Shopify CLS shift concentration and the Core Web Vitals

Sites with a single dominant shift CLS shift concentration have a good CLS most often: 86%, against 86% of all Shopify sites. Sites with multiple compounding shifts shift concentration have it least often, at 79%.

A single dominant shift is the most used: 57.5% of Shopify sites.

Vue sets the CLS shift concentration to a single dominant shift on 55% of its sites, and 80% of Vue sites have a good CLS, against 86% of all sites.

FrameworkCLS shift concentration on its sitesGood CLS

Shopify sites with CLS shift concentration 5,389 sitesSingle dominant shift (95%+) 58%Mostly one shift (65-94%) 24%Multiple compounding shifts (<65%) 19%86%

jQuery 2,327 sitesSingle dominant shift (95%+) 53%Mostly one shift (65-94%) 25%Multiple compounding shifts (<65%) 22%80%

Vue 669 sitesSingle dominant shift (95%+) 55%Mostly one shift (65-94%) 24%Multiple compounding shifts (<65%) 21%80%

Single dominant shift (95%+) Mostly one shift (65-94%) Multiple compounding shifts (<65%)

Does the framework explain the CLS shift concentration difference?

On jQuery, 81% of sites with a single dominant shift CLS shift concentration have a good CLS, against 72% of jQuery sites with mostly one shift. Within jQuery, sites with a single dominant shift have a good CLS more often. On Vue, 82% of sites with a single dominant shift CLS shift concentration have a good CLS, against 67% of Vue sites with mostly one shift. Within Vue, sites with a single dominant shift have a good CLS more often.

One isolated layout jump versus cascading multi-element shifts

CLS concentration measures the ratio of the single largest layout shift to total lab CLS on pages with non-zero shift. Across 3,099 sites (57.5%) where one isolated element accounts for at least 95% of total CLS, 86% pass field CLS. When secondary shifts join in (23.7% at 65% to 94% concentration), good field CLS drops to 79%, and when shifts are spread across multiple compounding events (18.8%, 1,011 sites), good field CLS falls to 79%.