Economist Wojtek Kopczuk asked ChatGPT to calculate tariffs to balance out the U.S. trade deficit. He received a similar answer to the White House’s documentation, showing the AI used “a basic approach” that divided the trade deficit by the total trade. Entrepreneur Amy Hoy ran a similar experiment, yielding identical results from AI models.

The Trump administration took that formula’s figure, -0.5 for South Korea, and divided it by two to calculate the U.S. “discounted reciprocal” tariff rate. So, while South Korea imposes an effective tariff rate of .79 percent on U.S. goods, the reciprocal tariff rate the U.S. is imposing on South Korea is 25 percent.

The Trump administration's formula for calculating new tariffs raised questions among economists — even some whose work was cited.