Core Web Vitals Insights

Healthy core web vitals are key for a user experience, Google rankings, and traffic. See the introduction for more information on the basics, or keep reading below to learn how Marfeel’s CWV module monitors these important metrics, identifies the most urgent issues, and provides solutions.

Group data by dimension and define metrics

Slice and dice the metrics above according to every possible dimension with meaningful combinations of the following 9 dimensions:

  • Country
  • Page technology
  • Host
  • URL
  • OS
  • Browser
  • Browser version
  • Device category
  • Folder

Once you find out which CWV is lagging, it’s time to troubleshoot. One place to start is to filter by country. This will allow you to see if certain regions are slowing you down and help you determine if these are markets that matter for your publication. Check the number of page views you have per country to decide if you can exclude any particular country from your core vitals assessment.

Keep digging. Once you’ve identified important regions that are adversely affecting core web vitals, further investigate the source of the issue. Compare page technologies to gauge if the problem is the same for web and amp versions.

Filtering by KPI

When we are looking at core web vitals, our focus is not only on the total score, but rather on which pages to improve and how urgently. Unfavorable CWV scores are not a huge issue for pages with little to no traffic. For this reason, Marfeel allows publishers to filter core web vitals performing beneath a certain threshold by number of pageviews.

Use Google’s recommendations above as an indicator of where to look. For example, the following publisher has “good” FID score for signals in its 75th percentile:

The FID for each URL appears in order of pageviews, showing all good scores. This is reassuring, perhaps, but lacks actionable insights. In order to prioritize important fixes, the publisher can filter their URLs for FID scores over 100ms in order to find out if they have underperforming URLs with significant numbers of pageviews.

LCP and CLS Offenders

At this point, the publisher has a global understanding (region, page technology, etc) of their site’s core web vitals. They also know which specific URLs are bringing down their scores and have the ability to order those problematic URLs by number of pageviews in order to prioritize which pages require immediate attention.

Great. Now what?

Sure, it’s possible to open the URL and get the developer to look into it. But we know how slow that process can be, which is why we’ve developed a short-cut: Core Web Vitals Offenders for LCP and CLS.

Click on the Offenders button to generate the list of CSS selectors for the elements that are adversely affecting your score on mobile and on desktop.

Once again, prioritizing the most pertinent fixes is key, so the Offenders are listed in order of the number of occurrences on real devices. That’s right, data is not based on synthetic traffic of any kind.

From the list above, select the top priority URLs and open up the Offenders to see which elements are adversely affecting LCP or CLS:

In the example above, it’s clear that the slow render time is being caused by the largest image. Seeing this, and having access to the page itself, the developer knows where to start to improve the LCP. In fact, at Marfeel we have documented a few of the easiest fixes to improve LCP and CLS scores. Find them here.

Note:
The LCP and CLS offenders are tracked as provided by Javascript Performance Observer API.

In case you can't identify a given element, add a CSS class to the suspicious elements. For example, if you see "h2." as an offender, add a unique CSS class to each h2 to identify it.

Follow Up on Fixes Right Away

Adjust the settings to view the data in real time. Check data immediately after a fix is implemented to see if your debugging techniques are working.

There’s no reason to wait around for 28 days while you wait for the CrUX API to catch up and let you know if your fixes were successful. With Marfeel, you can access the same information in real time.

Sign up to start tracking your core web vitals today.

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