Layout Shift

Definitions

1. An unexpected movement of visible page elements after they have already been rendered, measured by Cumulative Layout Shift (CLS) as a Core Web Vital. Common causes include images without dimensions, dynamically injected ads, and late-loading web fonts.

   In plain English: When content on a webpage jumps around as it loads, causing you to accidentally click the wrong thing.

   Example: "Users kept clicking the wrong button because an ad banner loaded and caused a massive layout shift right as they tapped."

Related Terms

• Wireframe
• Mockup
• Prototype
• Persona
• Information Architecture
• User Flow
• Usability Testing
• Performance Budget