A/B Testing

A/B Testing (or split testing) is when you compare two versions of something (an ad, landing page, email, whatever) to see which one performs better.

You create two variations (A and B) that differ by one specific element, show each version to a similar audience, and measure which achieves better results (higher CTR, better conversion rate, etc).

For example: two different ad headlines, same image and copy. Version A gets 1.2% CTR, Version B gets 1.8%. Version B wins. Now you know that headline works better.

This is how good advertisers systematically improve instead of guessing. Small improvements compound fast: 10% better CTR → lower CPC → lower CAC → better ROAS. Those gains stack up over time.

The most important rule: test one variable at a time. If you change the headline, image, AND CTA all at once, you won't know which change made the difference. That's the difference between A/B testing (one variable) and multivariate testing (multiple variables, needs way more traffic).

Common things to A/B test: ad creative (images/video), headlines, ad copy, CTAs, landing page layout, audience targeting, and bid strategies. It's also one of the best ways to beat creative fatigue by continuously refreshing your best-performing ads with winning variations.