Mailing test groups allow you to do head-to-head testing for mailings.

They protect you from common testing errors by ensuring that the targeting is consistent, that the randomized samples are of similar sizes, that the targeted users do not overlap, and that the mailings send at the same time.

They also provide specialized reports to compare mailing performance, and the ability to click to pick the winner.

Learn more about using the mailing test group feature below: