{"id":346,"slug":"bbc-10pct-user-loss-per-second","title":"BBC: lost 10% of users for every additional second the site took to load","kind":"reference","scope":"business","status":"current","audiences":["claude-code","candid-team"],"topics":["core-web-vitals","measurement"],"reference_body":"**Quote (web.dev/learn/performance, 2024):**\n\n> \"BBC lost an additional 10% of users for every additional second the site took to load.\"\n\n**Source:** <https://web.dev/learn/performance/why-speed-matters>\n\n**Confidence:** Verified.\n\n**The cleanest \"speed loss curve\" stat in the public literature.** Loses 10% per additional second is roughly linear over the relevant range (1-5 seconds), which makes it a useful \"rough calculator\" for client conversations: \"if your LCP is 4 seconds and the median is 2.5, you're losing roughly 15% of users to that 1.5-second penalty.\"","rationale_body":null,"metadata":null,"links":{"outgoing":[{"slug":"vodafone-31pct-lcp-8pct-sales-2021","title":"Vodafone A/B test (2021): 31% LCP improvement → 8% more sales, 15% better lead-rate, 11% better cart-rate","kind":"reference","scope":"business","link_type":"relates-to"}],"incoming":[{"slug":"research-brief-page-speed-moat","title":"Research brief: Page Speed as a Moat — why CWV separates the agencies from the freelancers (piece 9 of 15)","kind":"reference","scope":"business","link_type":"relates-to"}]},"created_at":"2026-05-22T20:03:33.357Z","updated_at":"2026-05-22T20:03:33.357Z"}