Layout shift causes on React sites

Sites with sibling displacement layout shift causes have a good CLS most often: 72%, against 80% of all React sites. Sites with element box growth shift causes have it least often, at 67%.

Element box growth is the most used: 75.9% of React sites. Sibling displacement is 36.2% of React sites.

On WordPress, 80% of sites use element box growth layout shift causes, and 75% of WordPress sites have a good CLS, against 80% of all sites. On Wix, 61% of sites use element box growth, and 96% of Wix sites have a good CLS.

PlatformLayout shift causes on its sitesGood CLS

React sites with layout shift causes 3,993 sitesElement box growth (box_grow) 76%Displaced sibling element 36%Web font swap text reflow 20%80%

Wix 1,197 sitesElement box growth (box_grow) 61%Displaced sibling element 42%Web font swap text reflow 14%96%

WordPress 1,723 sitesElement box growth (box_grow) 80%Displaced sibling element 33%Web font swap text reflow 25%75%

Element box growth (box_grow) Displaced sibling element Web font swap text reflow Unsized media expansion Late iframe / embed growth

Does the platform explain the layout shift causes difference?

On WordPress, 69% of sites with sibling displacement layout shift causes have a good CLS, against 68% of WordPress sites with element box growth. Within WordPress, sites with sibling displacement and element box growth have a good CLS about equally often. On Wix, 96% of sites with sibling displacement layout shift causes have a good CLS, against 95% of Wix sites with element box growth. Within Wix, sites with sibling displacement and element box growth have a good CLS about equally often.

How different DOM mutations translate into field CLS failures

Not all lab layout shifts hurt real users equally. Sites whose shifts come from web font swaps (20.2%) pass field CLS 71% of the time because line-height adjustments are small. Element box growth (75.9%, 67% good CLS) and displaced siblings (36.2%, 72% good CLS) cause moderate drops, while late iframe and embed growth (0.7%) pulls field CLS down to 56% (median CLS 0.10).