What are Core Web Vitals?
Core Web Vitals
Core Web Vitals is an SEO term for a set of specific factors that Google algorithm considers to be very important in a webpage’s overall user experience to determine the webpage ranking on the SERP. Core Web Vitals consist three specific page speed and user interaction measurements: largest contentful paint, first input delay and cumulative layout shift.
In short, Core Web Vitals are a subset of factors that will be part of Google’s page experience score (basically, Google’s way of sizing up your page’s overall UX).
The Core Web Vitals report shows URL performance grouped by status, metric type, and URL group (groups of similar web pages). The report is based on three metrics: LCP, FID, and CLS. If a URL does not have a minimum amount of reporting data for any of these metrics, it is omitted from the report.
So these are real-world experience metrics that Google is looking at, that answer things like: How fast does the page load? How fast is it interactive? How fast is it stable? So basically, when visitors are using your web page on a mobile or a desktop device, what’s that experience like in terms of speed, how fast can they interact with it, things like that.
Now it’s joining a group of metrics that Google calls Page Experience signals. It’s not really a standalone. It’s grouped in with these Page Experience metrics that are separate from the text on the page. So these are signals like mobile friendliness, HTTPS, intrusive interstitials, which are those pop-ups that come on and appear.
It’s not so much about the text of the page, which are traditional ranking signals, but more about the user experience and what it’s like, how pleasant it is to use the page, how useful it is. These are especially important on mobile when sometimes the speed isn’t as high. So that’s what Google is measuring here. So that’s what it is.
Read more here.