The categories of evidence this site relies on, in order of weight, and what happens when a figure can't be confirmed.
Every entry in the record and every case under American support is held to the four tests set out under editorial position: a specific date, named people or institutions, a figure a reader can independently check, and a source listed at the bottom of the entry. Where a figure could not be confirmed against a primary document, it has been removed rather than rounded off and kept — several entries carry an editorial note saying exactly that.
Public laws as enacted, cited by Public Law number, and executive orders as published in the Federal Register — for example the Chinese Student Protection Act of 1992 or Executive Order 13936.
Case filings, sentencing memoranda and Department of Justice press releases tied to a specific docket.
Government Accountability Office reports, Congressional Research Service reports, and agency publications such as the State Department's annual International Religious Freedom Report.
Treaties and joint declarations registered with the United Nations or otherwise publicly filed, such as the Sino-British Joint Declaration of 1984.
Used only where the documentary record is thin — individual named cases, for instance — and flagged as such rather than presented as equivalent to a primary document.
Several entries on this site were tightened during a sourcing review: unsupported figures were removed rather than softened with words like "roughly" or "estimated." Where that happened, the entry's own sourcing note says so by name. Report a figure you believe is wrong through contact, with what you believe the correct source shows.