Measuring Core Web Vitals: Part 3

In Part 1 of our series on the Core Web Vitals, we discussed what metrics Google is using for its Core Web Vitals update. Part 2 went a little more in-depth about how those metrics can be understood. In order to understand how those metrics are measured and understood, we have documented below what we have seen in looking at the tools available.

Where is Google Getting Their Core Web Vitals Data From?

There are three data points that Google shares regarding the Core Web Vitals, all of which can be found in Google’s PageSpeed Insights Report. While Google is using Field Data to establish your Core Web Vital scores, it also provides additional metrics related to page performance. All of which are run for both desktop and mobile performance. 

Field Data

This is data that is collected by Google Chrome users for the page-specific URL. It is not live data – it is based on the Chrome User Experience Report, which gathers anonymized data points from real-time visitors from the previous 28 days for the tested URL.

These data points show both the 75% average score of these metrics as well as a breakdown of how the distribution of scores fall within the “Good/Needs Improvement/Poor” categories. This is generated only for URLs tested (which we will touch on in the next section).  Within the Field Data Report, the First Input Delay (FID), Largest Contentful Paint (LCP) and Cumulative Layout Shift (CLS) are used to determine your core web vitals performance

Origin Data

This is similar to Field Data but represents the aggregated performance of ALL pages on your website.  It provides a comparison view of your entire site versus the individual page you are testing in PageSpeed Insights.

Both the performance breakdown and the 75% average scores are illustrated in this section of the report.

Lab Data

Lab data is real-time analysis data but the connection speed is simulating a mobile network throttling at a lower speed (3G connection). This allows Google to run live performance tests for individual URLs to compare against the Field Data and the Origin data. It reflects the speed at the time the test was run and is powered by Lighthouse technology. 

There are several external factors that could also impact this score including VPN connection, location of test, connection strength and more.

Essentially, the Origin Data and Lab Data provide additional information to help SEOs decipher the Field Data Report by providing additional information to compare and contrast.

What to Focus on When Reviewing PageSpeed Insights Data

PageSpeed Insights is a great tool for understanding the various metrics that go into Core Web Vitals. It can also be confusing since it provides a lot of data points, and only a few of them are relevant to Google’s Core Web Vitals.

What You See in PageSpeed Insights

What You Should Focus on in PageSpeed Insights

As discussed in Part 1 of our series, the only data to pay attention to here is the Largest Contentful Paint (LCP), the First Input Delay (FID), and the Cumulative Layout Shift. The rest is information that is useful, as it aides in overall page performance but does not reflect the Core Web Vitals themselves. 

Adding in Google Search Console Data

At TopSpot, our SEO Team is utilizing Google Search Console to help determine how and where to make relevant adjustments to our Clients’ websites as a whole, along with what to prioritize in order to make the largest impact. Similar to the Field Data in the PageSpeed Insights report, Google Search Console’s data is also populated from aggregated Field Data from the Chrome User Experience Report. The difference is that GSC includes a page-by-page performance breakdown that isn’t available in other tools. It also gives more specific information about what is and is not working for a particular website page. 

For example, in the report below, we can see that this website has 418 pages, and for 141 of those pages, the LCP scores are an area of improvement.

What’s important to note, is that this report measures all three metrics of Largest Contentful Paint, First Input Delay and Cumulative Layout Shift. If a domain doesn’t meet the minimum traffic threshold, it is omitted from the report (learn more about minimum traffic thresholds in Part 2 of our series).

Search Console utilizes URLs groups that batch URLs that provide a similar user experience together, as it can be assumed that the similar pages have the same underlying performance problems. Also, once the URL has the appropriate amount of data for any metric, the page status will reflect the status of the most poorly performing metric. All three metrics need to be in a “Good status” for over 75% of page requests in order to benefit from the Core Web Vitals update. 

Other Tools Out There 

Every day, new tools are popping up to be used to help developers and website owners understand how the Core Web Vitals are being used and how to approach them. As those tools become available, TopSpot is evaluating what differentiates them and choosing what works best for our clients. 

What This Means For You

Knowing how to measure the Core Web Vitals is crucial to making strategic adjustments to your website to get a “Good” rating. Since the page’s overall success is based on all three metrics, knowing how to read the various reports will help you determine the best overall action plan for your business’s organic presence.

When it comes to the Core Web Vitals, there is a lot of information to parse through. If you need a refresher of what some of these metrics mean, revisit Part 1 and Part 2 of our series on the subject and then head over to Part 4 where we answer some commonly asked questions about the Core Web Vitals.