement rates, building brand awareness, driving traffic to your website and generating sales.

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