At a glance the headline numbers for Third-party categories
Those third parties grouped by what they do.
12.6% of sites carry analytics. 4.5% embed video players.
The third-party categories mix who uses what, and how stable each group is
Third-party categories. On the fleet: 20.6% cdn, 18.1% framework, 12.6% analytics. 100.0% of sites use at least one cdn.
Passing CLS per bucket every category and count level at once - color is the pass rate
Each row is a category, each column its own count bucket (few on the left, many on the right); the cell is the share of those sites passing CLS.
Rum swings the hardest: 83% of sites pass CLS with few, 64% with many. computed
Few vs many - does quantity cost CLS? the pass rate with few vs many of each category
Per category: the pass rate among pages with FEW of it (hollow ring) against pages with MANY (solid dot), worst trend first. Thin buckets are excluded from the endpoints.
More Rum costs the most: the CLS pass rate falls from 83% with few to 64% with many. computed
Why this matters for the Core Web Vitals, and where to start fixing it
Third parties grouped by what they do, and the category predicts the damage. Ads and chat inject visible UI, so they shift layout (CLS). Analytics and tag managers run code, so they block interactions (INP). Font and CDN services sit on the render path, so they delay paint (LCP).
Budget per category, not per tag. Most stacks need at most one of each: one analytics tool, one tag manager, one chat widget. The duplicates are where the easy wins live.
Chrome field data from 189,915 sites, representing millions of real page loads. How we measured.