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Getting ready for Core Web Vitals

Back in November 2020, Google announced some new ‘page experience’ metrics — Core Web Vitals — which will become a ranking signal from June 2021. At iProspect, we’re tracking 1,500 sites across 15 industries to find out who’s ready, and who will miss out.

Core Web Vitals are three new metrics Google intends to use to measure the page experience of site visitors; speed (LCP); responsiveness (FID) and visual stability (CLS).

  • Largest Contentful Paint (LCP) is the time it takes for the largest piece of content to become visible on the page – whether that’s text, an image, a banner, or a video
  • First Input Delay (FID) is the reaction time of the page, after a visitor tries to do something – for example tapping a button, a link, or typing in a text box
  • Cumulative Layout Shift (CLS) measures the visual stability of a page as it renders on screen, whereby it calculates the distance all items on the page move – often because of images, pop-ups, or ad banners

From June, Google will use these metrics as a ranking signal in mobile search, which means all things being equal, pages with better Core Web Vitals scores will outrank those with poorer scores.

Ahead of the anticipated switch on, iProspect have launched a new interactive tool which monitors and tracks across 15 major industries, including eCommerce & Shopping, Automotive and Fashion, as well as comparing scores of the Top 1500 sector websites. The iProspect Core Web Vitals Evaluation Tool, shows industry trends in performance experience along with daily impact scores by sector and also for individual websites.

Our tool shows that  47% of all websites tracked are still under-performing significantly and a full 81% of sites will miss out on improved Google ranking positions come June.

Overall, less than one-in-five (19%) mobile websites will currently benefit and, evaluating the scores per industry, there is huge contrast between sectors when comparing those in good-standing for the change. The industry which is presently the least likely to benefit is Fashion, with just 4% of the websites achieving the ‘good’ grading, whereas Government sites are leading the way at 45%, closely followed by Financial Planning (29%).

Visit the iProspect Core Web Vitals Evaluation Tool here, to see the top and worst scoring sites and whether your brand will benefit from a Google ranking boost in June.


  • We’re tracking 1,500 unique sites in 15 industries (the top 100 per industry, by traffic)
  • Domain name list and industry classification are courtesy of SimilarWeb, and based on their UK data set
  • Metrics are collected daily from Google’s Chrome UX (CrUX) Report API
  • Data collected for mobile devices only, and based on the ‘origin’ (an aggregation of Core Web Vitals metrics for all pages on a site)