TL;DR
Field data is performance measurement collected from real users in real conditions, while lab data is collected in a controlled synthetic environment with a fixed device and network profile.
What is Field Data vs Lab Data?
Field data is performance measurement collected from real users in real conditions, while lab data is collected in a controlled synthetic environment with a fixed device and network profile.
Learn more in our lab vs field data in practice guide, or work with us through our done-for-you speed optimization service.
How Field Data vs Lab Data is Measured
Field data is available from CrUX and real-user monitoring tools. Lab data is produced by Lighthouse, WebPageTest, and Chrome DevTools.