Updated: Dec 5, 2017
How Facebook Split Testing works
Facebook's Split Testing feature allows advertisers to create multiple ad sets and test them against each other to see what strategies produce the best results. Here's how it works:
Split Testing divides your audience into random, non-overlapping groups who are shown ad sets with identical creative.
This randomization helps ensure the test is conducted fairly because other factors won't skew the results of the group comparison. It also ensures each ad set is given an equal chance in the auction.
Each ad set tested has one distinct difference, called a variable. Your variable can be different audience types, placements, or delivery optimizations. Facebook will duplicate your ads and only change the one variable you choose.
To get the most accurate results from Split Testing, you'll only have the opportunity to test one variable at a time. For example, if you test two different audiences against each other, you can't also test two delivery optimizations simultaneously because you wouldn't know for sure which change affected the performance.
Split Testing is based on people, not cookies, and gathers results across multiple devices.
The performance of each ad set is measured according to your campaign objective and is then recorded and compared. The best performing ad set wins.
After the test is complete, you'll get a notification and email containing results. These insights can then fuel your ad strategy and help you design your next campaign.