Approximating the Effective Protection Coefficient without Reference to Technological Data
提出一种在缺乏投入产出技术数据时近似计算有效保护系数的方法，利用四种农产品的截面数据推导近似方程，仅需名义保护系数和宏观数据，经样本外检验表现良好。
When proposals for reform of tariff or subsidy policies are made, attempts to predict the effect on incentives are frequently hampered by the need for input-output technical data. This article develops and illustrates the use of a methodology for approximating effective protection coefficients (EPCS) when such data are unavailable or outdated. It derives the equations which approximate the EPC from statistical analysis of a cross section of existing EPC studies for four agricultural commodities: corn, cotton, rice, and wheat. Informational requirements for computing approximations include the nominal protection coefficients on output and tradable inputs and readily available macroeconomic data. These approximation equations perform well in an out-of-sampl'e test. Trade economists are constantly in search of empirical measures of the sectoral production incentives introduced by government trade, exchange rate, and input pricing policies. The effective protection coefficient (EPc), which is the ratio of domestic to world value added, is commonly accepted as the preferred metric for this purpose, despite its well-known drawbacks (Dixit 1985). EPCs