In contrast, the United States produces most of its resources, partly as a result of the shale revolution, and thus a rise in commodity prices does not necessarily lead directly to an outflow of income from the country. An indicator of national income that also takes into account changes in the terms of trade is called real gross national income (GNI).
This is calculated by adding up real GDP, net income from the rest of the world -- such as foreign investment income -- and trading gains and losses, which represent the change in income due to changes in the terms of trade that are mainly brought about by movements in commodity prices.