本地市场效应:理论和经验研究的新近进展

本地市场效应是指,在一个存在报酬递增和贸易成本的世界中,那些拥有相对较大国内市场需求的国家将成为净出口国。它源自新古典贸易理论解释复杂贸易实践的理论局限和新贸易理论经验证据匮乏的困境,在探寻两种理论范式相对解释力的过程中应运而生,并随着空间经济学的迅猛崛起而成为新经济地理范式(New Economic Geography Paradigm)的核心特征之一。本文在回顾本地市场效应的理论背景和基本理论模型的基础上,对其理论模型和经验证据的新近发展作了系统的梳理并进行了简要的评论。     

FORECASTING AND POLICY EVALUATION IN ECONOMIES WITH RATIONAL EXPECTATIONS: THE DISCRETE TIME CASE*

Several techniques for solving dynamic rational expectations models have been proposed. This paper puts forward an alternative method for discrete time models, which is significantly simpler to use in practice. That solution is used to derive and compute optimal policy selections (incorporating ‘noncausal’ effects) which, by exploiting the discrete time framework, are also time consistent when sequentially reoptimized. Those decisions are shown to contain an optimal open loop component plus an innovations dependent correction mechanism. A numerical example is used to verify these properties, and to demonstrate the superiority of this policy selection technique over recursive methods (e.g. dynamic programming).