This episode is a great overview of Google's new Core Web Vitals metrics that are being rolled out as part of a major update to their ranking algorithm.

I speak with Arjen Karel from the Netherlands who is a 'page speed wizard', having guided brands including Nestle, Harvard University and Erasmus to better website performance.

Core web vitals includes 3 key metrics that were introduced in Google's June algorithm update which are:

  • Largest Contentful Paint (LCP): measures loading performance. This is how fast the page renders the largest elements of your site above the fold (ie. in the visible viewport when the page loads) and can be affected by render blocking Javascript, slow server performance or poorly optimised code.
  • First Input Delay (FID): measures interactivity and the time from when a user first interacts with your site (ie. when they click a link, tap on a button) to the time when the browser is actually able to respond to that interaction. (Remember those infuriating clicks when the button doesn't appear to do anything?!)
  • Cumulative Layout Shift (CLS): measures visual stability. This is how the page layout changes and shifts around as different components load.
You can be slow by mistake, or slow by design. If you make a mistake, that's fixable. Slow by design is a design choice, and that's ok; just make sure you're faster than your competitors!

— Arjen Karel,

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