Incorporating Policy Variables in a Model of the World Soybean/Rapeseed Market
证明政策变量可以成功内生化到世界大豆/油菜籽及产品贸易模型中，估计了多国最低价格支持方程，并通过模拟实验表明内生政策模型优于外生处理。
Abstract Policy variables are typically treated as exogenous variables in agricultural commodity models. In this paper evidence that policy variables can be successfully endogenized in a world trade model of the soybean/rapeseed and products market is presented. Minimum price support equations are estimated for U.S., Brazilian, and Japanese soybeans, and EC and Japanese rapeseed. Macroeconomic indicator variables are used to capture the impact of nontariff barriers in Brazil and Japan domestic‐world price link equations. Simulation experiments are conducted which indicate that the model with endogenous policy variables performs well in comparison with a model which treats policy exogenously.