President Donald Trump announced an aggressive, far-reaching “reciprocal tariff” policy this week, leaving many economists and U.S. trade partners to question how the White House calculated its rates.

Trump’s plan established a 10% baseline tariff on almost every country, though many nations such as China, Vietnam and Taiwan are subject to much steeper rates. At a ceremony in the Rose Garden on Wednesday, Trump held up a poster board that outlined the tariffs that it claims are “charged” to the U.S., as well as the “discounted” reciprocal tariffs that America would implement in response.

Those reciprocal tariffs are mostly about half of what the Trump administration said each country has charged the U.S. The poster suggests China charges a tariff of 67%, for instance, and that the U.S. will implement a 34% reciprocal tariff in response.

However, a report from the Cato Institute suggests the trade-weighted average tariff rates in most countries are much different than the figures touted by the Trump administration. The report is based on trade-weighted average duty rates from the World Trade Organization in 2023, the most recent year available.

The Cato Institute says the 2023 trade-weighted average tariff rate from China was 3%. Similarly, the administration says the EU charges the U.S. a tariff of 39%, while the 2023 trade-weighted average tariff rate was 2.7%, according to the report.

In India, the Trump administration claims that a 52% tariff is charged against the U.S., but Cato found that the 2023 trade-weighted average tariff rate was 12%.

Many users on social media this week were quick to notice that the U.S. appeared to have divided the trade deficit by imports from a given country to arrive at tariff rates for individual countries. It’s an unusual approach, as it suggests that the U.S. factored in the trade deficit in goods but ignored trade in services.

The Office of the U.S. Trade Representative briefly explained its approach in a release, and stated that computing the combined effects of tariff, regulatory, tax and other policies in various countries “can be proxied by computing the tariff level consistent with driving bilateral trade deficits to zero.”

“If trade deficits are persistent because of tariff and non-tariff policies and fundamentals, then the tariff rate consistent with offsetting these policies and fundamentals is reciprocal and fair,” the USTR said in the release.