WASHINGTON: A top trade analyst has said the Trump administration's calculations that led to the tariffs are “not standard economics” and in many cases impose rates far higher than those that the targeted countries apply to US goods.

Julia Spies, chief of trade and market intelligence at the International Trade Center, said uncertainties remain about the exact way the US Trade Representative's office and other US officials came up with the tariffs.

She said the figures presented by Trump roughly match the US trade balance — or imbalance — with a specific country, divided by imports from that country, “and that, divided by two, gives us the reciprocal tariff” imposed by the US.

“This is not standard economics,” Spies told reporters by video to a UN briefing in Geneva.

The US calculation included countries' tariffs on American exports plus other regulations and policies in those countries, like currency manipulation, sanitary measures, and technical barriers to trade, and “all of that led to this – what they call tariffs'.”

The ITC, based in Geneva, is a joint agency of the United Nations and the World Trade Organisation that aims to help small businesses in the developing world to trade.