Trends & best practices

What are Core Web Vitals and how do you track them?

February 24, 2021 By: Alex Torres

Last May, Google announced that a new category called “Page Experience” would become an important factor in search engine optimization, or SEO. Google is calling this new set of categories Core Web Vitals. 

For years Google has placed a premium on websites and web applications that pay close attention to computer/human interactions. And with lots of businesses and organizations competing for the first spot on a Google search, websites with standout user experiences now have a better opportunity to pull ahead of the rest. 

At baseline, your website’s UX should be intuitive, easy to use, quick, and leave the user wanting to come back for more. 

Current SEO rankings take into account a number of factors, such as:

    • How mobile-friendly your website is, or how good it looks on a smartphone 
    • Safe browsing, which means no viruses or phishing attempts 
    • Up-to-date security certificates
    • HTTPS websites over HTTP
    • Well researched or informative content
    • Minimal pop-ups and other intrusive interstitial elements, unless they are created by a design savvy tool, like Elementor for WordPress.

These factors are known as structural components, which will remain a vital component of your website’s success. Previously, SEO has been focused on an objective analysis of the page, regardless of the value it added for users. Now SEO will be about making a nice cocktail of structure (existing SEO signals) along with perceived user benefit (Core Web Vitals).

Website performances can be negatively impacted by factors that are outside of your control, such as device capabilities, poor network conditions, and how a particular user interacts with the given page. By focusing on Core Web Vitals, however, you reduce the chance that visitors will bounce from your website.

page experience CLS FID LCP

Core Web Vitals

The 3 core vitals that Google will start measuring include Largest Contentful Paint (LCP), First Input Delay (FID), and Cumulative Layout Shift (CLS). Your website should be hitting the 75th percentile in each category across both mobile & desktop devices to stay competitive in SEO.

We know that those terms might sound scary or confusing, so we broke them down into smaller parts so you know what to expect when Google’s algorithm shifts in May 2021. 

LCP (Largest Contentful Paint)

LCP, or Largest Contentful Paint, is the time it takes for a page’s first batch of content, images, and words to load. In other words, LCP measures load speed, or how quickly a website loads in enough content to make the website look complete. 

If you’re looking to get more technical, LCP rankings depend on First Contentful Paint (FCP) and Time to First Byte (TTFB) measurements.

To boost your LCP score, you will need to speed up server response times. Accomplish this by removing render-blocking JavaScript and CSS, as well as by ensuring that image files, videos, and other visual elements are high-quality, but not too large. 

core web vitals largest contentful paint

FID (First Input Delay)

FID, or First Input Delay, attempts to quantify users’ first impression of your web page—and first impressions matter. More specifically, it measures how long it takes before the user can start interacting with the page, usually with a click. 

According to Google, this measurement “quantifies experience users feel when trying to first interact with the page.” Websites that load quickly but nonetheless exhibit high amounts of friction can suffer in this category. 

If you’re having issues with your FID score, you need to take a look at Total Blocking Time (TBT) and Time to Interactive (TTI) measurements. Be sure to reduce JavaScript file sizes, since this will help reduce the time it takes for browsers to process requests. 

CLS (Cumulative Layout Shift)

CLS, or Cumulative Layout Shift, measures how much space visual elements shift while the page is loading. In other words, it measures visual stability. 

Sudden or unexpected layout shifts lower your CLS score. This can include fonts that render larger or smaller than expected, or third-party ads that continuously resize. 

Unfortunately, CLS depends on API calls, which in turn depend on third-party tools. Your best bet is to choose your third-party integrations wisely.

In the new SEO scheme, drag-and-drop CMS platforms that take too long to resize images might see their rankings fall significantly.

Tools and Tips to Measure Core Web Vitals

Nowadays, SEO is an important part of the development process, which means that marketers and developers should work together to optimize websites and web applications. 

For an easy point in time measurement of CWVs there are tools such as Chrome User Experience Report, PageSpeed Insights, and Google Search Console (Core Web Vitals Report) can help your team ensure that their Core Web Vitals remain healthy. We expect that more third-party SEO tools like Screaming Frog will integrate SEO tools as well. 

Here’s a look at some tips for measuring your Core Web Vitals and boosting your current SEO strategy.

Gorilla Group, the commerce experience agency, explains that while Core Web Vitals are critically important, there are also some other important factors to consider in the Page Experience realm such as mobile optimization, safe browsing, and more.

Blast Analytics, a consulting and data science firm, also wrote a useful blog post summarizing how organizations should prepare for the shift in the SEO algorithm. Indeed, this might be a good time for your website to undergo an SEO audit so that your team is not surprised when May rolls around. 

BlueMoon Digital, a Denver-based digital marketing consulting firm, also has some tips for boosting your SEO ranking. Remember that Conversation Rate Optimization (CRO) and UX go hand in hand, and that a solid user experience can help to decrease shopping cart abandonment rates.


Quantum Metric now supports the measurement of Core Web Vitals! 

Experience is more than UX. Experience needs to be measured from an interaction, technical, and behavioral standpoint. Our customers love Quantum Metric because they can understand their customer experience from any level. With that in mind, adding in support for the measurement of Core Web Vitals just made sense!

You can now measure CWVs in Page Performance, compare them against network timings, build segments, and more. We will be consistently updating this functionality as time goes on and sharing some valuable insights from CWV experts in the near future, so follow Quantum Metric on LinkedIn to stay in the know.

Log into Quantum Metric today to check it out!

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