A/B Test (Split Test)
An A/B test, or split test, compares two versions of something to see which performs better. In email, you send version A to part of your list and version B to another part, changing only one thing, such as the subject line, the call to action or the send time. The winner is sent to the rest of the list or used in future emails.
Why it matters for a small business
Testing replaces guessing. Instead of arguing about which subject line sounds better, you let your customers decide. Small improvements add up over time, and testing teaches you what your audience actually responds to.
What to test
- Subject lines and preview text.
- The wording, color or placement of a button.
- Short versus long emails.
- A personal note from the owner versus a designed newsletter.
- Send day and time.
- On your website, headlines, forms and page layouts.
How to test properly
- Change one thing at a time so you know what caused the difference.
- Decide in advance what counts as winning, such as clicks or bookings, not just opens.
- Use a large enough group. With very small lists, results can be random.
- Run the test long enough to collect real data before calling a winner.
- Write down what you learned so the next email starts from it.
A real-world example
A yoga studio tests two versions of its class schedule email. Version A has a “View schedule” button. Version B has a “Book your spot for this week” button that goes straight to booking. Version B gets far more bookings. They make direct booking buttons the standard in every email after that.
Small list?
If your list is only a few hundred people, test bigger differences, like a plain personal email against a designed one, and look at results over several sends instead of one.
Related terms: Click-Through Rate, Conversion Rate, Open Rate. See our email automation and deliverability service.
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