Source: Search Engine Roundtable by barry@rustybrick.com (Barry Schwartz). Read the original article
TL;DR Summary of Google Core Web Vitals Metrics Update and Reporting Changes
Google recently updated its Core Web Vitals metrics in Search Console, causing a noticeable drop in the number of URLs marked as “good” or “needs improvement,” while the count of “poor” URLs remained unchanged. This change appears across multiple sites and affects both desktop and mobile data. Google representatives confirmed these fluctuations are due to sampling adjustments and ongoing investigations, not bugs or ranking impacts. Separate issues on Chrome’s side may also be influencing Core Web Vitals data without affecting Search Console metrics directly.
Optimixed’s Overview: Understanding Recent Fluctuations in Google’s Core Web Vitals Reporting
Background on the Core Web Vitals Metrics Update
In early July 2025, many website owners and SEO professionals noticed a significant decline in the number of URLs categorized as “good” or “needs improvement” within Google Search Console’s Core Web Vitals reports. However, the count of URLs classified as “poor” remained largely unchanged. This irregular pattern sparked questions about whether a bug or update had been introduced.
Insights from Google Representatives
- John Mueller explained that these fluctuations are normal and result from changes in the sampling process used to gather Core Web Vitals data. Sampling sizes can vary over time, which affects the reported counts but does not necessarily indicate a problem with site performance.
- Barry Pollard, involved in managing the Core Web Vitals project, acknowledged a dip in metrics, particularly on mobile, and shared that the team is investigating the cause and working on a potential fix. He also clarified that this dip should not impact search rankings and is unrelated to Google core updates.
Technical Clarifications and Ongoing Issues
Further clarifications highlighted that:
- The decrease is likely due to fewer URLs being eligible or sampled rather than an actual regression in site performance.
- Chrome’s own Core Web Vitals measurements have shown minor regressions on Android devices, but these do not directly correspond to the Search Console data.
- There may be two separate issues at play: one affecting Chrome’s performance data and another influencing Search Console’s URL sampling and reporting.
What Website Owners Should Know
Key takeaways for webmasters and SEO professionals include:
- Do not be alarmed by the drop in “good” and “needs improvement” URL counts; this is a reporting fluctuation, not a performance crisis.
- Continue to focus on actual site speed and user experience improvements rather than solely on Core Web Vitals report numbers.
- Expect Google to provide further updates as investigations continue, especially regarding mobile metrics.
