7 WINNING A/B TESTS THAT FEEL ILLEGAL TO KNOW

Summary from the TLDR Marketing newsletter

A 4-year study of 150,000 A/B tests showed that most optimizations fail, with clarity consistently outperforming conventional best practices. Companies like Brex improved conversion by removing trust-building elements like customer logos, which unintentionally caused doubt or distraction. Direct copy, single-message layouts, and simpler user journeys were more effective than emotional appeals or social proof. The study found that eliminating or reducing carousels and using neutral phrasing on CTAs drove better results.