How this site is researched

This page describes the editorial process behind every page on CanonicalTag.com: where the facts come from, how they are checked, how pages are dated, and what happens when sources disagree. It exists because a reference is only as useful as a reader's ability to check it.

Sources

Research for each page is gathered before any writing starts and recorded in a research file for that page. The sources, in order of preference, are Google Search Central documentation and the Search Central blog, Search Console Help, Bing Webmaster guidance, the relevant standards (RFC 6596 for the canonical link relation, RFC 8288 for web linking, the WHATWG HTML standard), each platform's official documentation, and on-record statements by Google staff with a link to where they were made. SEO publications are used only as secondary sources and are labeled as such in the research.

How a page is written

Each page is written from its own research file and a written brief that sets its subject, the answer it must lead with, and the subjects that belong to other pages. The rule for the writing is that a fact must come from the research: setting names, menu paths, function names, dates and quotations are traced to a document, and anything the sources do not settle is either hedged in the text or left out. Pages lead with a short verdict so a reader gets the answer before the explanation.

Review before publishing

Before a page is published it is checked against its sources and run through automated checks for broken links, accessibility, heading structure, duplicated passages, spelling, and whether the page's figures appear in its research at all. A record of which research file each page was written from is kept with the site's project files.

Dates

A page's published date is set when it first goes live and never moves. The updated date changes only when the page's written content changes, not when the site's design or navigation does, so an "updated" date on this site means the words on the page changed.

When sources disagree

Google's documentation, statements by Google staff and observed behavior do not always agree, and some guidance has changed over time (rel=prev/next and the retired Search Console preferred-domain setting are two examples). Where that happens, the page says so, gives the dates, and describes what can be relied on rather than picking a side it cannot support.

Corrections

Corrections are welcome and are made to the page itself, which then carries a new updated date. Use the contact page, and include the source that shows the change.