Google’s Core Web Vitals update is out: what now?

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After announcing that Core Web Vitals would have been brought into search back in November 10, 2020, Google finally released its dreaded Page Experience Update in two rounds, one finished on June 12, another one rolled out more quickly, effectively completing the much-anticipated core web vitals update on July 7, 2021.

There has been much chatter and a fair deal of panic among SEO professionals and website owners about the potential impact of this update – one that Google bothered announcing in advance – on the search performance of websites. Almost one month in, we can draw some conclusions, debunk some myths, and reduce panic and confusion relative to the June-July 2021 Core Web Vitals update.

What are core web vitals?

Core Web Vitals are three performance KPIs against which Google measures the overall user experience quality. Core Web Vitals include loading speed, user interaction, and visual stability. The three KPIs are named Largest Contentful Paint (LCP), First Input Delay (FID), and Cumulative Layout Shift (CLS). 

Core Web Vitals are nothing new, as Google has been stressing the necessity of providing the best possible user experience for a long time coming, switching to mobile-first indexing from March 2021, and providing their own tool to diagnose Page Experience and speed issues in PageSpeed Insights. Therefore, it should come as no surprise that Google is giving more and more importance to UX and speed performance of websites. Core Web Vitals are part of a more extensive set of indicators Google uses to provide Page Experience an overall score.

To help you diagnose and act on your Core Web Vitals score, Google added a Core Web Vitals tab in the experience drop-down in Google Search Console. There, you can view your Core Web Vitals performance, the number of URLs that have a “poor” and “needs improvement” score.

Great, now you found what Google thinks of your website. It’s time to understand a bit more about why your website is failing and what you can do to prevent it.
Let’s look at how Google evaluates your website and understand each metric better:

Largest Contentful Paint

Simply put, Largest Contentful Paint measures how long it takes for the largest content element (usually the most important)in your URLs to become visible. The final score will be the average time it takes to render the page’s main content; hence, the biggest factor influencing largest contentful paint is typically loading speed. A sloppy server, render-blocking resources, slow load time, and client-side rendering are often culprits if you are failing the Core Web Vitals audit for a bad LCP. LCP is related to First Contentful Paint, which measures the amount of time it takes for a user to see the first DOM content on screen.

Google scores Largest Contentful Paint in the following categories:

  • good – between 0 and 2.4 seconds
  • needs improvement – between 2.5 and 4 seconds
  • poor – 4 seconds and above

First Input Delay

First Input Delay (FID) measures the time from when a user first interacts with your website – be it a click, tap, a Javascript event – and the browser can respond to that interaction. In a few words, it is the time that passes between a user’s first interaction with your website and the browser’s response to that first interaction, measured in milliseconds. FID does not consider scrolling and zooming as a first interaction; therefore, it does not include these actions in the score. 

Even though the declining attention span is probably a myth, making a good impression is crucial, especially on websites, where users have little to no patience and virtually endless alternatives.

There is very little doubt about what’s causing your website to have a poor First Input Delay, and it is typically a heavy Javascript execution. Optimizing the parsing and execution of Javascript on your pages will directly improve your first input delay.

Google scores First Input Delay in the following categories:

  • Good – between 0 and 100 ms
  • Needs improvement – between 100 and 300 ms
  • Poor – above 300 ms

Cumulative Layout Shift

Another UX-related metric, Cumulative Layout Shift (CLS), is a critical indicator that quantifies the frequency with which users experience sudden layout shifts. The lower CLS is, the better the user experience will be. Sudden movements in the template can affect UX, desturbing the reader and altering how the page looks. Every time a visible element changes position in consecutive frames, the crawler records a layout shift. The CLS score you can find in PageSpeed Insights and Google Search Console is a measure of the most significant layout shift scores during the entire lifespan of a webpage. The way the CLS metric is calculated has recently changed, using layout shift bursts rather than considering the whole session and summing the scores, giving more justice to pages designed to remain open for longer (and would therefore have an inflated CLS).

Google classifies CLS as:

  • Good – below 0.1
  • Needs improvement – between 0.1 and 0.25
  • Poor – above 0.25

Do Core Web Vitals affect SEO?

In short, yes. And they always have. Core Web Vitals affect your website’s user experience; hence, they already influenced your website’s ranking before Google made it an official ranking factor in June and July 2021. Findings by Searchmetrics’ Core Web Vitals study by Marcus Tober from April 2021 (when Google had not yet deployed the Page Experience Update) show a strong positive correlation between Core Web Vitals performance and Google Rankings. The correlation, calculated on a sample of over 2 Million URLs, ranges from 0.04 to 0.2 for the various metrics and is expected to increase now that Google introduced Page Experience in search. 

Even though this correlation is proven, the study still claims that only 4% of all websites pass the Core Web Vitals audit, meaning that you can still rank well even if you are not offering a perfect UX.

Should this mean you can ignore CWV? No, it does not.

Sometimes Google can ignore Core Web Vitals fails for websites that still perform great in terms of CTR or have a super authoritative domain. YouTube, for example, still ranks well despite having poor LCP and FID and an improvable CLS. Why? Because it is YouTube, it has billions of monthly active users, and you can expect they have great CTR. If other websites do it, it does not mean you should not be striving to create the best possible User Experience.

On the other hand, there is no need to panic, as there are over 200 ranking factors, and Core Web Vitals play a part, but the focus on quality, relevant content should always be the drive of your business.

How are Core Web Vitals measured?

Google measures Core Web Vitals (CWV) by gathering anonymised data from Chrome users to calculate their Core Web Vitals Score and makes these available for everyone in the Chrome User Experience Report (CrUX). Google uses CrUX data to score every website and updates CrUX every 28 days, similarly to PageSpeed Insights.

There are two ways you can assess your website’s performance regarding CWV:

  1. CrUX (Real-world data) – Google makes their CrUX API free and available, and this source of data, gathered from real visitors coming to your website, hence representative of your population and gathered first-hand. This type of data, also called Field Data, is the source Google uses to score your pages concerning Page Experience. The drawback with using CrUX is that data is available only for the most popular pages on the web, meaning that probably CrUX scores would be available for a handful of your website’s pages, at best. Luckily, CrUX features an origin summary, summing up the data for your website on an aggregate level.
  2. Pagespeed Insights (Lab data) – provided by Google and powered by Lighthouse, PageSpeed insights measure page performance at the URL level. You can submit your website’s most important URLs to diagnose what is wrong and what is working, and create a technical task log to improve your performance and, eventually, your PageSpeed score. PageSpeed data now include a summary of the origin performance from CrUX and, if available, CrUX data for the specific URL.

How to audit and improve your Core Web Vitals

Here we are. Now, you know exactly (or kind of) what Core Web Vitals are, how important they are, and how your website performs in that department. You know your website is not passing Google’s CWV tests, and you have seen your rankings tank, or you simply want to improve your website’s UX regardless of Core Web Vitals. 

How do you audit your website and enhance your CWV scores at scale?

Here is what you will need:

Protip: Ahrefs audits now include CrUX and PSI data for your website. If you are subscribed to Ahrefs, you can add the CrUX and PageSpeed insights columns to your page explorer report.

  1. Get PageSpeed Insights API and connect it to Screaming Frog
  2. Crawl your website
  3. Export the crawl
  4. Process the data on Google Sheets
  5. Create a Data Studio Report
  6. Step 6: Create a Technical Log and improve Core Web Vitals

Step 1: Get PageSpeed Insights API and connect it to Screaming Frog

If you want to measure Core Web Vitals for your website at scale, you need to get ahold of the free PageSpeed insights API. Find out how here.

Next, open Screaming Frog. Then, go to Configuration-> API Access -> PageSpeed Insights. Enter your key and press connect.

Important: Screaming Frog’s base configuration does not include tests that will significantly make your life easier (e.g., you will not find CrUX categories, but only the raw metrics). 

Hence, after connecting your PageSpeed Insights API to Screaming Frog, head to the “metrics” tab, expand CrUX Metrics, and select “CrUX First Input Delay category, CrUX Largest Contentful Paint category, and CrUX Content Layout Shift category.” If your website has little traffic and is relatively small, also check the CrUX Origin categories to make sure you’re not out of data entirely. Next, do the same for the Lighthouse Metrics. Finally, go to the Opportunities tab, where the default configuration only selects savings in terms of milliseconds. Check the boxes for all the KPIs that matter to you to quantify the Kb you will save on every single URL.

The Diagnostics tab is excluded by default, but feel free to check it if you want to have a complete audit.


Step 2: Crawl your website

Let Screaming Frog crawl your website (don’t forget to exclude the PageSpeed Insights bot traffic before you press run) and check all your URLs, one by one, for Core Web Vitals score. If your website is extremely large, you can list crawl your most visited pages so that you spend time and energy only on your critical URLs.


Step 3: Export the crawl

Well done! Your crawl is finished, the PageSpeed APIs have done their job, and now you have all the data and advice you need to tackle your low-hanging fruits. Now it’s time to export your crawl and get your PageSpeed data into a Google sheet. Still from Screaming Frog, navigate to the PageSpeed tab, press export, and get all your data on Google Sheets, where part of the analysis and reporting can occur.


Step 4: Process the data on Google Sheets

Now that you have all the data, after analysing it from Screaming Frog (which tells you at a glance how many URLs are flagging PageSpeed Insights recommendations), you can pinpoint your low hanging fruits.

If you crawled the essential pages only, you can delete the unnecessary column, group data and keep what you will need for your analysis.

Remember to do all the housekeeping you need now, as the file will serve as the source for your Data Studio report. 

Quality of life tip: to visualise the savings as Kb, Mb etc., go to Google Sheets->Format->Number->More formats->Custom number format and add the following string:

[<1000000]0.00,” KB”;[<1000000000]0.00,,” MB”;0.00,,,” GB


Step 5: Create a Data Studio Report

Visualisation is essential when it comes to data, and having an interactive report to help you navigate the different areas of CWV your website needs to improve on is vital now as Page Experience is officially a ranking factor. 

Lazarina Stoy saved everyone tons of work by creating a Data Studio Dashboard that shows CWV performance for every website URL. 

To configure it correctly, make a copy, use your previous Google Sheet as a source, and add CrUX as another source, using your website’s address.

CrUX data will show in the charts, while your previously crawled data will allow you to populate the tables.

You can sort the data by most considerable savings, filter by website sections and really get a feel for what you need to work on to make your website better. This dashboard is handy for in-house staff or agency specialists who want to help their clients visualise Core Web Vitals performance.


Step 6: Create a Technical Log and improve Core Web Vitals

Great. You analysed your website, studied Core Web Vitals and created a pretty report. Now the serious part starts; implementing what we’ve learned so that, in the not-so-far future, the dashboard will be useless since you will be passing every CWV test with flying colours.

When it comes to improving the technical side of a website, keeping organised is essential, and CWV optimisation is no different. You need to draft a document that is both readable for your client/marketing team and that the developers will understand. Use colours to track completions and explicitly state who’s responsible for what.

Prioritise tasks accordingly, and try to quantify effort as well as you can.

We know that devs and SEOs don’t always speak the same language, but it is crucial here that all the stakeholders are aligned, as everyone’s goal is the same: improving your website’s performance, and therefore rankings. At GA Agency, we use this simple but neat CWV Progress Tracking Sheet. It includes everything you need, relevant links to PageSpeed insight tips, prioritisation, and the effort required.

Feel free to make a copy and use it for your own purposes.

My website is failing Core Web Vitals tests; what do I do?

Do not panic. As we mentioned before, studies show that so far, only 4% out of 2 Million URLs analysed currently meet all the Core Web Vitals standards. They still rank, because good content and authority tend to win.

Still, having a plan to make your UX as smooth as possible should always be one of your top priorities, as it directly affects both the quality of your traffic and your website’s rankings.

There are two solutions to your problem:

  1. Scroll back to the top of the article and start working on improving your website: you can do it! Start from this post and our five tips to prepare for Google’s Page Experience update.
  2. Acquire SEO consulting services. If you’re moving in uncertain waters in terms of SEO, it’s easy to make mistakes you won’t be able to trace. Rely on an expert partner, and get your SEO back on track. Get a full service that will tackle both your technical and content issues, making sure you make the most of your online opportunities with a 360° SEO strategy.

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