文档介绍：Ch 1 索洛增长模型 THE SOLOW GROWTH MODEL
§ Some Basic Facts about Economic Growth
1、增长的两大事实——增长理论的主题
(1)总产出及人均产出的增长——历史分析
Average growth rates in the industrialized countries were: higher in 20th century than in 19th century, and higher in 19th than in 18th; while very low before the Industrial Revolution.
Productivity growth slowdown (since early 1970s), but a rebound in the . since 1990s.
(2)增长的差距扩大——横向比较
There are also enormous differences in standard of living across parts of the world. Over the whole of the modern era, specially since 1990s, cross-country e difference have widened on average.
Divergence vs Convergence
Growth Miracles: NICs of East Asia
Growth disasters: Argentina, Mexico,
Sub-Saharan Africa
2、二战后增长理论的演进
(1)第一代增长理论——Harrod-Domar Model (1948)
结论:唯有资本积累重要。
(2)第二代增长理论—Solow Model(Ch 1)
模型假定:a. Exogenous saving rate and
technological progress
b. Decreasing returns to capital
结论:资本积累的作用有限,技术进步是决定性因素。
(3)第三代增长理论—New Growth Theory
Ch2: Ramsey and Dimond Model: Endogenous saving rate;
Ch3: New Growth Theory: Endogenous tech. progress
结论:技术进步与生产率的提高是内生的,取决于
R&D投资,制度和政策环境等因素。
§ Assumptions
1、总量生产函数:
AL: Effective labor
2、Constant returns to scale(CRS):
暗含假定:无分工的收益;不考虑其它要素的贡献
F(cK, cAL)=cF(K, AL) ()
A: Knowledge or effectiveness of labor
or Y=AF(K, L) Hicks-neutral
Y=F(A·K, L) Capital augmenting
Labor-argmenting or Harrod-neutral
3、劳均生产函数(每个有效劳动单位AL):
4、Cobb-Douglas Production Function:
5、Evolution of the inputs into production
(1)假定劳动和技术的增长率外生,且为自然增长率;
同理
(2)资本的增长率:假定储蓄率是外生的,且保持不变
6、其它假定: Solow 模型所忽略的因素(P13下-14上)
(1)只有一种商品(商品同质),所以生产函数可加总;
(2)无政府的作用,G=0,T=0;
(3)不考虑就业波动,假定AS=AD,即充分就业假定;
(4)生产只有三种投入:K,L,A;
(5)s, δ, n, g 均为常数。
§ Solow Model
1、The Dynamics of k
推导:()和()