U.S. Secretary of Agriculture Sonny Perdue released a detailed accounting of how the U.S. Department of Agriculture 
(USDA) calculated estimated damage from trade disruptions. USDA’s Office of the Chief Economist developed an estimate of gross trade damages for commodities with assessed retaliatory tariffs by Canada, China, the European Union, Mexico, and Turkey to set commodity payment rates and purchase levels in the trade mitigation package announced by USDA on September 4, 2018. USDA employed the same approach often used in adjudicating World Trade Organization trade dispute cases.
“We have pledged to be transparent about this process and how our economists arrived at the numbers they did,” Perdue said. “Our farmers and ranchers work hard to feed the United States and the world, and they need to know that USDA was thorough, methodical, and as accurate as possible in making these estimates. It was a large and important task, and I thank Chief Economist Robert Johansson and his staff for their hard work.”
The full description of the Trade Damage Estimation for the Market Facilitation Program and Food Purchase and Distribution Program is available on the website of USDA’s Office of the Chief Economist.
Source: USDA