Core Web Vitals

Google’s three essentials to user experience.

In 2022, UX (user experience) is being driven by one of the most powerful companies in the world. 

There are over 1.7 billion websites in the world. To find a site within this universe of possibilities we depend on search engines. Google is the most well-known, popular and powerful. To access and read/use a website, we depend on web browsers. One of the most widely used and influential browsers is Google Chrome.

In its role as a leader and organizer of the web, Google seeks to optimize their search function, their Chrome browser, and the way the web operates as a whole. They do a lot of research, which they share with developers. And they also set industry standards.

In 2020, Google revamped their algorithm to prioritize the UX over other technical criteria. Google grades websites in order to improve their own functionality and to inform their search rankings.  

The new grading priorities are: 

  • Loading performance: How quickly does a page load?
  • Responsiveness: How fast does a page respond to user input?
  • Visual stability: Do things stay in the same place on a screen?

Google calls these new “user experience criteria” Core Web Vitals. While subject to change in the future, these criteria are made up of the following three metrics.

First impressions

Largest Contentful Paint (LCP) measures the time it takes for the largest piece of content to show up on a user’s screen. This could be an image banner or text. It’s the first thing a visitor sees when visiting a site. 

Scoring well means that a site loads its initial impression in under 2.5 seconds. This type of speed signals the user that the site is functioning well. If the first image loads slowly, users often leave before interacting with content. 

Don’t make me wait

First Input Delay (FID) is another speed measurement. It tests how long it takes for a site to respond to an interaction (Google tests the first reaction). This could be a button tap on a mobile devise, or a link click or scroll on a desktop.

Scoring well means that a site reacts within 100 milliseconds or less. Responsive, quick reactions are key to keeping users engaged with content. Slow reaction times create frustration, and then abandonment by users. 

Hold still

Cumulative Layout Shift (CLS) measures the visual stability of a website. It looks at whether or not things like placement on screen, navigation buttons, content, etc., move around on a website as it’s loading­.

Scoring well is not measured in terms of time, but as a compilation of various factors. Users get frustrated when they see the content they want to access but need to wait for an image to load before a button will work or when a button moves to a different location on the screen.

Making it happen

Major content management systems (CMSs) like WordPress are constantly refining functionality issues like those measured by Core Web Vitals. If you use a CMS, consult with your developer about the most current specifications for your platform. If you’re building a site from scratch, make sure the developer is aware of these evolving conventions. From a strategic point of view, use this information to make smart choices about what content goes where to maximize UX.

UX 2022 Series 

In 2022, good UX has become the standard for good website design. In this series we look more closely at important UX features, learn how they work and how they can improve a website.

Here are other articles in this series:

UX 2022 (An introduction.)

Thumbs Up! The ergonomics of great mobile UX.

Speed: Slow websites are quickly abandoned.

Building a Green Website

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