The A/B Split Test enables you to improve your campaign's efficiency. Test 2 versions of a message on a sample selection of your database, then send the winning message to the rest.
Test the sender, the subject line and even the content of the email
Improve the efficiency of your email campaigns
When the box is checked, another step appears in the left-hand menu that says "A/B Split".
The A/B split may test the sender field, the subject, or the email itself (sender+subject+content). You may also configure the size of the samples to test and how you want to determine the winner.