As you know, we now know the Google Page Experience Update is coming in May 2021. But don't try to fool or trick the metrics, specifically the iFrame loophole. Google's Addy Osmani said that the Chrome UX report does account for iframe content.
There is this loophole to put your stuff that doesn't score well with the core web vitals in an iFrame so Google doesn't see it. But that won't work said Addy Osamni the Chrome UX report, which is what Google will use for its Page Experience Update. He did say that the Lighthouse and DevTools currently do not and those tools need to be adjusted so webmasters and developers using it can better debug for the issues.
Here are pieces of this conversation from Twitter:
Can you link to details please? In general the web vitals are designed to accurately represent specific aspects of the user experience and not be influenced by implementation choices invisible to users.
— Rick Byers (@RickByers) November 10, 2020
Right. There's a security restriction in the RUM API here, but I'm not aware of any reason that must impact Lighthouse, so maybe a bug? @addyosmani @egsweeny.
— Rick Byers (@RickByers) November 10, 2020
CrUX and so PSI RUM data do take iframes into account, and that should be taken as the gold standard.
As Rick notes @ChromeUXReport does account for iframe content, however Lighthouse and DevTools currently do not. Addressing this bug is on our radar and we're evaluating matching CrUX behavior (e.g LCP handling frame trees, CLS considering shifts from all frames) for consistency
— Addy Osmani (@addyosmani) November 10, 2020
Thank you Nathan for notifying me of this.
Forum discussion at Twitter.
