Google IO and Core Web Vitals ranking announcements

Google IO and Core Web Vitals ranking announcements

Google I/O is an annual developer conference held by Google. "I/O" stands for input/output, as well as the slogan "Innovation in the Open", where they typically introduce new developments.

And Core Web Vitals was one of the subjects. Although Core Web Vitals is about to be launched (mid-June), a few new updated were announced during Google I/O event. Let's do a quick recap:

Core Web Vitals coming to desktop

As always, only Google knows when, but Core Web Vitals is coming to desktop search. Like Google is using mobile Core Web Vitals results for mobile SERP's, they will be using desktop Core Web Vitals results for desktop SERP's.

How to know the difference? When using PageSpeed Insights, you'll be seeing a mobile and desktop tab navigation, like in the screenshot below:

It is quite likely that your desktop score is (way) better than your mobile score. If not, your website or webshop might be serving different HTML depending on the device your visitors are using or you might actually already be doing a great job 😜

Don't be fooled by the score though: as much as I like to achieve green and maybe even 95+ scores for at least mobile lab test, it actually is Field Data you should be looking at. Field Data is based on how real (Google Chrome) users are experiencing a webpage or domain (indicated by Origin Summary) in general.


See Google's I/O YouTube video starting at the 7:10 mark: Preparing for page experience ranking.

Ranking boost without (fully) passing Core Web Vitals

Core Web Vitals is not a binary ranking factor, is what they said. This just means the following: there is no right or wrong.

A recap of Core Web Vitals:

  • a single metric could end up in the good, moderate or poor threshold;
  • Core Web Vitals consists or three metric: LCP, FID and CLS;
  • One had to end up in the good / green threshold to pass Core Web Vitals;
  • Initially, the narrative was that you would only get a ranking boost when passing Core Web Vitals, in other words: passing all three metrics.

This changed, apparently. With the Page Experience Signal, you don't have to reach the "good" threshold for all 3 metrics to get a boost in rankings. Ranking-wise, there is no benefit in over-optimizing either after already reaching "good".

Amazon as ranking example

Let's look at the homepage of

The metrics of their homepage are as following:

  • First Contentful Paint (not a Core Web Vitals metric): 1.5 seconds, in moderate bucket due to not being within 1 second;
  • First Input Delay: 30 ms, within good thresholds of 100ms;
  • Largest Contentful Paint: 3.4 seconds, in moderate bucket due to not being within 2.5 seconds;
  • Cumulative Layout Shift: 1%, meaning within good threshold os 10%.

As part of Core Web Vitals, it's only the Largest Contentful Paint metric causing Amazon not to pass Core Web Vitals. They are passing two other metrics though and as a result might get a ranking boost already. They might actually already have a ranking boost when ending up in the moderate bucket. Do note though that the ranking boost will reach its maximum when passing all metrics.

In other words: Instead of being a binary ranking factor, it's more like a gradient ranking factor. John Muller himself loosly created a chart to visualize the potential SEO benefit.


See Google's I/O YouTube video: Web Vitals | Q&A

Google will use url, page group and origin data

When testing a URL using PageSpeed Insights, your domein would have to have a sufficient amount of visitors to even get any field data at all.

Once achieving this, you would get an Origin Summary to get an idea of the 75th percentile experiences across all pages within the same domain. If the URL you just tested had enough visitors, you would also get Field Data for the specific tested page.

This means that if you had quite some bad scoring pages, it could impact the Core Web Vitals status of pages that did not get enough visitors yet. That would be a shame if some good ranking product pages typically had a good score: those without sufficient amount of visitors could be impacted by poor scoring pages, ranking-wise.

We could have seen the following coming though: Google might try to group pages per page type. They were already doing this: grouping pages together based on template or maybe breadcrumb data.

Although it might not work bullet proof for all page types and individual pages, they will try to group pages when it comes to Core Web Vitals. So, if a few product pages have a good Core Web Vitals score, newly published products and their URL's might then benefit from the Core Web Vitals status of other product pages.