文档介绍：CHAPTER 3 NEW GROWTH THEORY
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SOME BASIC INFORMATION
(1)If r=f '(k), and αk is modest, then capital accumulation cannot account for a large part of either long-run or cross-country e differences.
(2)The effectiveness of labor (A) is the only determinant of e, whose behavior is taken as exogenous.
(3)The effectiveness of labor (A) is explicitly interpreted as knowledge, and knowledge accumulation is endogenous.
(4) Knowledge accumulation is probably central to worldwide growth.
(5)Much of the variation in e across es from differences in output for given amounts of physical and human capital.
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Part A Research and Development Models
§ Framework and Assumptions
Assumptions
(1)The effectiveness of labor (A) represents knowledge or technology, there are two sectors, an R&D sector; a goods-producing sector.
(2)Two other major simplifications:
First, both the R&D and goods production function are C-D function; second, the model takes the s, αK and αL as exogenous and constant.
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Assumptions
(3) Fraction ak of the capital stock is used in the R&D sector and fraction 1- ak in the goods-producing sector; fraction aL of the labor force is used in the R&D sector and fraction 1- aL in the goods-producing sector.
(4)The quantity of output produced at time t is thus:
物质生产部门的生产函数
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知识生产部门的生产函数
知识生产部门的生产函数取消了报酬不变的假定,
因而可能存在报酬递减或报酬递增两种可能性。
The parameter θ reflects the effect of the existing
stock of knowledge on the ess of R&D
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(5)As in the Solow model, the saving rate is exogenous and constant, depreciation is set to zero.
(6)Population growth is treated as exogenous.
(7)Without capital for the moment. α=0,β=0
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§ The model without capital
The production for output es:
The production for new knowledge is now:
We then focus on the dynamics of A:
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Taking logs of both sides, then
differentiating the two sides with
respect to time t, yields:
θ>1 or θ<1 or θ=1
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