Site Performance: About Core Web Vitals

3 min read
Google has announced that as of May 2021, they have added three new metrics to their Google Search Ranking, called Core Web Vitals. These metrics measure aspects such as load time, interactivity, and visual stability, and can be found under the Enhancements tab in Google Search Console. 
In this article, learn more about:

Why are Core Web Vitals important?

Core Web Vitals are important as they measure your site's performance with data from real world usage and visitor experience, as well as lab data from simulated sessions. They display how your site is currently performing, and can provide insights on areas that may need improvement. 
The three Core Web Vitals currently in use by Google are as follows:
  • Largest Contentful Paint (LCP): An indication of a site's loading time - more specifically, how long it takes for the largest content element in the site's viewport to load.
  • First Input Delay (FID): The time it takes for the site to respond after a visitor interacts with it (clicks a link or button, etc.).
  • Cumulative Layout Shift (CLS): A measurement of unexpected movements of elements that change the layout of the page.
These vitals, along with other measurements, will accumulate to provide an overall score for your site's pages.

Viewing your Core Web Vitals report

Core Web Vitals are included as a displayed metric in both PageSpeed Insights and Lighthouse reports. However, to view them as a separate report, simply open them with your Google Search Console.

The difference between mobile and desktop scores

When you run a URL through Google Search Console, or through PageSpeed Insights, you will be shown two separate reports - mobile and desktop. It is likely that the two overall scores will be different.
Mobile scores differing from desktop is normal. There are a few factors that contribute to this, some of which are:
  • Mobile devices generally have slower processors than desktops.
  • Mobile devices need to resize images and site elements to fit the viewport.
  • PageSpeed Insights calculates the mobile site loading time with a simulated 3G connection on a low-end device.

How will this affect my SEO?

Although Core Web Vitals are an important indication of your site's performance, they are one of the many measurements used to determine your site's SEO ranking. 
Content will remain the most important factor in maintaining your SEO score. We recommend optimizing your site's content, as well as updating your page's meta tags. Learn More
If you choose to run Google Lighthouse performance audits, we advise using an incognito / private mode browser, as regular browsers with extensions can negatively impact your score. Extensions will not affect PageSpeed Insights scores, and these can be run on a regular browsers.

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