A/B testing (also called split testing) is a way of testing two different options to determine which is the most effective. When used for your email campaigns, A/B testing can help you decide which email variation will be the best one to send to your subscriber list from two different options you have created.

The idea is that you send Version A to a small, yet statistically relevant, subset of your subscribers, and Version B to another small group. The results (opens or clicks) are measured, and a winner is chosen. Then that winning version of the email is sent out to all the remaining subscribers.

Why should I use A/B testing?

A/B testing offers a simple way for you to maximize opens and clicks from your campaigns. With A/B testing you can:

• Test two subject lines, to see which one results in the most opens
• Test two completely different designs to see which one gets the best overall results
• Test an offer, eg. does a “Free Shipping” promotion do better than a “15% Off” promotion
• Test two different “from names” to see which generates the most opens

You can test and compare practically as many variables as you can think of. A/B testing is built right into most Email Service Provider (ESP) accounts, and is generally really easy to do. There are three main areas you should test. The subject line, the ‘from’ name and email address and the actual email content itself.

1) Subject line test

Taking a small subset of your recipients, say 20%, you’ll send half an email with one subject line, and the other half a different subject line. Then you can watch the results come in for a certain period. We find that 24-36 hours is plenty of time. Once you know which one performs the best, you send the email, with that winning subject line to the remaining 80% of your subscribers.

2) Email content test

In this case you create two different emails to test and send them both to a subset of your subscribers. Again the winning version is sent to the rest of your subscribers. You could have only slight design differences, or something more major, depending on what you want to test.

3) From name and from email test

In this test, the content and the subject are the same for each email, it’s only the ‘from’ name and the ‘from’ address that are different. The name and address that generates the most opens or clicks is the winner, and is sent to the rest of your list.

In order to gain the most value from testing we always ensure the variables being tested are significantly different from each other. For example when testing subject lines create two completely different ideas. In a recent example we had an email that contained two blog posts; one about a new hire and the other about the new Twitter filter. Here are the two completely different subject lines we tested:

• Are You Ready for the New Twitter Filter?
• Here We Grow Again…

In this case version B generated a 3.2% higher open rate meaning that more people found it to be interesting enough to open. We went with that subject line and enjoyed above average open rates for the rest of the campaign.

If you would like to know more about email A/B testing please leave a comment below or contact us here.