理解商业周期:基于稳定和非稳定机制的视角

Understanding Business Cycles:Perspective from Stabilizing and Destabilizing Mechanism

本文将从稳定和非稳定机制的视角来讨论经济波动和商业周期现象。在我们承认价格调整这一稳定机制存在的同时,经济体内是否还存在着其他机制以破坏经济的稳定?早在1939年,哈罗德就已经通过刀刃问题揭示了非稳定机制的存在——企业的投资行为。为此,本文构建了以价格和投资为核心变量的宏观动态模型,即以龚刚、林毅夫(2007)所构建的投资优化模型为基础,引入投资函数;与此同时,在新凯恩斯主义粘性价格理论的基础上,构建了价格方程。研究表明,经济的稳定机制(价格行为)和非稳定机制(投资行为)的相互作用使经济产生了波动。进一步的研究发现,由于价格调整具有粘性,其作为对经济的一种稳定机制,有可能不足以使得经济稳定。此时,另外一种稳定机制,即政府的宏观稳定政策就成为必要。

We study economic fluctuation and business cycles from the perspective of stabilizing and destabilizing mechanism. While recognizing the existence of price adjustment as a stabilizing mechanism, whether there exist other mechanisms to destabilize the economy？ We find that as earlier as in 1939, Harrod had already proved the existence of destabilization mechanism--the firm＇s investment adjustment--by showing the knife-edge problem. For this, we construct a macro-dynamic model with investment and price as core macroeconomic variables： the investment function introduced in this model is derived from the investment optimization model constructed in Gong ＆ Li （2007） ; a dynamic optimization model is also constructed to derive the price function by following the sticky pricing of new Keynesian. Analysis shows that the interaction between stabilizing mechanism （price adjustment） and destabilizing mechanism （investment adjustment） generates fluctuation and business cycles for the economy, Yet, due to the sticky adjustment, the price adjustment as a stabilization mechanism may not be sufficient for the economy to be stabilized. In this case, the stabilization from government policy may become necessary.