How we know this, and how you can check

A claim about tax is only as good as the source under it. So we put the source under all of them, and we show our working where the numbers are ours.

This site makes a lot of numerical claims. Here is the standard every one of them has to meet.

Primary sources only. Tax rates come from the tax authority that sets them: HMRC, the IRS, the Canada Revenue Agency, the Australian Taxation Office, India's Income Tax Department. Estimates of revenue lost to avoidance come from the bodies that produce them: the OECD, the Tax Justice Network, the IMF, national audit offices, and peer-reviewed research. Where a figure is a single study or a campaign estimate rather than an official statistic, we say so.

Dated, because tax moves. A rate that was right last year may be wrong this year. Every figure carries the year it applies to. When a country changes a rule, we change the page.

Comparisons shown both ways. When we say a small firm pays a higher rate than a giant, we show the small firm's all-in rate and its corporation-tax-only rate, because the honest comparison is the corporation-tax-only one. And we never compare a company's global rate to a single country's without saying that is what we are doing. Those two moves are exactly how a misleading tax comparison is built, so we refuse to build one.

The working is yours. Where a number is our own calculation, the inputs and the method sit on the page, so a sceptical accountant can rebuild it. Where it is someone else's, the link goes to the original. If you find one that does not hold up, we want to know.

We would rather be slow and right than fast and quotable. The point of the site is that you can trust the maths, so the maths has to earn it.