WordPress cacheable resource share and the Core Web Vitals

Sites with 50% to 79% cacheable resources cacheable resource share have a good LCP most often: 75%, against 70% of all WordPress sites. Sites with under 20% cacheable resources cacheable share have it least often, at 66%.

80%+ cacheable resources is the most used: 38.7% of WordPress sites. 50% to 79% cacheable resources is 17.3% of WordPress sites.

Across the four LCP sub-parts in Chrome's field data, the largest gap between 50% to 79% cacheable resources and under 20% cacheable resources sits in time to first byte (TTFB): 994 ms median for 50% to 79% cacheable resources against 1247 ms for under 20% cacheable resources. Overall median field LCP is 1.8s for 50% to 79% cacheable resources (TTFB 994 ms, load delay 328 ms, load duration 151 ms, render delay 245 ms) versus 2.1s for under 20% cacheable resources.

On jQuery, 39% of sites use 80%+ cacheable resources cacheable resource share, and 69% of jQuery sites have a good LCP, against 70% of all sites. On Vue, 41% of sites use under 20% cacheable resources, and 68% of Vue sites have a good LCP.

FrameworkCacheable resource share on its sitesGood LCP

All WordPress sites 63,295 sites80%+ cacheable resources 39%Under 20% cacheable resources 36%50% to 79% cacheable resources 17%70%

Alpine 380 sites80%+ cacheable resources 37%50% to 79% cacheable resources 32%Under 20% cacheable resources 18%20% to 49% cacheable resources 13%80%

jQuery 60,314 sites80%+ cacheable resources 39%Under 20% cacheable resources 36%50% to 79% cacheable resources 17%69%

Vue 4,844 sitesUnder 20% cacheable resources 41%80%+ cacheable resources 41%50% to 79% cacheable resources 12%68%

React 2,233 sites80%+ cacheable resources 46%Under 20% cacheable resources 30%50% to 79% cacheable resources 16%61%

80%+ cacheable resources Under 20% cacheable resources 50% to 79% cacheable resources 20% to 49% cacheable resources

Does the framework explain the cacheable resource share difference?

On jQuery, 74% of sites with 50% to 79% cacheable resources cacheable resource share have a good LCP, against 72% of jQuery sites with 80%+ cacheable resources. Within jQuery, sites with 50% to 79% cacheable resources have a good LCP more often. On Vue, 77% of sites with 50% to 79% cacheable resources cacheable resource share have a good LCP, against 72% of Vue sites with 80%+ cacheable resources. Within Vue, sites with 50% to 79% cacheable resources and 80%+ cacheable resources have a good LCP about equally often.

How subresource Cache-Control coverage speeds up repeat visits and CDN edge hits

Cacheable resource share tracks the percentage of page requests carrying valid Cache-Control or Expires headers. Across 24,509 sites (38.7%) with 80%+ cacheable resources and 10,954 sites (17.3%) at 50% to 79%, 72% and 75% pass field LCP (1.9s and 1.8s median). When cacheability falls to 20% to 49% (8.1%), good LCP drops to 70% (2.0s median), and below 20% cacheable (35.9%, 22,712 sites) good LCP drops to 66% (2.0s median).