We only cite numbers we can trace.
The SEO industry is full of statistics nobody can source. This page lists the ones we actually use, where they come from, and what they do and do not prove.
This page collects the primary sources DenverSEO.io relies on: government data, standards bodies, peer-reviewed or methodology-backed studies, and official documentation from Google and AI companies. Each entry states the finding, the source and a link.
A 0.1-second improvement in mobile site speed increased retail conversion rates by 8.4% and travel conversion rates by 10.1%, across 37 brands and more than 30 million sessions.
Source: Milliseconds Make Millions, Deloitte for Google (2020), via web.dev
34% of U.S. adults say they have used ChatGPT, about double the share in 2023. Among adults under 30, the figure is 58%. Survey of 5,123 adults, Feb 24 to Mar 2, 2025.
Source: Pew Research Center (June 2025)
Google's "good" thresholds: Largest Contentful Paint 2.5 seconds or less, Interaction to Next Paint 200 milliseconds or less, Cumulative Layout Shift 0.1 or less, measured at the 75th percentile.
Source: web.dev (Google)
Google states there are no additional requirements to appear in AI Overviews or AI Mode beyond standard SEO best practices: pages must be indexed and eligible to show with a snippet.
Source: Google Search Central
Google processes JavaScript pages in three phases, crawling, rendering and indexing, and rendering may be deferred until resources allow.
Source: Google Search Central
robots.txt rules are standardized as RFC 9309. The most specific (longest) matching rule applies, and crawlers may cache the file for up to 24 hours.
Source: IETF RFC 9309 (2022)
Google rewards helpful content regardless of how it is produced; using automation to create content primarily to manipulate rankings violates its spam policies.
Google's spam policies define scaled content abuse as generating many pages primarily to manipulate search rankings rather than help users, however they are created.
Source: Google Search Central
WCAG 2.2 requires a contrast ratio of at least 4.5:1 for normal text at Level AA.
Source: W3C
The U.S. Small Business Administration's Office of Advocacy publishes annual small business profiles and frequently asked questions with official counts of U.S. small businesses.
Source: SBA Office of Advocacy
The U.S. Census Bureau publishes quarterly retail e-commerce sales estimates, the official measure of online retail in the United States.
Source: U.S. Census Bureau
Our rules for statistics
- Primary sources first: the study, the standard or the official documentation, not a blog that quoted it.
- Methodology visible: we note sample sizes and dates when the source gives them.
- No orphan numbers: if we cannot trace a statistic to its origin, we do not publish it. During this site's rebuild we removed dozens of claims that failed that test.
- Benchmarks are not forecasts: a study result tells you what happened for those brands, not what will happen for yours.
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