Methodology

How we verify tax data

Every quantitative claim on Tax Atlas is a single database record with a source and a date. This page explains where that data comes from, how sources are ranked, and how often it is checked.

Source hierarchy

We prefer primary sources in this order: (1) the law or statute itself, (2) the national tax authority, (3) the OECD and tax treaties, (4) the major professional summaries (e.g. PwC Tax Summaries). Each fact records the source URL, publisher, source type and the date it was accessed.

Verification and signature

A first draft of country data is compiled from primary sources, then reviewed and signed off by a licensed accountant before publication. The page shows the verifier and the date — the “Last verified” line is both the strength and the standing commitment.

Update cadence

Sources are monitored for changes; when a rule actually changes, the fact and its verification date are updated and the change is logged. Dates are never bumped without a real change — false freshness is not verification.

Quality gate

A country or comparison page is published only when it clears a minimum threshold of filled, sourced facts. Pages below the bar do not exist — thin, unsourced pages are never published.