I have a site that has "99.9% URLs with a good page experience" (on mobile) and no issues with core web vitals, mobile usability, security, or HTTPS (all URLs pass on all fronts). This has been the state of the site for over two months now.

My understanding is that this should imply that (almost) all mobile search impressions for the site should be marked as having a "good page experience", so "good page experience" mobile search impressions should be (close to) 100% of mobile search impressions, and "good page experience" mobile search clicks should be (close to) 100% of mobile search clicks.

However, "good page experience" mobile search impressions are a little under 50% of mobile search impressions, with the percentage staying around 50% each day. "Good page experience" mobile search clicks are a little under 90% of mobile search clicks (this pattern holds for data restricted to a recent week, well after everything turned green in search console). I'm accessing "good page experience" by using the Search Appearance drilldown available in Google Search Console.

I tried digging into this by downloading CSVs for impressions broken down by page, and then diffing the CSV for overall mobile search impressions with the CSV for "good page experience" mobile search impressions. I found that in many cases, a single page has some "good page experience" mobile search impressions, but not all the mobile search impressions for that page have good page experience. Since the pages in question have had "good page experience" for the whole duration, I would expect to see all their mobile search impressions as having good page experience.


3 Answers 3


Core Web Vitals are not always available for all the URLs.

Ref: https://support.google.com/webmasters/answer/9205520?hl=en

The report is based on three metrics: LCP, FID, and CLS. If a URL does not have a minimum amount of reporting data for any of these metrics, it is omitted from the report.

"Page experience on mobile" report is based on the URLs for which the core web vital metrics have been measured (field data) by Google. Also, it seems only those URLs with field data show up on the "Good Page Experience" drill down in the "Performance" report.

Note: In my case, I compared the total impressions of Good URLs on the Page Experience report and the total impressions from Good Page Experience drill down. The numbers are very close.

  • All the information you posted seems correct, but I don't immediately see how it explains all my observations, specifically about urls for which some but not all mobile search impressions are marked as having good page experience.
    – Vipul Naik
    Commented Jun 21, 2021 at 4:18
  • The only explanation I can think of is this - Google isn't collecting and/or attributing page experience to the impressions that are left out. Also, that doesn't seem to mean that the left-out impressions had a poor experience.
    – Kannan
    Commented Jun 21, 2021 at 4:57

Not Enough Field Data

It's because some % of pages aren't getting enough traffic to gauge it. Page Experience is calculated based on Field Data, not Lab Data.

This is why in many cases, a single page has some "good page experience" mobile search impressions, but not all the mobile search impressions for that page have good page experience.

Field data requires a certain sample from various different browsers/devices.

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Where a result exists on a SERP does not factor into this data.

Here's an insightful clip of Martin Splitt talking about the differences between Field Data and Lab Data. It's from an SEO office hours back in June.


This does not mean that some of your pages do not have a good page experience.

It simply means that Google is only certain about X% of your pages!

If you optimized your site for Core Web Vitals, you're probably fine dude. I'd recommend testing pages not included in your Page Experience report via WebPageTest on a 4g/mobile connection or in Dev Tools with your connection throttled.

If you go the dev tools route (fastest) below are some values for custom throttling presets. You should already have regular 3g, I had to add good 3g and regular 4g myself.

Regular 3G,750,250,100
Good 3G, 1000,750,40
Regular 4G, 4000,3000,20


It is very possible that some of your content ranks well on desktop, but not mobile, because it's better suited for a desktop experience. It might just take a bit longer to get that data : )

  • Thanks for sharing your thoughts! My question, however, was for situations where the same page has some impressions with good page experience and some without -- and I don't think your answer addresses that?
    – Vipul Naik
    Commented Sep 30, 2021 at 14:41
  • @VipulNaik I believe it does...the same page could have a different page experience depending on if it's desktop or mobile. If some impressions are being counted as a "good experience" and others are being counted as a "poor experience", then you've got an issue somewhere with how that page is being loaded. But your question does not mention "poor experience" So I recommended testing as many devices and connections as possible. If your Core Web Vitals are actually optimized, the problem would be that there's not enough field data/traffic to gauge it Commented Sep 30, 2021 at 17:55
  • My question was limited to some mobile search impressions of a url being marked as good page experience and some as not having good page experience. Desktop/mobile differences wouldn't explain this.
    – Vipul Naik
    Commented Sep 30, 2021 at 18:30
  • @VipulNaik I partially misunderstood your question, I'll revise my answer. However, connection varies across mobile, and we're dealing with Field Data. Google is measuring performance on a per user basis. Poor performance on slower connections could explain it, which is why I recommended you test if you pass Core Web Vitals on various connections. I have another idea as well but I have to validate it first. Commented Sep 30, 2021 at 21:16

My tentative conclusion based on further analysis of data from early September 2021 is that some impressions are excluded from consideration for good page experience based on the place in the search results that the item shows up.

For mobile searches, it looks like results that show up in "Notable moments" are excluded from consideration.

For desktop searches, it looks like only results in the "Top stories" carousel are eligible for consideration.

I couldn't find official documentation from Google for this, so my inferences could be incorrect -- and even if correct at the time of analysis, they may no longer remain valid after further updates from Google, that they have no obligation to announce.

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