| 摘要:根据新古典增长理论,存在一个稳态黄金储蓄率,在这一储蓄率下,社会消费(生活水平)达到最大化。其条件为“去除折旧的有效率人均资本存量的边际产量等于经济增长率”。黄金储蓄率的实现与否,可以作为产业结构分析的理论依据。即:资本去除折旧的净边际产量若大于经济增长率,说明产业结构中,用于生产资料生产的产业布局(投资)及出口加工业的产业布局过少。用这样的分析框架对我国总体及东、中、西部地区的产业结构的分析显示,全国的产业结构中生产资料的生产比例总体不足,资本报酬占其总产值的比例在全国地区间差异较大,北京由于2008奥运已使生产资料生产产业布局过高。 关键词:索罗模型 新古典分配理论 产业结构 An Analytical Framework on Industrial Structure under Solow Model —Positive Analysis of China
Abstract: according to neo-classical economic growth theory, there is a golden rule steady state of saving rate under which the consumption may be maximized, and so were the living standard. This golden rule steady state of saving rate is the case that marginal products of capital stock per effective worker net of depreciation equals the growth rate of the economy. By the definition of saving rate, and the neo-classical growth theory, that whether the golden rule steady state of saving rate is currently achieved or not might be applied to be the framework of analyzing the structure of industry. That is, if the marginal product of capital stock per effective worker net of depreciation is greater than the growth rate of the economy, then the saving rate, which is composed of capital good production and net export (net foreign investment), would be much less than the optimal structure. With this principle, I examined the industrial structure of China and its different regions. The conclusions are that, China as a whole, the proportion of capital good production industry is less than the optimal structure, and that the proportion of the returns of capital in China varies regionally. Beijing’s capital good production industry is the exception, largely due to the 2008 Olympic Game.
Key words: Solow Model, neo-classical distribution, industrial structure 将索罗模型(Solow Model)用于产业结构的分析中,文献中少见报道,本文试图通过对索罗模型的分析,提出一个产业结构分析的框架,并对我国总体及东、中、西部地区产业结构进行分析。 一、新古典经济增长理论回顾 索罗(Solow)的新古典经济增长理论认为,经济增长由有效率的人均资本存量(capital stock per effective worker)的增长产生,有效率的人均资本存量会出现稳态(steady state),在稳态时,只要储蓄率不变,有效率的人均产出就会固定下来,不再变化,此时的人均经济增长率等于技术进步率。基本模型如下: 生产函数满足规模报酬不变(constant returns to scale),要素的边际产量递减。对于劳动力投入量L(t),资本投入量K(t),劳动力的效率(efficiency of worker, E(t))及其增长率(labor-augmenting technological progress, g)的生产函数,其表达式为:
其中F(×)表示生产函数关系。由于规模报酬不变,则有效率的人均劳动力(effective worker per unit of labor)的产出为
其中y=Y/EL,k=K/EL分别表示有效率劳动力的人均产出和有效率劳动力的人均资本存量,f(×)为F(×)的强化式。索罗理论认为,资本存量的变化主要由新增资本投资和资本折旧构成,新增资本投资恒等于产出减消费,或储蓄率(s)与产出的乘积,索罗模型可表示为
y*(t)为稳态时,有效率的劳动力的人均产量(收入)。k*为稳态时有效率劳动力的人均资本存量。由于稳态时,有效率的人均资本存量不变,由式(1.6)可知,储蓄应该有三个方面的用途,以保持稳态,即:为新增加的劳动力提供资本;为技术进步(提高劳动力劳动效率)提供资本;弥补资本折旧。由生产函数可知,稳态时有效率的人均产量也不变,即:
由(1.6)式可知,稳态时有效率的人均劳动力的资本存量及稳态时的有效率的人均总产出是储蓄率等变量的函数。(1.11a)可以写成
MPK为边际资本产量,(1.12a)的含义为其他变量不变的情况下,储蓄率的变化对消费有影响,且存在一个消费极值,在某一储蓄率下,消费最大化。此储蓄率被定义为资本存量的黄金稳态水平(Golden-Rule level of the capital stock)储蓄率。(1.12b)的含义为在黄金稳态储蓄率下,资本去除折旧的净边际产量(marginal product of capital net of depreciation)等于经济增长率。
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