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Core Web Vitals: What Google’s 2021 Update Means

Published: November 16, 2020

Author: Hope Lee

User Experience Becomes an SEO Ranking Factor

In early May 2020, Google introduced a set of metrics related to speed, responsiveness, and visual stability to help site owners measure user experience. The new metrics are called Core Web Vitals and will be a ranking signal in May 2021. These new metrics, combined with the old page experience metrics, will create the new Page Experience ranking factor in 2021.
Graphic source: Google
Although the old metrics are not changing, the launch of the new Core Web Vitals will change how Google measures page experience. The Core Web Vitals – incorporated with mobile friendliness, safe browsing, HTTPs, and no interstitials – will impact search signals for page experience and should be prioritized for optimization. The biggest change of the new ranking signal is that Google will measure site speed by evaluating the field data gathered from Core Web Vitals. This means it will look at your website through the lens of how real users experience it.

Field Data vs. Lab Data: What’s the Difference?

Field data is a historic look-back of how a page performed for speed based on the devices and network conditions of users in the real world. These scores are updated monthly and represent the scoring of Core Web Vitals with regard to the new Page Experience ranking signal.
Lab data is a simulated load of a page on a single device with a fixed set of network conditions. Because Lab data uses a simulated environment, the results do not accurately measure how real-life users experience your page.
The results of Field data and Lab data should be similar, but there may not always be parity. When scores are present for both Lab data and Field data, you should prioritize Field data since it better reflects how real users experience the website. Lab data can help you diagnose performance issues after you’ve made website improvements.
Technical SEO Note: Test your site pages on PageSpeed Insights to compare your Lab data and Field data results. Using both sets of metrics will give you a holistic understanding of your current site performance and help you identify areas for optimization.

  • If your development team made recent updates to address performance issues, the changes will be reflected in Lab data before they show in Field data, as Field data is updated monthly.

What Are the Core Web Vitals?

Simply put, the Core Web Vitals are a set of real-world, user-centered metrics that quantify the user experience. The new Core Web Vitals focus on three aspects of the user experience: loading, interactivity, and visual stability.

Image source: Google

  • Largest Contentful Paint (LCP): Measures the time it takes for a page’s main content to load.
    • Recommendation: LCP should occur within 2.5 seconds of when the page first starts loading.
  • First Input Delay (FID): Measures the time it takes for a page to become interactive.
    • Recommendation: Pages should have a FID of less than 100 ms.
  • Cumulative Layout Shift (CLS): Measures the stability of content. This means that CLS measures any unexpected layout shifts that happens on the page.
    • Recommendation: Pages should maintain a CLS score of less than 0.1.

When Should You Begin Preparing for the New Ranking Factor?

With Core Web Vitals rollout going live in May 2021, now is a great time to plan for it. With the holidays coming up, along with likely code freezes, it’s important to be mindful of any potential resource limitations within your organization. We recommend getting resources aligned when your holiday priorities wrap up so that you’re prepared for this new Google ranking signal in 2021.
Need help keeping up with Google’s ever-changing search landscape and preparing for the Core Web Vitals update? Contact 3Q Digital to learn more about our SEO services.
You can also refer to the Google Webmaster Central Blog for more Information about the Core Web Vitals and Page Experience Update.

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