Why the Core Web Vitals Update Matters to Publishers, and What to Do About It

What are Core Web Vitals?

The Core Web Vitals (abbreviated as CWV) are a set of metrics that Google uses to monitor page speed and the user experience.

There are three Core Web Vitals, each of which relates to a component of a user’s experience on your page:

  • Largest Contentful Paint: the time it takes for the page’s main content to load (Load Time)
  • First Input Delay: the time from when a site visitor first interacts with your site, to when the page actually responds to that command (Interaction)
  • Cumulative Layout Shift: sudden shifts or changes in a page’s layout, which can cause a user to click the wrong page element by mistake (Visual Stability)

Do note: Google has made it known that “the metrics that make up Core Web Vitals will evolve over time.”

Although the Core Web Vitals have existed for nearly a year (first introduced in spring 2020) the chatter about them — especially among publishers and advertisers — only increases as Google is set to use the CWVs to create and deploy a new ranking factor: Page Experience Signal.

(Image Source: Google Search Central)

The Core Web Vitals will combine with other site features (i.e. mobile-friendliness, safe-browsing, HTTPS security, and intrusive interstitials) to create the new ranking signal with an initial roll-out in mid-June 2021

Why are Core Web Vitals Important for Publishers?

The Core Web Vitals come together to demonstrate one critical point: websites need to realign their priorities with the end user experience. It’s why we at seoClarity refer to SEO as search experience optimization.

Since publishers tend to have a multitude of advertisements on their sites that dampen the user experience, they may find their pages do not meet the criteria to be considered “good” under the new Page Experience ranking signal.

Understanding Core Web Vitals Scores

What constitutes a “good” score for the CWVs? Just like any other metric, there are thresholds that you want to fit into.  

Google breaks down the thresholds as such:

(Image Source: Web.dev)

  • Largest Contentful Paint: should be no longer than 2.5 seconds
  • First Input Delay: no longer than 100 milliseconds
  • Cumulative Layout Shift: CLS of less than 0.1

How to Measure Core Web Vitals

You know what the CWV metrics are, and what qualifies as a good or bad score, so how do you measure your own performance?

Luckily, there are a number of tools to choose from to measure your Core Web Vital performance. Google alone offers three free tools (each of which can monitor all three CWVs):

1. Chrome User Experience Report

The Chrome User Experience Report runs on an aggregation of real user experience metrics. These users have, according to Google, opted-in to sync their browsing history, have not set up a Sync passphrase, and have usage statistic reporting enabled. 

2. PageSpeed Insights

PageSpeed Insights allows you to enter any URL and view page speed performance results for desktop or mobile. The Field Data section instantly tells you if the URL passed the Core Web Vitals assessment. This publishing site, unfortunately, does not pass the assessment:

(Image Source: PageSpeed Insights report)  

3. Search Console (Core Web Vitals Report)

If you have a Search Console account, you also have access to the CWV report. This report is based on Field Data, and grouped by status, metrics type, and URL group. 

Since it works on Field Data (i.e. real usage data) only URLs that have been indexed show in the report.  

Tip: If you use an enterprise SEO platform, it should have a page speed analysis capability that lets you monitor page speed performance

How Core Web Vitals Will Impact Publishers

Failure to provide a positive experience can absolutely hurt your organic search rankings. This of course has a relationship with traffic, clicks, and conversions. All of which can affect your bottom line if they don’t perform!

If a user does choose your site over the competition, the experience a user has on your site impacts their likelihood of staying on your site. Just look at this statistic from Google on the correlation between page load time and bounce rate:

“If page load time increases from 1 second to 3 seconds, bounce rate increases 32%”

No one wants to explore a site that has a painful user experience when so many other sites are just a click away!

To get a sense of how many sites are likely to be impacted by the update, look at this Core Web Vitals study of over 1 million websites

What Can Publishers Do?

Although the busy nature of publishing and advertising websites may make SEOs in those verticals more anxious about the update than others, there are specific actions to take to improve your site experience. 

Instead of listing off what creates a positive score, let’s look at this through the lens of what causes a poor score so you can know what needs to be addressed and avoided. 

What Affects Largest Contentful Paint?

The LCP is negatively impacted by the following:

  • Slow server response times
  • Render-blocking JavaScript
  • Slow resource load times
  • Client-side rendering 

What Affects First Input Delay?

 The FID grows in response time when there is heavy JavaScript execution. 

There are of course ways to rectify this, namely: break up long tasks, optimize for interaction readiness, use a web worker, and reduce JS execution time.  

What Affects Cumulative Layout Shift?

CLS is negatively affected by the following:

  • Images without dimensions
  • Ads, embeds, and iFrames without dimensions
  • Dynamically-injected content
  • Web fonts that cause FOIT/FOUT
  • Actions that require a network response

Other Considerations: Advertisements

Advertisements can greatly slow down a page, or cause a layout shift as the ads populate as the page loads. Be aware of where you place your ads, and how often they appear.

We’ve all experienced this layout shift on a publishing website as pop-up elements load:

Just look at how the Latest News stories drop down the page. If someone were to click a story right at the time of the layout shift, they’d click the pop-up instead. And unexpected search journeys lead to one thing: frustration!

Here are a few considerations to keep in mind when including advertisements or pop-ups on your page:

  1. Have ads load only when they are close to coming into frame. There’s no use having them load (and slowing down your site) if no one sees them.
  2. Predetermine and set your ad sizes so ad placements don’t cause a shift in the page as they populate. If the size is predetermined, the ads will fit into their allotted space correctly. 


Use the time you have left before the update is launched to optimize your site so it offers the best user experience possible. 

If you prioritize the user experience, instead of trying to outsmart the algorithm, you’ll be set up for success.

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