Sources Policy

Last updated: 12 November 2026

Readers should be able to check everything we publish. This policy explains which sources we trust, how we cite them, and what we will never treat as a source.

What counts as a reliable source

We build profiles from sources with a reputation for accuracy and editorial oversight. Depending on the subject, that includes:

• Reference works such as Encyclopaedia Britannica and other established encyclopaedias.
• Official records and institutional sources — NobelPrize.org for laureates, the Library of Congress, NASA, the Royal Society, Olympics.com, FIFA and the ICC for sports figures, and official foundation, estate and government pages.
• Reputable news organisations and established historical publications, used with care and cross-checked.
• Specialist sources for a field, such as the Poetry Foundation for poets and the BFI for filmmakers.

Primary sources — a person's own writings, speeches and official records — are used wherever they are available and relevant, and are cited as such.

Wikipedia: a starting point, never the sole source

Wikipedia is a useful starting point and a cross-check, but it is never the sole source for a fact on this site. Every key fact must also be confirmed by at least one independent reliable source, and every profile lists at least three independent sources in total. Our Fact-Checking Methodology explains the verification process in full.

What we do not use as sources

We do not cite social-media posts, fan pages, content farms, AI-generated articles or unattributed listicles as evidence for a fact. We do not treat a claim as verified because it appears on many sites, if those sites all repeat the same single origin. And we do not use a source that contradicts itself without noting the contradiction — where sources disagree, the profile shows both sides, as explained in our Editorial Policy.

How we cite

Every profile page ends with a list of its sources, so readers can follow any fact back to where it came from. Key facts, dates and quotations are tied to the sources that support them, and disputed claims are labelled with both perspectives. We paraphrase and cite sources; we do not copy copyrighted text. Where a source is a copyrighted work, such as a NobelPrize.org laureate record, we use it as a reference for facts and never reproduce its text.

Source quality by subject

Different subjects need different sources. A scientist's achievements are checked against institutional and academic records; an athlete's against official sporting bodies; a writer's against literary references and their published works. If the reliable sources for a subject are thin, the profile says so — the page shows "Not reliably documented" for anything that cannot be established, rather than padding the biography with weaker material.

Suggesting a source or reporting a problem

If you know of a reliable source we have missed, or you believe a source we cite is wrong or has been superseded, please email [email protected]. Source suggestions are treated like corrections: they are logged, checked, and acted on when verified — see our Corrections Policy. You can also reach us through our Contact page, and read more about the site on the About page.