Sources
An entry on this site can only cite a source from this list. It is a hard restriction in the publishing pipeline, not a guideline.
Why a fixed list
The failure mode of a large reference site is a citation that looks authoritative and is not: a blog post repeating another blog post, a vendor page describing its own metric as an industry standard, an AI-generated listicle. Restricting citations to a known list makes that impossible rather than unlikely.
Sources are grouped in tiers, and the tier changes how a claim may be phrased.
Tier 1 — primary documentation
Google's own documentation, help centres and specifications. Only a Tier 1 source supports a sentence that says Google does, requires or ignores something.
- developers.google.com — Google Search Central, the documentation of record for how Search works
- support.google.com — product help centres for Search Console, Analytics, Business Profile and Ads
- search.google.com — the testing tools: Rich Results Test, Search Console itself
- schema.org and w3.org — the specifications behind structured data and HTML
- web.dev — Google's performance and Core Web Vitals documentation
Tier 2 — established industry references
Long-standing publications with named authors and a correction history. They support claims about practice, tooling and observed behaviour — never claims about what Google does internally.
- Moz, Ahrefs, Semrush — tool vendors with substantial reference material. Cited for their own metrics and for methodology, with the vendor named in the sentence.
- Search Engine Land, Search Engine Journal, Search Engine Roundtable — trade press covering announcements and updates
- Screaming Frog, Yoast, BrightLocal — documentation for widely used tools, cited on how those tools behave
How a source is treated in an entry
- A vendor metric is always attributed to the vendor in the sentence itself, not only in the citation.
- A claim about Google's behaviour needs a Google source, or the entry says it is observed rather than confirmed.
- Outbound links are
nofollow noopenerand open in a new tab. None of them are paid, exchanged or requested. - If a source has gone stale or moved, the entry is corrected — tell me and it gets logged.
What is deliberately not on the list
Content farms, AI-generated SEO blogs, ebooks behind a form, agency pages that exist to rank for a service term, and any site that pays for guest posts. If a claim can only be supported from a source like that, the claim does not go in.
Changing the list
Sources are added when a topic genuinely cannot be sourced from the current list, and removed when a publication stops being reliable. The list currently holds 269 approved hosts. Suggest one at vera@growthpedia.org — with the specific entry it would improve.