A/B Testing
A/B testing is a controlled experiment in which two variants of a page or an element are shown to different user groups at the same time in order to measure which version performs better against a defined metric. Only a sufficient sample size and statistical significance allow a reliable statement about which variant genuinely performs better.
In practice
In practice, only one element is usually changed at first, a call-to-action button or the arrangement of product images for example, so that the effect remains clearly attributable. Visitors are assigned to variant A or B at random, controlled by a testing tool or your own scripts, while GA4 or a separate analytics tool measures the target metric. A common mistake is stopping a test too early, before enough data has accumulated for a robust result.