Editorial standards

Last updated 22 October 2026.

Primary sources first

Articles are written from primary documents (treaties, laws, government and archive records such as the US National Archives and the Avalon Project at Yale), official statistics (World Bank, United Nations agencies, national statistics offices) and peer-reviewed or open-access scholarship cited by DOI. News stories, videos and other blogs may tell us what people are curious about, but they are never used as the source of a fact, and their text and images are not reproduced.

A source for every number

Every figure in an article, such as a date, distance, population or amount of money, can be traced to a source in the article's Sources list. Where we convert a unit or round a number, the article says so. Each article shows the date its sources were last checked.

Evidence and disagreement

Each article separates what the records show from what is interpretation. When historians or economists disagree, we describe each position and cite it, and we say where the evidence is thin.

What we do not do

• No sensational headlines. Titles are the question the article answers.
• No forecasts of ongoing wars, invasions or elections, no conspiracy theories, and no content that disparages any people, ethnicity or nation.
• No details we could not confirm from a primary record; if a key detail could not be checked, the article says so.
• No images copied from videos or other sites. Diagrams are drawn for this site; any third-party image is public domain or openly licensed and credited.

Corrections

If an article contains an error, we correct it in the text, update the 'sources checked' date and note what changed at the end of the article. Report errors through the contact page, ideally with the source that shows the correct information.