Google’s John Mueller pointed out an important fact that I see a lot of folks in the industry misunderstanding around core web vitals. Googlebot does crawl the web and brings in most of the signals Google uses to rank your pages, but the core web vitals do not come from Googlebot or crawling, it comes from the Chrome CRuX field data report.
That means, Google uses real Chrome usage data to bring in data around the core web vitals about specific pages. That includes the LCP, FID, and CLS scores. Googlebot crawling is not the source Google is getting this data from. Chrome usage, a person visiting your site on a Chrome browser, is where Google is getting this data from.
You can learn more about the Chrome user experience report there if you want.
Here are John’s tweets:
Googlebot doesn’t evaluate the core web vitals — we use field data for that. Also, we don’t use it yet — it’s planned for the future.
— 🍌 John 🍌 (@JohnMu) April 16, 2021
Also, just because this is named “core” web vitals, it does not mean this is a core update. They are two VERY DIFFERENT things.
Forum discussion at Twitter.