Core Web Vitals Report in GA4 and Looker Studio: A Guide on How to Monitor Your Website's Speed Metrics

*Updated on 24.07.2023:

• updated the script version
• added data collection for INP metric
• created tabs in Looker Studio for each metric

Core Web Vitals and other website speed metrics have become critical factors in web design and digital marketing. However, it is not always clear how to analyze and monitor CWV metrics.

This guide provides instructions on how to create an informative report on your website's loading speed using GA4 and Data Studio.

Why Monitor Website Loading Speed in GA4??

To receive and analyze data from real users, not lab data (like in Pagespeed Insights)

Why is this important?

Because lab data doesn't really show how well (or poorly) your website performs.

In short, Lab data is just an emulation of loading one page on 1 device. While real user monitoring shows all the important devices and the real performance of your website's users.

You can read more about the difference between Lab and Field Data here or in my article "Understanding Website Speed".

What does the proposed solution do?

• collects data from users' browsers using GTM
• categorizes it (good, bad, need improvements)
• and sends it to GA4
• creates a report in Looker Studio (based on GA4 data)

CWV report in GA4

The following data is sent to GA4:

So, you can see the percentage of events in each category and compare it with other periods. For example, if Good LCP was 80% and became 65%, this indicates a significant issue with your website's performance.

CWV Report in Looker Studio

Based on the data from GA4, you can create more informative reports in Looker Studio (exData Studio)

Example of such a report is here.

This report provides a detailed breakdown of website performance:

• the total percentage of events in the Good\Poor category
• changes by day\month
• the difference between different devices, browsers, etc.
• filtering by countries, page types, device brands
• etc.

Some real cases of analysis:

1. By analyzing changes day by day, we were able to identify the exact date of changes and determine which development releases caused the changes.

2. Analysis of content groups helped us to quickly determine which type of pages had the most negative impact on overall performance

3. Analysis by device type indicated the reason for the decrease in conversions.?

Who doesn't need this report?

• small business websites
• static websites that are rarely updated

A standard CRUX report that is updated monthly may suffice for their needs.

Who can benefit from it?

• large websites with different types of pages
• websites with active development
• websites with a diverse audience from different countries, devices, etc.

Want the same report?

Follow these steps:

• Import the GTM Recipe* (You can find instructions here)
• Change GA4 ID
• Publish.
• Add to GA4 custom dimension named Category and link it to event parameter
• Copy Looker Studio report?
• Check if the Breakdown dimension is set correctly (it must be Category).
• Change data source to your GA4
• Wait a few days to collect data

*GTM container created based on solution from tagmaNetpeak Agencynageritalia.it for Netpeak Agency