You’ve installed Trellis, so you're hoping to pass all elements of Google's Core Web Vitals (CVW) and we want you to be passing also. However, there can be a number of factors that can cause you to not pass CWV outside of the Trellis Theme.
Understanding Core Web Vitals
Core Web Vitals are a set of page experience criteria that are a part of Google’s ranking algorithm starting in June 2021.
The main components are:
Largest Contentful Paint (LCP) When does the main content element of the page become visible to users.
First Input Delay (FID) How long does it take for your page to become usable to a page visitor?
Cumulative Layout Shift (CLS) Does your content shift as the page loads or as the user scrolls?
Total Blocking Time (TBT) How long is your content blocked before it becomes usable?
We suggest running a few of your top posts through Google’s own Page Speed Insights tool. It's important to know where to look and what you're looking for. There are two measuring tools on Page Speed Insights for Core Web Vitals, the Field Data and the Lab Data.
The Field Data is aggregate data collected over a 28 day period and the Lab Data provides a more sanitized version of your site to catch common issues on page load.
Since the Field Data is an average of 28 days of data, you will not be able to count on it for up-to-date measurements if you made changes within the past 28 days.
Lab Data only looks at the first screen view, while Field Data looks at how readers are interacting with a page for the entire session. That combined with the 28 days can make locating problems that are below the fold relatively tricky.
Using the CWV extension is the best bet to confirm or deny issues below the fold.
When you test your site in Google Page Speed Insights, you will see both of these measurements:
Note: Where Google measures the CLS & LCP Metrics using both the Lab Data and Field data, FID is measured only in the Field but the corresponding Lab Metric is TBT (Total Blocking Time).
What about the errors in my Google Search Console?
Google Search Console (GSC) will use the Field Data measurement tool to alert you of issues with your CWV. If you are sure you have resolved the issue with your CWV, then you can initiate the Validate Fix button in GSC. It can take up to 28 days after validating the fix to see if the issue has been completely resolved.
I’ve done everything suggested and my Lab Data is not passing CWV.
If your Core Web Vitals aren't passing in the Lab Data metric, you can scroll down in the PSI report above the "Opportunities" heading and filter the data to see what items are affecting various metrics:
Optimizing Ads for CLS, For Mediavine Publishers
If you are a Trellis user & a Mediavine Publisher, navigate to your Mediavine Trellis > MVP tab and ensure that Optimize Ads for CLS is enabled. That's it! Your Ads are now optimized for CLS in Trellis.