Core Web Vitals
Core Web Vitals are Google's measures of loading, interactivity, and visual stability. They reflect what a real visitor experiences, not what a lab machine reports.
The three metrics are Largest Contentful Paint (loading), Interaction to Next Paint (responsiveness), and Cumulative Layout Shift (stability).
Evaluate real-user field data separately from lab diagnostics. Good scores do not guarantee rankings, and a lab run alone does not establish a field-data pass.
A practical example
A banner inserted after loading pushes the article down, contributing to layout shift.
A common mistake
Calling a Lighthouse score proof that real-user Core Web Vitals passed.
How to check it
Separate CrUX field data from lab results. Use the LCP element, layout-shift records and interaction evidence to choose fixes.
Related terms
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