Web Vitals lab data refers to Core Web Vitals performance measurements generated through simulated testing tools, like Lighthouse, under controlled, consistent conditions, rather than reflecting real-world visitor experiences.
Lab data is particularly useful during development and testing, since it provides immediate, consistent, and reproducible performance feedback, allowing developers to test the impact of specific changes before they affect real users.
Because lab data doesn’t reflect the variability of real-world devices and networks, it should be used alongside field data for a complete performance picture, rather than relied upon exclusively for SEO evaluation.
We use both lab and field data together within our Technical SEO service.