Research brief: Website Performance & Revenue — defensible evidence for KW small-business owners (piece 17)
Created 2026-05-22
Status: Research material — not a finished article. Compiled May 22, 2026.
TL;DR
- Faster pages move money, but the size of the effect is sector- and severity-dependent. See
[[deloitte-google-milliseconds-millions-2020]], Vodafone A/B test (2021): 31% LCP improvement → 8% more sales, 15% better lead-rate, 11% better cart-rate,[[rakuten24-cwv-conversion-33pct-2022]],[[redbus-inp-7pct-sales-2023]]. - Core Web Vitals are a real but small Google ranking factor and a much bigger user-behaviour factor — see
[[cwv-tiebreaker-not-major-ranking-factor]]. - For a $5K WordPress refresh vs $20K custom build, performance alone does not justify the custom build. See
[[smb-5k-vs-20k-build-decision-framework]].
Critically, this brief also catalogues what the evidence does NOT support — see [[stats-not-supported-by-evidence]] — so client conversations stop on solid ground.
Depends on
- reference Vodafone A/B test (2021): 31% LCP improvement → 8% more sales, 15% better lead-rate, 11% better cart-rate
- reference Deloitte/Google "Milliseconds Make Millions" (2020): 0.1s improvement → 8.4% retail conversion lift, 10.1% travel
- reference Rakuten 24 (2022 A/B test): CWV optimization → +33.13% conversion rate, +53.37% revenue per visitor, -35.12% exit rate
- reference redBus (2023): INP improved ~72% on search page → +7% sales (6-7.2% CR uplift across operating countries)
Related
- reference Core Web Vitals is a tiebreaker-class Google ranking factor, not a heavy lever — independent studies (Perficient, AWR, Backlinko) corroborate
- rule Speed/conversion stats commonly cited but NOT supported by primary evidence in 2026 — Candid will not quote these
- reference $5K WordPress refresh vs $20K custom build — performance alone does not justify the $15K delta