Google may or may not use the Core Web Vitals metrics from pages not within Google’s indexed, pages you may explicitly block from indexing, as part of its overall calculation for the upcoming Google Page Experience Update. John Mueller of Google said he believes this to be the case but is not 100% sure.

John later explained on Twitter the rational for this, saying “user-experience is based on more than just the initial landing page in many cases. The product / shop / checkout example fits well there. Often people go to websites, they don’t just go to an individual page. It’s not always clear & easy though.”

In short, once a user goes to a specific page through search that is indexed, if the other pages they click on are slow or a poor user experience, then is that a good thing?

But honestly, Google never really worked that way. If you noindex a specific page, Google probably should not count that page against you in how the other indexed pages are ranked. It is just how Google has always operated. If I had a vote, I’d say Google should ignore pages that are not within Google’s index for any ranking values around the upcoming Page Experience Update.

Here is the video where John said this at 47:45 minutes into the video:

Here is the transcript:

Here is John’s later tweet on this:

Forum discussion at Twitter.

Update: This is no longer true, Google in 2022 stopped using noindexed pages in core web vitals.