For the last four months, Google has been miscounting the mobile page experience data in the Google Search Console reports. This impacted both the performance report and the page experience report in Google Search Console. The issue persisted from June 29th through November 1st – yes, for over four months.
What Google said. Google posted this notice in the data anomalies page saying “June 29 – November 1: Search Console was overcounting mobile Page Experience data during this period. On November 1 you should see a return to correct data.” This was posted both under the page experience report and the performance reports sections, which means both those reports were impacted.
Annotation added. Google added an annotation to the reports showing that on November 1st, Google resolved the issue. You can see the little 1 circle at the right side of this chart documenting the issue.
More details requested. I did ask Google for more details on how this may impact the reporting. Will we see the percentage of good URLs drop for some sites, what will happen to the average set of charts and data in Search Console. As of right now, I scanned through dozens of Search Console properties and did not see any change to those metrics on November 1st. Maybe we will see changes tomorrow, when November 2nd data comes up.
Why we care. A lot of SEOs over the past year or so have been, how do I say it, obsessed with the page experience and core web vitals metrics. A lot of SEO companies have been selling this as part of their services and providing reports to clients about the improvements the sites have made with these scores.
The next time you provide these reports to your clients, you may need to note that Google had an overcounting issue for the past four months and that is why there may be changes to the numbers after November 1st.