Frontend & browser·Performance and Core Web Vitals
the dashboard shows the metric at the 75th percentile across everyone who actually loaded the page last month.
Field data
Also calledRUM, real user monitoring, CrUX
Measurements collected from real visits on real devices and networks. It is the only source that tells you what your users experience, and it is what Core Web Vitals are assessed against. It is also slow to react and hard to attribute — a regression appears days later as a shifted distribution, with no profile attached to explain it, which is why lab and field data are used together rather than as alternatives.