Sometimes you just aren’t sure which subject line will perform best. And sometimes you’re just sure that a subject line will reel in your audience. Using an A/B split test on two subject lines is one way to confirm your choice using hard data.

Lexington Podiatry learned the value of the A/B split test on a recent holiday sale email campaign, where they tested two subject lines:

A: Save 20, 15, 10% – see details

B: Shop SOON, Save MORE!

The results were a surprise. Subject line B was the winner with 9.98% open rate compared to 9.5% for subject line A. 

“We were just sure that the 20%, 15%, 10% – see details was going to be a more customer-centric subject line, but the mysterious immediacy of the Shop SOON, save MORE subject line was more intriguing to the patient,” says Elise Hinchman, Marketing Director at Lexington Podiatry. “Combine that with the fact that some of the % off subject line emails may have landed square in the spam filter, I’m glad we ended up relying on data driven results and not our incorrect hunches.”

The lesson: It never hurts to run an A/B split test, even when you’re confident about your subject line. The results just may surprise you!