Deloitte/Google "Milliseconds Make Millions" (2020): 0.1s improvement → 8.4% retail conversion lift, 10.1% travel

Claim: Deloitte Ireland and Google measured 4 industry-wide site-speed metrics and found that a 0.1-second improvement correlated with:

• +8.4% retail conversions
• +9.2% average order value (retail)
• +10.1% travel conversions

Source: "Milliseconds Make Millions" — Deloitte Ireland / Think with Google PDF, 2020 (foundational, still widely cited).

Confidence: Verified (Deloitte primary).

Why it earns its place: The most-cited industry-wide study of site speed → revenue. Magnitudes are conservative (compared to individual-site studies like Vodafone A/B test (2021): 31% LCP improvement → 8% more sales, 15% better lead-rate, 11% better cart-rate which show larger lifts), which makes it more credible as a baseline estimate for SMB conversations.

Caveat for SMB application: None of the foundational performance-revenue studies (Vodafone, Pinterest, Walmart, BBC, Deloitte) measured small-business marketing sites. Extrapolating to a Kitchener-Waterloo dental practice is plausible but unproven. Treat the magnitudes as directional indicators of that the relationship exists, not precise predictions for any specific client.