Sources
Every figure and claim on this site traces back to one of the datasets below. Official statistics and self-reported survey answers are never mixed in the same ranking, and every counted figure here is live, pulled straight from the database.
| Source | What it provides | Tier | Refresh |
|---|---|---|---|
| OECD Revenue Statistics (Global) | Tax-to-GDP and the full tax mix by category and level of government | Official statistics | Refreshed by the data pipeline |
| World Bank / IMF GFS | Central-government tax revenue for jurisdictions the OECD set does not cover, labelled separately because the definition is narrower | Official statistics | Pipeline |
| IMF / OECD / CIAT / IOTA ISORA | Administrations’ self-reported operational data: audit activity, automated compliance checks, third-party data systems, penalties, staffing | Self-reported survey | Pipeline |
| OECD Inventory of Tax Technology Initiatives (ITTI) | Administrations’ self-reported technology use, including artificial intelligence | Self-reported survey | Pipeline |
| OECD Corporate Tax Statistics (QDD) | CFC rules, interest limitation, country-by-country reporting and IP regimes, including the OECD’s own description of each regime | Official statistics | Pipeline |
| OECD effective tax rates | Effective corporate tax rates | Official statistics | Pipeline |
| OECD Global Forum CARF commitment list | Which jurisdictions have committed to crypto-asset reporting and by when | Official | Pipeline |
| PwC Worldwide Tax Summaries | Headline statutory rates and the basis of individual taxation, quoted verbatim | Professional analysis | Pipeline |
| National tax authority annual reports | Audits, compliance yield, prosecutions and tax gap as each authority states them | Official | Annually, as each authority publishes |
| National legislation and authority guidance | The statutory basis for individual enforcement powers, quoted verbatim | Official | Re-verified weekly |
Bulk-dataset timestamps: OECD tax-to-GDP and structure data last fetched 2026-08-16, ISORA last fetched 2026-08-16, ITTI last fetched 2026-08-13, anti-avoidance regimes and effective tax rates last fetched 2026-08-13.
How often it changes
A weekly re-verification job re-fetches every quoted source and withdraws any claim whose quote no longer matches character for character. The data pipeline separately re-pulls the bulk datasets above on their own schedules. A daily database backup runs regardless of whether either job finds anything to change.
Known gaps
Some authority sites block automated access; those sources are recorded as blocked rather than worked around. Several jurisdictions have no assessed powers yet and are excluded from the sitemap until they do.