Ultimate Guide to Core Web Vitals for Publishers

Brock Munro
January 8, 2021
March 20, 2024
Ultimate Guide to Core Web Vitals for Publishers

Core web vitals for publishers

Core Web Vitals are a major ranking factor for search engines. As an ad publisher, it has become increasingly important for you to not only learn about core web vitals (CWV), but also why they’ve become so significant in terms of user experience.

If you don’t already know, Google has officially declared that Core Web Vitals will be a ranking factor in mid-June 2021, which is only weeks away. Before we delve into any further details, let’s dive into the fundamentals to develop a basic understanding.

Google Core Web Vitals announcement

What are Core Web Vitals? The Three Core Web Vitals

When Google talks about the Core Web Vitals, it is referring to three basic metrics that determine the quality of user experience in the real world. What it means is that, instead of taking only a variety of benchmarks into consideration, Google is now preparing to factor in real-world performance and user experience provided by the website to determine its ranking. The three metrics include the following:

1. Loading times

The first factor that Google will take into account is the loading time of the website i.e. how quickly the written and visual content loads on the page (ie. page load speed).

According to a report published by Google, if load time of a page increases from 1 to 3 seconds, bounce rate jumps 32%, while if page load time increases to 6 seconds, the same bounce rate witnesses an overwhelming increase of 106%.

2. Input performance

The second and one of the most important factors measures the input delay, which helps to determine the quality of user experience on the website. It also provides a measure of how the website reacts to the user input.

3. Visual stability

This is the third metric in which search engines measures the ability of a diverse range of visual elements present on the page of the site to move around, while it’s loading without causing any experiential interruptions or issues.

In technical terms, the above three metrics will be known as:


Let’s find out what these terms actually mean and what you can do to optimize your site for these metrics, so it has a better chance of securing higher search rankings.

Largest Contentful Paint (LCP)

Largest Contentful Paint, or LCP, assesses the loading time or performance of the elements present on the website. In easier words, it determines the overall duration of the largest web element, whether it’s an image or content, to show up on the screen.

To deliver exceptional page experience, according to Google’s Core Web Vitals Status definitions, Largest Contentful Paint (LCP) must be kept below 2.5 seconds while a report by Kissmetrics suggests 47% of all visitors expect the loading time to be less than 2 seconds.

Google Core Web Vitals largest contentful paint (LCP)

You can measure the page loading time for the largest web element on your website to determine the largest contentful paint performance.

First Input Delay (FID)

First Input Delay determines the loading performance or responsiveness of the website or its pages. It measures the time from when the visitor interacts with your website.

For example, by clicking a call-to-action (CTA) button, to the time it takes for the browser to respond to that generated request. To deliver exceptional page experience, First Input Delay must not exceed 100 milliseconds or your website could be penalized.

First Input Delay (FID)

Once again, you can measure the first input delay of different web elements on your website to find out whether it needs improvement and are optimized enough for search engines.

Cumulative Layout Shift (CLS)

This metric measures the amount of visual stability and unexpected shifts in a website’s page layout. The shift is deemed to have occurred when a visible element modifies its initial position between the frames. These unstable elements have a negative impact on user experience, so in order to provide a good user experience, your web pages must maintain a CLS value of under 0.1.

Google Core Web Vitals cumulative layout shift (CLS)

Keep in mind that cumulative layout shift only involves the existing elements that change their initial position. If there is a new element being added to the web page or an existing element modifies its size, it’s not considered as a layout shift unless its initial position has changed.

Why are Core Web Vitals important?

A post published in Google Webmasters Central Blog stressed on improving the importance of page experience to create a better web. Google has already factored in mobile-friendliness as well as page load times in its experience criteria and its Chrome team has now announced CWVs to be the next measure of user experience.

As mentioned earlier, these metrics measure the responsiveness, visual stability, and load speed of web pages enabling brands and businesses to analyze and optimize their website experiences.

It also gives Google’s algorithm new metrics to evaluate visitor experience and rank websites accordingly.

Core Web Vitals have become increasingly important because:

  • Businesses need to deliver consistent web experience across a multitude of devices
  • They help businesses build a better web experience for their visitors and customers
  • They provide search engines with new metrics to evaluate web page performance and overall experience
  • They allow both businesses and search engines to drive better user engagement

When will Core Web Vitals become a search ranking factor?

As the COVID-19 pandemic continues to have an impact on the business world, Google has pushed back the release of this major algorithm update as they want to give more time to webmasters to prepare for the update.

That being said, it is predicted to happen sometime in the first half of 2021 around Spring 2021 at the earliest.

Google has promised that they will give at least 6 months of prior notice to webmasters and SEO professionals to prepare for this major update.

So far there hasn’t been any notice issued by the search engine giant, but it could be around the corner, so website owners need to be on their toes in terms of preparing for the update.

Regardless of the when Google decides to implement the algorithm changes, we believe that site owners should already be improving their webpage performance nonetheless since it directly impacts the quality of experience for their customers and visitors.

How much will change with Core Web Vitals?

If you have a website that already takes these factors into account, you are well-positioned to capitalize on your previous work.

However, if you haven’t paid much attention towards the performance and speed of your website, you are at a risk of being penalized and dropping further down the SERPs. Here is what you should expect:

Changes to regular search results

The CWV update is going to create substantial changes in regular search results for both desktop and mobile based on the aforementioned criteria. If your website loads slowly or has issues in terms of responsiveness, it is going to be replaced by a competing website that performs better in those aspects.

Criteria for Google Top Stories

You also have to keep in mind that Core Web Vitals will become a contributing factor for your results to show in Top Stories. These involve news results that generally show up at the top of the search engine rankings.

As of yet, AMP was a major requirement to display your website in Top Stories but AMP no longer be compulsory as CWV takes its place.

Greater impact on highly competitive industries

If you are competing in a vertical where there are major brands who invest in their website performance, you are more likely to be affected by these changes.

Keep in mind that there are hundreds of factors that the algorithm takes into account so you still have some time to implement the required changes and improve overall site experience for your users and visitors.

Wider influence of Core Web Vitals

Although, on paper, these might not be the biggest algorithm changes you have seen, there are certain signals that have become increasingly influential in terms of ranking because of their importance in determining user experience.

Keeping all the above factors in mind, Google’s own research demonstrates that the websites that meext the criteria of CWVs are 24% less likely to be abandoned by visitors.

This is exactly why businesses, SEO professionals, and webmasters need to start focusing on improving metrics related to page speed, performance, consistency, and stability.

How to Measure Core Web Vitals

There are a multitude of ways to measure CWVs and Google has continuously expanded the number of tools for the convenience of website owners. Currently, the search engine giant offers 6 different ways to analyze and evaluate LCP, FID, and CLS.

Tools to measure Google Core Web Vitals

  1. Search Console
  2. Google PageSpeed Insights
  3. Lighthouse
  4. Chrome Dev Tools
  5. Chrome UX Report
  6. Web Vitals Extension

1. Google Search Console (GSC)

Search Console now offers a new Core Web Vitals report that allows site owners to analyze their pages across the entire website. In the GSC sidebar, you will find the Core Web Vitals tab.


Google Search Console (GSC)

When you click on this, the Search Console report will display web pages that require your attention grouped by each of the three metrics and based on data accumulated by the Chrome UX report. Ensure that enough data is available for GSC to provide the insights, otherwise, URLs will be omitted from the report.

Using Google Search Console to measure Google Core Web Vitals

Once you believe the issues have been resolved, you can easily validate fixes for the entire group in bulk or by an individual page.

Using Google Search Console to measure Google Core Web Vitals

Source: Wordstream

2. Page Speed Insights

PageSpeed Insights is now compatible with Lighthouse 6.0 which means that it now has the capability of evaluating Core Web Vitals in both the field and lab report sections. CWVs are marked with a blue ribbon for better visibility. Site owners can improve page experience by a wide margin using PageSpeed Insights.

3. Lighthouse

As mentioned above, Google Lighthouse saw an upgrade to the latest 6.0 that includes new metrics, extra audits, and a brand new way to calculate the website's performance score. Two of the metrics included in Lighthouse are Google CLS and LCP metrics. These metrics help in providing diagnostic data to highlight what page needs improvement so you can work on enhancing user experience (UX).

4. Chrome UX Report

Commonly known as CrUX, Chrome UX Report contains public data of real-world user experience accumulated across millions of websites. CrUX report evaluates all Core Web Vitals metrics and Google has recently included a dedicated landing page for Core Web Vitals for improving UX.

5. Chrome DevTools

Chrome DevTools has been updated to enable website owners to identify and troubleshoot visual instability problems on a page, which is a factor for calculating CLS. You need to choose a Layout Shift to see its details which can be accessed from the Summary Tab. Just like Lighthouse, Chrome DevTools also measure TBT which can be seen in the footer.

6. Web Vitals Extension

The Web Vitals extension is available to install from Google Chrome Web Store and enables you to measure all three Core Web Vitals in real-time. This gives you an overview of the metrics allowing you to identify which area of a page needs improvement and which pages don’t.

All of these tools are easily accessible, so you can download them online and start working on improving the page experience of your site.

How to improve your Core Web Vitals metrics

While improving Core Web Vitals and visitor page experience on your site can be a time-consuming process, as discussed above, it’s one that’s well worth it.

Once you have identified and pinpointed the page speed, performance, and visual stability issues that are plaguing your site, you need to make a plan to implement changes. Before you go about making vitals changes haphazardly, it is better to prioritize them beforehand. For instance, if there are issues on the home page, they need to be fixed on a top priority basis while changes on a policy page could be completed later. Having your priorities in place will allow you to improve what matters the most right now for your customers instead of investing your resources on something less valuable.

When it comes to optimizing your website for Google's Core Web Vitals, you need to take all three factors into account and have an individual strategy for addressing these metrics. Instead of trying to go for a comprehensive approach and attempting to fix everything in one go, take your time and experiment with how your changes affect your website. That way, you will be able to find balance and move on gradually instead of making all the changes and modifications in one go.

Improving LCP

You can improve site performance by enhancing LCP through restriction on the amount of content displayed on the site, especially top of the web page. Make sure only critical information is being displayed above the fold. Ask yourself if that information is important for the visitor to solve their problem. If it isn’t, consider moving it down.

Improving FID

Enhancing FID is relatively easy and straight-forward as there are four major areas you need to fix including the following:

  • Reducing third party codes – If there are multiple processes running in the background of a page, it will take longer to load. Delete any non-essential third-party code.
  • Reducing JS loading time – JavaScript is an important part of delivering aesthetic and seamless user experience. However, don’t go overboard and get rid of scripts that are unnecessary.
  • Minimization of main thread loadMain thread work takes most of the burden, so you need to reduce the workload by fixing the site layout and style if you are facing any page speed issues.
  • Implementing lazy loading - this conserves bandwidth by delivering content to users only if it's requested.


Improving CLS

To improve CLS, pay close attention to the size of large page elements and attributes of all media. If you are giving enough space to an element prior to its loading moment, you won’t have to deal with any layout shift issues. It will also help the page to reduce the number of transform animations as they can trigger layout shifts.

Key takeaways

Web vital metrics have become increasingly important to search engine rankings over the years and millions of websites and site owners have already put in a lot of work to improve their page performance, responsiveness, and page speed. That being said, Google’s latest web vital metrics are far more specific, especially when it comes to quantification. Businesses will soon be required by the Google algorithm to improve those areas if they wish to maintain and improve their search rankings.

Improving Core Web Vitals isn’t always an easy job due to the amount of time it takes and the complexity of other SEO ranking factors. That’s why it’s recommended to take this time and start improving your site’s user experience according to Google’s guidelines now, since the tools are readily accessible and Google could deliver their promised 6-month notice at any time.

If you’re making more than $2,000 in monthly ad revenue, contact us today to learn more about how Publift can help increase your ad revenue and best optimize the ad space available on your website or app.

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