Flicker Effect

The flicker effect is a brief flash of the original page before a change appears in a client‑side A/B test. It happens when the browser draws the page before the test script applies the new styles or content. While usually short, it can distract users or affect measured behavior. You can reduce it with good loading practices, smaller edits, and using your site’s design system. Example: Preload the CSS for a new header style so visitors do not see it switch after the page appears.