Excerpt from the booklet: Governments use a variety of policies to achieve their agricultural goals. Many policies are, in effect, subsidies or taxes on producers or consumers. Regardless of the form of these policy interventions, they nearly always have some distorting effect on trade among nations. Aggregate measures of support, such as the producer subsidy equivalent and the consumer subsidy equivalent, may help negotiators of a new GATT attain common ground for reducing barriers to international trade.