Understanding Real World Data In Google PageSpeed

By James LePage
 on July 8, 2020
Last modified on January 7th, 2022

Understanding Real World Data In Google PageSpeed

By James LePage
 on July 8, 2020
Last modified on January 7th, 2022

In this article we're going to discuss what real world data (field data) in Google PageSpeed is, and how you can use it to improve your websites speed, user experience, and ranking. In this article, we're going to be using the terms real world data, field data, and real user monitoring (RUM) interchangeably.

If the data exists for your URL, Google will display real world data like this:

This field data, or real world data displays at the top of the page speed report, so you know Google is putting an emphasis on it. That means that it's important to focus on and get right.

If your website is new and has no real world data (this could also be the case if it is extremely low traffic), then it simply will not display and you'll need to use lab data instead. It will also display the following warnings:

  • Field Data - The Chrome User Experience Report does not have sufficient real-world speed data for this page.
  • Origin Summary - The Chrome User Experience Report does not have sufficient real-world speed data for this origin.

If this is the case, you can use another tool called fast or slow which uses data from real locations when generating their report.

This report actually has two sections to it. The first section is field data, while the second section is origin summary. Field data displays by default, and origin summary needs to be toggled. We'll discuss the differences in another section of this article, but first let's define each of them.

What’s Field Data In Google PageSpeed?

When real visitors to your website load the page in Chrome, the data is collected And sent to the Chrome User Experience Report (CrUX) dataset. The real world data that you find in any Google data set, such as lighthouse, is collected from this data set. The Chrome user experience report collects data for first contentful paint, first input delay, largest contentful paint, and cumulative layout shift.

These are all important metrics to score high on because Google uses them when ranking your website on its algorithm.

The data that you're seeing here is actually the most accurate and up-to-date that you can get from any Google product, lighthouse included. That's because it continually updates on a trailing 30 day period.

What’s Origin Summary In Google PageSpeed?

Underneath the fields data report, there's a checkbox that allows you to toggle on the origin summary. The only difference here is that origin summary displays real world data for the entire domain, while field data displays real-world data for the single URL that you're testing. This is good to see if your URL is far off the average loading times of the page. If this is the case, you can infer that there is an issue with the page, but not the domain.

Why is it important to understand field data in Google PageSpeed?

Field data, or real-world data is the most accurate information you're going to get. Lab data is calculated from running your Website through a throttled, simulated connection. Real-world data is collected from actual visitors heading to your website.

If you're not doing well in real world data, this is an issue because it's impacting real users. And, because Google is extremely focused on user experience, your rankings go down because of this. Therefore, it's in your best interest to understand field data, and get it right.

There are four major metrics that real world data shows. First contentful paint, first input delay, largest contentful paint, and cumulative layout shift. We have articles on all of them discussing what they are, and how to understand them, but let's summarize them below:

  • FCP: The time it takes for the first content element to display on your screen.
  • FID: The time it takes from the first user interaction to the time that the browser is actually able to process that interaction. This is a core web vital and is dependent on JavaScript and your server speed.
  • LCP: the time it takes for the largest content element to display on the page. This is a core web vital.
  • CLS: the total of all of the layout shifts (that aren't triggered by user interaction) Occurring on your website. This is a core web vital.

In terms of FCP and CLS, content elements are dependent on the page. For example, the largest content element on one page maybe a header. on another page, it may be a featured image.

How To Understand And Use Real World Data in Google PageSpeed

Hopefully the previous section of the article should have given you a good understanding of what field data and what origin summary in Google page speed is, what it measures, and how it is determined. Now let's go over how to actually understand the real world data in Google PageSpeed. In this section, we are only going to be focusing on field data. You can take the lessons from this section and applied to origin summary. Just remember the difference between the two: field data measures the individual page, while origin summary measures the average of the data for the entire domain.

The first thing that you see after fields data is whether you're passing the core web vitals assessment or failing it. It will tell you in plain English that “this page passes the core web vitals assessment” or “this page fails the core web vitals assessment”.

If your page is failing the core web vitals assessment, that means that you need to focus your efforts on resolving any issues that cause you to fail.

Next up, you have your four metrics and their overall scores. The overall score is displayed after the label. For example, for the first contentful paint entry, the overall score is 2.7 seconds. This is the average of all of the data that Google has on hand for that individual URL. It's in your best interest to reduce the average to passable levels.

Underneath that entry, you have the colored graph. this is fairly easy to understand. Referring back to first contentful paint, 18% of the loads for this page have an FCP value that is acceptable to Google. 62% of page loads are classified as “needs improvement” while 20% outright fail and are considered poor by Google. The criteria for the good, needs improvement, or poor values for real world data in Google PageSpeed depends on what you're measuring.

Here's a chart that displays the good, needs improvement, and poor values for each of the four metrics measured in real world data.

How To Improve My PageSpeed Real World Data?

If you find yourself scoring poor, or needs improvement in the majority of your page loads for each metric, you're going to need to improve your page.

This is also dependent on the metrics that you're not doing well in, but typically optimizing your website using a caching solution And migrating to a higher powered server will fix these issues.

If you're on a WordPress website, we recommend taking a look at WP rocket as an all-in-one performance optimization tool, and migrating your website to Cloudways cloud hosting.


This article should have properly introduced you to what real world, or field data in the Google PageSpeed report actually is displaying. It's a great way to gain context on your website and understand how it is loading for real visitors.

It's also a great complement to lab data, which is simulated , though it only displays four metrics.

Understanding how your page loads for real world visitors, and then Lee using the lab data too diagnose any issues that may be causing you to scored poorly will help you boost your page, rankings, and conversions.

As always, if you have any questions about real world data in Google PageSpeed, feel free to reach out in the comment section below.

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3 years ago

Another rather important point on acceleration is optimization and compression of images on the site. You may manually optimize each picture (through Photoshop for example), or automatically (through special services). Here is an interesting article about it:

Article By
James LePage
James LePage is the founder of Isotropic, a WordPress education company and digital agency. He is also the founder of, a venture backed startup bringing AI to WordPress creators.
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