现代宏观经济学中的投资理论及其最新发展

一、引言现代宏观经济学中投资理论的发展大致经历了三个阶段 :第一个阶段的理论被称之为新古典(ｎｅｏｃｌａｓｓｉｃａｌ)投资理论 ,是以Ｊｏｒｇｅｎｓｏｎ(1 96 3,1 96 9)为代表的经济学家们在 6 0年代发展起来的 ,严格地说 ,新古典投资理论描述的是稳定状态下的理想资本水平及其决定因素之间的关系 ,其中的主要变量是产出和资金的使用成本。第二阶段以ｑ 理论 (ｑ ｔｈｅｏｒｙ)的形成为标志。由于托宾 (Ｔｏｂｉｎ ,1 96 9)首先提出这个想法 ,所以又称 ｑ为Ｔｏｂｉｎ’ｓｑ .ｑ 理论的严谨模型是在 70年代后期和 80年代初建立起来的 …

The Investment Theory in Modern Macroeconomics and Its Newest Development

This article reviews the development process of the investment theory in rnodern macroeconomics,and it gives priority to introduce the important progress of the investment theory in the recent decade.The standard neoclassical investment theory lays special stress on describing investment decision\|making, so it does not consider any adjustment costs of investment in addition to the price or cost of capital goods bought or leased.The q\|theory assumes that adjustment costs of investment is the convex function of investment amount,i.e. the bigger the investment amount,the higher the marginal adjustment costs.In most empirical studies this adjustment cost function adopts the form of quadratic function.Finally,the newest development of investment theory\_the theory of irreversible investment\_stresses the constant cost of investment adjustment,and thus it has inferred and extended a series of new theories and new views.The approach of the theory of irreversible investment has more general significance,and it is practically a special example of the optimal new microeconomic pattern.