You may have noticed a significant increase in your CLS score without doing anything.
You may see an improvement in your cumulative layout shift (CLS) metrics if you examine your core web vitals report in Google Search Console (see here). Google made a modification in April to decrease the barrier for receiving a “good” green score on that measure, and those metrics are now included in Google Search Console’s report as of June 1st.
What may you see? The majority of sites are unlikely to see significant improvements in their CLS ratings as a result of this study. But some may experience significant increases. “You may see changes in your page CLS statuses (mainly favorable) reflecting this change,” Google noted.
Here’s a figure Glenn Gabe sent on Twitter that shows a significant increase for one site:
Most websites would not experience such a significant impact; here’s another graph I shared:
What changed. The maximum session window with a 1-second gap is set at 5 seconds, according to Google. According to Malte Ubl of Google, this makes the statistic more equitable for long-running pages and single-page apps. Google changed how the statistic is calculated in April. But it took several weeks to collect the data and reflect it in Google Search Console’s reporting tools.
Why we care. With the next page experience improvement in mid-June. This may be one measure you don’t have to spend as much effort trying to improve. After June 1st, review your results to discover where you need to focus your efforts in order to improve your core web vitals. Keep in mind that this is going to be a very mild signal that won’t have much of an influence on your rankings when it goes live.