What is A/B Testing?

A/B testing is a method of comparing two versions of something to determine which one performs better. That’s the first definition in the startup dictionary, and one of the most useful.

How does A/B testing work?

Here’s what it looks like in practice. You write two headlines. Half your visitors see version A. Half see version B. You measure clicks, signups, or sales. The winner stays.

Why does A/B testing matter?

Founders skip this because they trust their gut. Fair, but your gut wrote version A. The data decides if it was right.

Where did A/B testing come from?

The method is older than the internet. Direct mail marketers split their lists for decades to see which envelope got opened. Google famously tested 41 shades of blue on a single toolbar link. The winning blue reportedly added $200 million a year in ad revenue.

How do you run a good A/B test?

Three rules keep a test honest. Change one variable at a time. Run the test long enough to trust the result. Ship the winner, then test the next thing.

You don’t need fancy tools to start. One email subject line, two versions, half your list each. That’s a real A/B test.

Bottom line: opinions are cheap, and traffic tells the truth. Pick one thing and test it this week.

For more startup terminology, visit startupdefinitions.com.