Scale effects in endogenous growth theory an error of aggregation not specification
经济学名词解释：外生经济增长和内生经济增长理论
经济学名词解释：外生经济增长和内生经济增长理论对经济增长的研究, 可以从不同的方面进行, 从而形成各有侧重的经济增长理论。
对现代增长理论的重新思考, 源自所谓外生增长和内生增长之间的差别。
外生经济增长理论认为经济增长是由经济理论不能预见的所谓外生的技术进步推动。
而内生经济增长理论是指不依赖经济外部的力量(如外生的技术进步、外资等) 的推动, 主要由经济的内在力量(如内生的技术变化、资本积累等) 推动的长期经济增长。
因此, 现代经济增长理论的研究大体上可以作这样一个划分: 一类是将技术当成是外生变量的经济增长理论, 以罗伯特•索洛(R. M. Solow) 为代表: 另一类是将技术当成是内生变量的经济增长理论, 主要是80 年代以来保罗•罗默(P. Romer) 等人的新经济增长理论为代表。
外生经济增长理论外生经济增长理论认为经济增长是由经济理论不能预见的所谓外生的技术进步推动。
古典经济增长理论的古典增长模型和哈罗德—多马经济增长模型都已经做了不少研究。
对影响经济增长的各种力量以及决定增长过程的机制做出说明。
他们认为, 经济增长取决于投资的规模和资本产出率的大小, 而投资来源于储蓄, 因而经济增长最终由一国的储蓄率与资本的投资效率决定。
后来, 索洛等人提出一个强调技术进步的经济增长论。
他们区分经济增长的两种不同的来源: 由要素数量增加而产生的“增长效应” (Growth Effect) 和因要素技术水平提高而带来的经济增长。
索洛把后者称之为“水平效应” (Level Effect) 。
其含义是指在不增加要素投入的情况下, 技术进步可以通过改变生产函数, 从而使生产函数向上移动, 达到经济增长的目的。
所以, 外生经济增长理论认为经济增长是由经济理论不能预见的所谓外生的技术进步推动。
索洛模型, 由索洛和斯旺(T. W. Swan) 于1956 年作出。
索洛模型以其简洁性和实用性成为宏观经济学家工具箱中不可缺少的工具, 经济学家在回答有关经济增长的问题时, 通常都从索洛模型开始。
所有发在AEJ系列上关于中国问题的文章信息!未曾想影响力最大的竟是国外学者写的！
所有发在AEJ系列上关于中国问题的文章信息!未曾想影响力最大的竟是国外学者写的！邮箱：***********************所有计量经济圈方法论丛的code文件, 微观数据库和各种软件都放在社群里.欢迎到计量经济圈社群交流访问.今天，整理了所有发表在American Economic Journal系列期刊上关于中国问题的文章。
值得注意的是，由于推文版面限制，考虑到一些文章有很多作者，因此我们省略了作者信息。
此外，凡是中国学者参与写作的，不管是不是关于中国问题的文章，我们也将其统计在这个系列里面。
中国内陆学者参与的写作的文章文章名称期刊年份被引Industrial Policy and Competition AEJ-MACROECONOMICS2015104Trade Liberalization and Markup Dispersion: Evidence from China's WTO Accession AEJ-APPLIEDECONOMICS201593The Great Housing Boom of China AEJ-MACROECONOMICS201776Domestic Institutions and the Bypass Effect of Financial Globalization AEJ-ECONOMICPOLICY201054Place-Based Policies. Creation, and Agglomeration Economies: Evidence from China's Economic Zone Program AEJ-ECONOMICPOLICY201950How Do Tax Incentives Affect Investment and Productivity? Firm-Level Evidence from China AEJ-ECONOMIC POLICY2019 40 Health, Height, Height Shrinkage, and SES at Older Ages: Evidence from China AEJ-APPLIED ECONOMICS 2013 40 Did Bankruptcy Reform Cause Mortgage Defaults to Rise? AEJ-ECONOMIC POLICY 2011 30 Firm Heterogeneity and the Long-run Effects of Dividend Tax Reform AEJ-MACROECONOMICS2010 26 Input and Output Inventory DynamicsAEJ-MACROECONOMICS2011 20 The Effect of Market Structure on Cellular Technology Adoption and Pricing AEJ-MICROECONOMICS 2011 18 The Power of Social Pensions: Evidence from China's New Rural Pension Scheme AEJ-APPLIED ECONOMICS 2021 13 Amplification and Asymmetric Effects without Collateral Constraints AEJ-MACROECONOMICS 2017 13 The Marginal Cost of Traffic Congestion andRoad Pricing: Evidence from a NaturalExperiment in BeijingAEJ-ECONOMICPOLICY202011Does Teacher Training Actually Work? Evidencefrom a Large-Scale Randomized Evaluation of aNational Teacher Training ProgramAEJ-APPLIEDECONOMICS2019 11 The Impact of Investment Incentives: Evidence from UK Corporation Tax Returns AEJ-ECONOMIC POLICY2019 9 The Economics of NationalismAEJ-ECONOMICPOLICY2015 9 There Will Be Killing: Collectivization and Death of Draft Animals AEJ-APPLIED ECONOMICS 2017 8 Rising Intergenerational Income Persistence in China AEJ-ECONOMIC POLICY 2021 8 A Pseudo-Market Approach to Allocation with Priorities AEJ-MICROECONOMICS 2018 8 College Admission with MultidimensionalPrivileges: The Brazilian Affirmative ActionCaseAEJ-MICROECONOMICS2021 5 Subways and Road CongestionAEJ-APPLIEDECONOMICS2021 4 Foreign Rivals Are Coming to Town: Responding to the Threat of Foreign Multinational Entry AEJ-APPLIED ECONOMICS 2018 4 Consumption Insurance against Wage Risk:Family Labor Supply and Optimal ProgressiveIncome TaxationAEJ-MACROECONOMICS2021 4 Security Price Informativeness with Delegated Traders AEJ-MICROECONOMICS 2010 3 Utilitarian Aggregation with Heterogeneous Beliefs AEJ-MICROECONOMICS2021 2 The Out-of-State Tuition DistortionAEJ-ECONOMICPOLICY2019 2 Interest Rate Liberalization and Capital Misallocations AEJ-MACROECONOMICS20212Hometown Ties and the Quality of GovernmentMonitoring: Evidence from Rotation of ChineseAuditorsAEJ-APPLIEDECONOMICS2021 2The Size Distribution of Firms and IndustrialWater Pollution: A Quantitative Analysis ofChinaAEJ-MACROECONOMICS2021 1Communication Infrastructure and StabilizingFood Prices: Evidence from the TelegraphNetwork in ChinaAEJ-APPLIEDECONOMICS2021 1 Capital Markets in China and Britain, 1770-1860: Evidence from Grain Prices AEJ-APPLIED ECONOMICS2021 1 Vertical Agreements and User AccessAEJ-MICROECONOMICS2021 0 The Economics of Speed: The Electrificationof the Streetcar System and the Decline ofMom-and-Pop Stores in Boston, 1885-1905 AEJ-APPLIEDECONOMICS2021 0 Reducing Frictions in College Admissions: Evidence from the Common Application AEJ-ECONOMIC POLICY2022 0 Orchestrating Information AcquisitionAEJ-MICROECONOMICS2021 0 Knowledge Diffusion, Trade, and Innovation across Countries and Sectors AEJ-MACROECONOMICS2022 0 Dominated Options in Health Insurance PlansAEJ-ECONOMICPOLICY2022 0 Did Unconventional Interventions Unfreeze the Credit Market? AEJ-MACROECONOMICS 2020 0 A Theory of Organizational Dynamics: Internal Politics and Efficiency AEJ-MICROECONOMICS2018中国香港学者参与的写作的文章文章名称期刊 年份 被引Place-Based Policies. Creation, andAgglomeration Economies: Evidence from China's Economic Zone ProgramAEJ-ECONOMICPOLICY2019 50Credit Constraints and Self-Fulfilling Business Cycles AEJ-MACROECONOMICS2014 39 Speculative Bubbles and Financial Crises AEJ-MACROECONOMICS2012 33Sharing the Burden: Monetary and Fiscal Responses to a World Liquidity Trap AEJ-MACROECONOMICS 2013 24 Risk-Sensitive Consumption and Savings under Rational Inattention AEJ-MACROECONOMICS 2010 15The Comparative Statics of Optimal Hierarchies AEJ-MICROECONOMICS 2019 14 Do College Graduates Serving as Village Officials Help Rural China? AEJ-APPLIEDECONOMICS 2017 13Aid, China, and Growth: Evidence from a New Global Development Finance Dataset AEJ-ECONOMICPOLICY 2021 13The Price of Growth: Consumption Insurance in China 1989-2009 AEJ-MACROECONOMICS 2018 11 Multiple Activities in Networks AEJ-2018 11MICROECONOMICSManagement Quality and Firm Hierarchy in Industry Equilibrium AEJ-MICROECONOMICS 2017 9 Rising Intergenerational Income Persistence in China AEJ-ECONOMIC POLICY2021 8 Socializing at Work: Evidence from a Field Experiment with Manufacturing Workers AEJ-APPLIED ECONOMICS 2019 4 Falling Dominoes: A Theory of Rare Events and Crisis Contagion AEJ-MICROECONOMICS 2016 4 Thy Neighbor's Misfortune: Peer Effect on Consumption AEJ-ECONOMIC POLICY2021 3 Information Acquisition in a War of AttritionAEJ-MICROECONOMICS 2014 3 Credibility of Crime AllegationsAEJ-MICROECONOMICS 2020 2 Trust Building in Credence Goods MarketsAEJ-MICROECONOMICS2022 0 Optimal Nonlinear Pricing by a Dominant Firm under Competition AEJ-MICROECONOMICS 2022 0 Agglomeration, Misallocation, and (the Lack of) Competition AEJ-MACROECONOMICS2021中国台湾学者参与的写作的文章文章名称期刊 年份 被引Parental Education and Child Health: Evidence from a Natural Experiment in Taiwan AEJ-APPLIEDECONOMICS 2010 98Schooling and the Vietnam-Era GI Bill: Evidence from the Draft Lottery AEJ-APPLIEDECONOMICS 2011 72Testing Game Theory in the Field: Swedish LUPI Lottery Games AEJ-MICROECONOMICS2011 44 Confucianism and the East Asian Miracle AEJ-MACROECONOMICS2010 12Understanding Consumption Behavior: Evidence from Consumers' Reaction to Shopping Vouchers AEJ-ECONOMICPOLICY 2017 8Patient Cost-Sharing and HealthcareUtilization in Early Childhood: Evidence from a Regression Discontinuity DesignAEJ-ECONOMICPOLICY2020 5Subsidizing Fuel-Efficient Cars: Evidence from China's Automobile Industry AEJ-ECONOMICPOLICY2021 0其他国家学者参与写作的文章文章名称期刊 年份 被引Why Are Saving Rates of Urban Households in C hina Rising? AEJ-MACROECONOMICS 2010 195Water Pollution Progress at Borders: The Roleof Changes in China's Political Promotion IncentivesAEJ-ECONOMICPOLICY2015 116The Effect of Pollution on WorkerProductivity: Evidence from Call Center Workers in ChinaAEJ-APPLIEDECONOMICS2019 83The Great Housing Boom of ChinaAEJ-MACROECONOMICS2017 76 Demographic Patterns and Household Saving in China AEJ-MACROECONOMICS 2015 42 Health, Height, Height Shrinkage, and SES at Older Ages: Evidence from China AEJ-APPLIED ECONOMICS 2013 40 The Global Welfare Impact of China: Trade Integration and Technological Change AEJ-MACROECONOMICS 2014 37 Sharing High Growth across Generations: Pensions and Demographic Transition in China AEJ-MACROECONOMICS 2015 33 Income Inequality and Progressive Income Taxation in China and India, 1986-2015 AEJ-APPLIED ECONOMICS 2009 30 The Distortionary Effects of Incentives inGovernment: Evidence from China's "DeathCeiling" ProgramAEJ-APPLIEDECONOMICS2017 23 Marriage Networks, Nepotism, and Labor Market Outcomes in China AEJ-APPLIED ECONOMICS 2013 15 The Power of Social Pensions: Evidence from China's New Rural Pension Scheme AEJ-APPLIED ECONOMICS 2021 13 Do College Graduates Serving as Village Officials Help Rural China? AEJ-APPLIED ECONOMICS 2017 13 Aid, China, and Growth: Evidence from a New Global Development Finance Dataset AEJ-ECONOMIC POLICY 2021 13 The Size Distribution of Firms and IndustrialWater Pollution: A Quantitative Analysis ofChinaAEJ-MACROECONOMICS2021 1 Capital Markets in China and Britain, 1770-1860: Evidence from Grain Prices AEJ-APPLIED ECONOMICS 2021 1 Subsidizing Fuel-Efficient Cars: Evidence from China's Automobile Industry AEJ-ECONOMIC POLICY2021 0 Local Protectionism, Market Structure, and Social Welfare: China's Automobile Market AEJ-ECONOMIC POLICY 2021 0 The Marginal Cost of Traffic Congestion andRoad Pricing: Evidence from a NaturalExperiment in BeijingAEJ-ECONOMICPOLICY202011Hometown Ties and the Quality of GovernmentMonitoring: Evidence from Rotation of ChineseAuditorsAEJ-APPLIEDECONOMICS2021 2 Are Chinese Growth and Inflation Too Smooth? Evidence from Engel Curves AEJ-MACROECONOMICS 2016 23 Severe Air Pollution and Labor Productivity: Evidence from Industrial Towns in China AEJ-APPLIED ECONOMICS 2019 74 Income Inequality and Progressive Income Taxation in China and India, 1986-2015 AEJ-APPLIED ECONOMICS 2009 30 The Price of Growth: Consumption Insurance in China 1989-2009 AEJ-MACROECONOMICS 201811一些期刊1.2020年最新按影响因子整理的3483份SSCI 期刊排名！2.2019至今中国高校所有社科类英文期刊发表排名前800强！3.2019-2020中国学者在哪些经济, 商科和管理类期刊发表数量最多？信息量太大了！4.南大新规: 博士生在公众号发文且阅读量超1万，就相当于顶级期刊高水平论文，即可参评国家奖学金！5.中国管理科学(涵盖管理与经济)高质量期刊推荐列表发布！6.AEA下的期刊研究热点, 这一期的主题太前卫, 直言读起来瑟se发dou！7.2020年最新经济,管理, 金融和商业领域SSCI期刊影响因子排名！8.2020年最新按影响因子整理的3483份SSCI期刊排名！9.结果不显著但成功发在Top期刊上的论文有哪些？你心虚过没？10.女性和男性学者分别在哪些期刊发表论文呢？11.2019各社科领域外文Top期刊里各大学(学者)发文情况如何？12.中国台湾省的《经济研究》刊啥水平, 期刊如何分级的？13.重要信号！复旦和上交人文社科学术期刊分级办法，14.找合适的英文期刊发表的神器! 亲测太好用了！15.那些发表过A层次英文期刊的高校经管学院分类，16.经济研究, 管理世界被引用量Top200文章，17.中国英文发表影响力Top60经管学院名单出炉，18.中国内陆学者过去30年发Top5刊的信息都在这里，19.中国哪所高校Top5刊发表数量最多？哪所从未发表过？，20.五大Top经济刊物的在40年里发生了什么？，21.最新研究, 没有T op5刊物, 劝你不要想终身教职!，22.《经济研究》在英文期刊中到底处于什么位置？23.2018年中国学者在SSCI上发文最多的刊物，24.重要信号！复旦和上交人文社科学术期刊分级办法，25.2019中国学者经济各分支一流S刊物发表文章115篇，26.那些发表过A层次英文期刊的高校经管学院分类，27.2019中国学者金融和会计一流S刊物发表文章40篇，28.2019中国学者社会,政治, 公管, 国关一流S刊物发表文章14篇，29.双一流高校在中文经管Top刊物上发表情况，30.清华经济系2010-2018年顶级国际刊物发表情况，31.保密! 高校主办期刊中本校学者所占比例的信息，32.最新按影响因子整理的1-2243名SSCI期刊排名，33.最受人爱戴的经济学期刊, 经济学家调查公布，34.经济学领域英文期刊的审稿情况统计, 审稿周期次数，35.仅仅一天就被Top期刊接受的论文, 太牛了! 36.国际期刊JEL分类号19个分支都有哪些具体子类别? 37.国际顶级期刊最新期动态查看和所有过去刊发文章查看，38.高度关注!《国际期刊预警名单(试行)》发布! 这些期刊都上榜了! 39.C刊的春天可能要来了! 不做科研的博导停止招生, 博士生可以不发论文就毕业！40.包括经管在内所有社会科学的C刊公众号对外公布, 优秀学人及时关注学界动态！41.博士毕业必发C刊论文遭质疑, 供需不平衡，42.C刊代写, 约稿活动猖獗, 买卖市场已成气候，43.中文C刊的审稿信息全统计, 审稿周期次数, 赶快下载关于一些计量方法的合辑，各位学者可以参看如下文章：①“实证研究中用到的200篇文章, 社科学者常备toolkit”、②实证文章写作常用到的50篇名家经验帖, 学者必读系列、③过去10年AER 上关于中国主题的Articles专辑、④AEA公布2017-19年度最受关注的十大研究话题, 给你的选题方向，⑤2020年中文Top期刊重点选题方向, 写论文就写这些。
索罗模型
那么，储蓄率是否越高越好呢？
N(t) c(t) K(t)
+
K ( K(
t t
) )
=
A(t)
K(t)β−1
N(
)t 1−β
=
ρ
+σκ β
.
（7）
根据平衡增长路径定义，K (t) / K (t)是常数，所以方程（7）意味着
N (t)c(t) / K (t)也是常数，令 D = 1 Nc， 求全微分，得：
K
0
=
K K
(t) (t)
设人均消费的增长率 c(t) / c(t) = κ
1）资本价格增长率 （ −σκ ）
由方程（3）得到：
c−σ = θ ⇒ − σ ln c = lnθ θ(t) /θ = −σκ
⇒ θ = −σ c
θ
c
可见，沿着平衡增长路径资本价格增长率为常数。
19
2）资本的边际产出（ ρ + σκ ）
从方程（4）我们得到：
θ = ρ − βA(t)N (t)1−β K (t)β −1 θ
将 θ(t) /θ = −σκ 代入上式，资本的边际产出为：
β A(t)N (t)1−β K (t)β −1 = ρ + σκ
索罗增长理论原文-中文+英文
rigidity in one part of the system should entail lack of flexibility in another. A remarkable characteristic of the Harrod-Domar model is that it consistently studies long-run problems with the usual short-run tools. One usually thinks of the long run as the domain of the neoclassical analysis, the land of the margin. Instead Harrod and Domar talk of the long run in terms of the multiplier, the accelerator, "the" capital coefficient. The bulk of this paper is devoted to a model of long-run growth which accepts all the Harrod-Domar assumptions except that of fixed proportions. Instead I suppose that the single composite commodity is produced by labor and capital under the standard neoclassical conditions. The adaptation of the system to an exogenously given rate of increase of the labor force is worked out in some detail, to see if the Harrod instability appears. The price-wageinterest reactions play an important role in this neoclassical adjustment process, so they are analyzed too. Then some of the other rigid assumptions are relaxed slightly to see what qualitative changes result: neutral technological change is allowed, and an interest-elastic savings schedule. Finally the consequences of certain more "Keynesian" relations and rigidities are briefly considered. II. A MODEL OF LONG-RUN GROWTH There is only one commodity, output as a whole, whose rate of production is designated Y(t). Thus we can speak unambiguously of the community's real income. Part of each instant's output is consumed and the rest is saved and invested. The fraction of output saved is a constant s, so that the rate of saving is sY(t). The community's stock of capital K(t) takes the form of an accumulation of the composite commodity. Net investment is then just the rate of increase of this capital stock dK/dt or K, so we have the basic identity at every instant of time: K = sY. (1) Output is produced with the help of two factors of production, capital and labor, whose rate of input is L(t). Technological possibilities are represented by a production function (2)
更严厉的知识产权保护制度有利于技术创新吗_
（ 2）
就中间品生产部门而言， 假设生产一单位中间品正好耗费一单位最终产品， 则中间品的边际生 产成本等于最终产品的销售价格， 并将之标准化为 1 。 每生产出一种新的中间产品后， 在该中间品 被成功模仿之前可获得持续的正向垄断利润 π ， 由此构建中间品 j 生产商在 v 时刻的决策规划： p j （ v） － 1 ］ · x j （ v） π j （ v） = ［ （ 3） 即中间品设 计 方 案 的 专 利 价 格 V 应 等 于 中 间 品 垄 断 生 产 者 所 获 利 润 π 在 当 期 的 贴 现 值 。 参 考 Furukawa （ 2010 ） ， 引入知识产权保护因素， 得到在 v 时刻垄断生产者所获得的利润流 π （ v ） 的表达式： V（ t） =
厉， 技术被模仿的可能性（ N s = w － 1 ． （ N － N s ） ） 越小， 研发可能获得的垄断利润越多 。 假设单位研发 效率， 即研发成本为 η ， 则在均衡条件下， 研发部门的自由进出条件要求技术创新的研发成本等于新 可以得到利息率的 Bellman 方程： 中间品的净价值， 即 V （ t ） = η 。 结合（ 4 ） 式就该条件对时间求导， （ t） V π r（ t） = + － －1 （ 5） V（ t） V（ t） （ 5 ） 式意味着利息率 r （ t ） 等于研发 投 资 的 回 报 率， 等于研发部门利润率加上研发部门资本价值的 增值（ 或贬值） 率， 减去由于技术被模仿损失的收益率（ ω － 1 ） 。 研发单位成本 η 为常 数 意 味 着 均 衡 （ t ） = 0 。 将（ 2 ） 、 条件下 V （ 3 ） 代入（ 5 ） 式， 整理得到利息率的表达式： r = α1 － α · H · （ 1 － α） · η － 1 － － 1
动态比较优势理论_一种新的模型解释
情况 。③如果满足 :
Ah3 Az3
(t1) (t1)
>
pz∫(t1) ph∫(t1)
>
Ah Az
(t1) (t1)
…………………………… (6)
(相对价格中以上标“ ∫”表示自由贸易状态)
两国在发生贸易后 ,本国的所有劳动力完全被用于生产
z 产品 ,而外国的所有劳动力都完全被用于生产 h 产品 。与
关键词 : 动态比较优势 内生比较优势 产业政策
一 、前言
发展中国家在面对贸易自由化的冲击中 ,往往处于不利 的地位 。一般而言 ,多数发展中国家在低技术产品部门 (资 源密集型 ,劳动密集型) 具有比较优势 ,而在一些高技术部门 (资本密集型 ,技术密集型) 却处于比较劣势地位 。从李嘉图 的比较优势成本学说到现在 ,西方国际贸易理论的发展已经 有了近两百年的时间 。在这个过程中 ,新的理论和新的思想 不断涌现 ,但比较优势的思想始终是理论研究的核心内容 。 同时 ,这个核心思想影响着世界上几乎所有国家对于生产部 门的选择 。按照这个观点 ,一国试图利用任何产业政策进行 干预 ,进行逆向生产 ,都将有损于社会福利的提高 。然而 ,对 于发展中国家而言 ,李嘉图所揭示的只是静态的理论 ,忽略 了时间的因素 ,如果按照这样的分工原则进行生产部门的选 择并不容易为广大发展中国家接受 。主要是因为 ,按照这个 原则进行的国际分工容易使得发展中国家贸易条件逐步恶 化 ,并且在未来的分工体系中处于不利地位 ,延缓了发展中 国家的工业化进程 。发展中国家迫切希望通过自身的工业 化努力实现产业结构的升级 ,也即实现由低技术产业 (主要 指资源密集和劳动密集型产业) 向高技术产业 (主要指资本 和技术密集型产业) 转化 。这就迫切需要从动态的角度重新 考虑贸易分工的问题 ,即动态比较优势理论 。
CFA二级公式表
^
H0 : b 0 ˆ t b , df n k 1 sb
Reject h0 if | t | critical t or p-value <
ˆ (t s ) Confidence Interval: b j c bj
Currency appreciates due to: (1) Lower relative income growth rate. (2) Lower relative inflation rate. (3) Higher domestic real interest rate. (4) Improved investment climate. 9. Unanticipated shift to exp. Monetary Policy: Higher income, accelerated inflation, lower real interest rates, leads to currency dept, current acct surplus, and financial acct deficit. 10. Unanticipated shift to exp. Fiscal Policy: currency appr, current acct deficit, & financial account surplus. 11. Purchasing Power Parity: Law of one price: a single, clearly comparable good should have same real price in all countries. Relative PPP: Countries with high inflation rates should see their currencies depreciate.
伍德里奇计量经济学第六版答案Chapter-15
伍德⾥奇计量经济学第六版答案Chapter-15CHAPTER 15TEACHING NOTESWhen I wrote the first edition, I took the novel approach of introducing instrumental variables as a way of solving the omitted variable (or unobserved heterogeneity) problem. Traditionally, aneous equations models. Occasionally, IV is first seen as a method to solve the measurement error problem. I have even seen texts where the first appearance of IV methods is to obtain a consistent estimator in anAR(1) model with AR(1) serial correlation.The omitted variable problem is conceptually much easier than simultaneity, and stating the conditions needed for an IV to be valid in an omitted variable context is straightforward. Besides, most modern applications of IV have more of an unobserved heterogeneity motivation.A leading example is estimating the return to education when unobserved ability is in the error term. We are not thinking that education and wages are jointly determined; for the vast majority of people, education is completed before we begin collecting information on wages or salaries. Similarly, in studying the effects of attending a certain type of school on student performance, the choice of school is made and then we observe performance on a test. Again, we are primarily concerned with unobserved factors that affect performance and may be correlated with school choice; it is not an issue of simultaneity.The asymptotics underlying the simple IV estimator are no more difficult than for the OLS estimator in the bivariate regression model. Certainly consistency can be derived in class. It is also easy to demonstrate how, even just in terms of inconsistency, IV can be worse than OLS if the IV is not completely exogenous.At a minimum, it is important to always estimate the reduced form equation and test whether the IV is partially correlated with endogenous explanatory variable. The material on multicollinearity and 2SLS estimation is a direct extension of the OLS case. Using equation (15.43), it is easy to explain why multicollinearity is generally more of a problem with 2SLS estimation.Another conceptually straightforward application of IV is to solve the measurement error problem, although, because it requires two measures, it can be hard to implement in practice.Testing for endogeneity and testing any overidentification restrictions is something that should be covered in second semester courses. The tests are fairly easy to motivate and are very easy to implement.While I provide a treatment for time series applications in Section 15.7, I admit to having trouble finding compelling time series applications. These are likely to be found at a less aggregated level, where exogenous IVs have a chance of existing. (See also Chapter 16 for examples.)187SOLUTIONS TO PROBLEMS15.1 (i) It has been fairly well established that socioeconomic status affects student performance. The error term u contains, among other things, family income, which has a positive effect on GPA and is also very likely to be correlated with PC ownership.(ii) Families with higher incomes can afford to buy computers for their children. Therefore, family income certainly satisfies the second requirement for an instrumental variable: it is correlated with the endogenous explanatory variable [see (15.5) with x = PC and z = faminc]. But as we suggested in part (i), faminc has a positive affect on GPA, so the first requirement for a good IV, (15.4), fails for faminc. If we had faminc we would include it as an explanatory variable in the equation; if it is the only important omitted variable correlated with PC, we could then estimate the expanded equation by OLS.(iii) This is a natural experiment that affects whether or not some students own computers. Some students who buy computers when given the grant would not have without the grant. (Students who did not receive the grants might still own computers.) Define a dummy variable, grant, equal to one if the student received a grant, and zero otherwise. Then, if grant was randomly assigned, it is uncorrelated with u. In particular, it is uncorrelated with family income and other socioeconomic factors in u. Further, grant should be correlated with PC: the probability of owning a PC should be significantly higher for student receiving grants. Incidentally, if the university gave grant priority to low-income students, grant would be negatively correlated with u, and IV would be inconsistent.15.2 (i) It seems reasonable to assume that dist and u are uncorrelated because classrooms are not usually assigned withconvenience for particular students in mind.(ii) The variable dist must be partially correlated with atndrte. More precisely, in the reduced formatndrte = 0 + 1priGPA + 2ACT + 3dist + v,we must have 3 0. Given a sample of data we can test H0: 3 = 0 against H1: 3 0 using a t test.(iii) We now need instrumental variables for atndrte and the interaction term,priGPA atndrte. (Even though priGPA is exogenous, atndrte is not, and so priGPA atndrte is generally correlated with u.) Under the exogeneity assumption that E(u|priGPA,ACT,dist) = 0, any function of priGPA, ACT, and dist is uncorrelated with u. In particular, the interaction priGPA dist is uncorrelated with u. If dist is partially correlated with atndrte then priGPA dist is partially correlated with priGPA atndrte. So, we can estimate the equationstndfnl = 0 + 1atndrte + 2priGPA + 3ACT + 4priGPA atndrte + u188by 2SLS using IVs dist, priGPA, ACT, and priGPA dist. It turns out this is not generally optimal. It may be better to add priGPA2 and priGPA ACT to the instrument list. This would give us overidentifying restrictions to test. See Wooldridge (2002, Chapters 5 and 9) for further discussion.15.3 It is easiest to use (15.10) but where we drop. Remember, this is allowed because= and similarly when we replace x with y. So the numerator in the formula for iswhere n1 = is the number of observations with z i = 1, and we have used the fact that /n1 = , the average of the y i over the i with z i = 1. So far, we have shown that thenumerator in is n1(). Next, write as a weighted average of the averages over the two subgroups:= (n0/n) + (n1/n),where n0 = n n1. Therefore,= [(n n1)/n] (n0/n) = (n0/n) ( - ).Therefore, the numerator of can be written as(n0n1/n)().By simply replacing y with x, the denominator in can be expressed as (n0n1/n)(). When we take the ratio of these, the terms involving n0, n1, and n, cancel, leaving= ()/().15.4 (i) The state may set the level of its minimum wage at least partly based on past or expected current economic activity, and this could certainly be part of u t. Then gMIN t and u t are correlated, which causes OLS to be biased and inconsistent. 189。
城乡收入差距与经济增长_基于STR模型的实证分析
将会阻碍经济增长 。 Galor和 Zeria (1993)建立信用市场不完善模型 ,证明了当存在信贷约束时 ,资源的初始 分布对人力资本的积累有着非常重要的作用 。在财富分配非常不平等的情况下 ,由于信贷市场的不完善 ,人 们不可能自由借贷 ,只有少数人才能投资于人力资本 ,从而降低了经济增长 。 Persson和 Tabellini ( 1994)认 为 ,物资资本及人力资本的积累受到一国税收政策的影响 ,如果对富人征收高额税收来降低 (或缩小 )收入 差距 ,那么就会降低人们的生产积极性 , 从而不利于经济增长 。 ( 3 ) 不确定性 。尹恒 、龚六堂和邹恒甫 (2005)运用一个政治经济模型研究在财政支出同时具有生产性和消费性 ,同时进入生产函数和代表性个人 的效用函数时收入分配不平等对经济增长的影响 ,其研究结论表明 ,在经济均衡时 ,经济增长率与税率呈倒 U 型关系 ,经济增长率随着税率的增加先升后降 ;在政治均衡时 ,税率与收入分配不平等呈正相关关系 ,因而 收入分配不平等与经济增长之间存在一定程度的库兹涅兹倒 U 型关系 。M arta Bengoa - Calvo (2004)通过拉 姆齐模型证明了收入不平等与经济增长之间存在着二次型关系 。
t
= 1,
……,
T,
ε t
～N
iid
( 0,σ2
)
(1)
K
∏ G (γ, c, st ) = { 1 + exp [ - γ
( st - ck ) ] } - 1
k =1
γ > 0, K = 1或 2
(2)
其中 , Zt = (W t ′, X t ′) ′为解释变量的矩阵 , W t 为 p + 1阶列向量 , W t ′= ( 1, yt , yt - 1 , …, yt - p ) ′, X t 为 k阶列 向量 , X t ′= ( x1t , x2t , …, xkt ) ′。G为转换函数 (其中 G∈[ 0, 1 ] ) ,其函数值依赖于参数 γ, st , ck ,参数 γ( > 0)为 平滑参数 ,表示为从一个状态 (或区制 )转移到另一个状态 (或区制 )的转换速度或调整的平滑性 ; st 为状态 变量 (转移变量 ) ,转移变量 st 可以为 Zt 向量当中的组成部分 、组成部分的函数或一个不包括在 Zt 内的外生 变量 (如时间变量 t) ;参数 ck 为门限参数 ,可解释为不同状态体制下的门阈值 , 其决定了模型动态变化发生 的位置参数 。向量 <、θ分别表示非线性 STR模型中的线性部分和非线性部分 。向量 Xt 当中可以包括任何 一个稳定的外生变量或确定的变量 。
索洛-斯旺增长模型
比较不同国家或地区的发展水平
通过比较不同国家或地区之间索洛-斯旺模型的参数，可以评估各 国或地区的发展水平和发展阶段。
制定经济发展战略
根据索洛-斯旺模型的结论，政府可以制定针对性的经济发展战略， 优化资源配置，促进经济的持续增长。
引入动态分析，考虑技术进步和资本积累的相互作用；引入制度因素， 分析其对经济增长的影响；考虑非线性生产函数的可能性。
模型的发展方向与未来研究展望
发展方向
将模型与其他经济理论相结合，如内 生增长理论、人力资本理论等，以更 全面地解释经济增长现象。
未来研究展望
探索模型在发展中国家和发达国家的应用， 比较不同国家经济增长的异同；研究全球化 、技术创新等对经济增长的影响；进一步深 化对经济增长机制和动力的理解。
模型的基本假设
假设经济中只存在两种生产要 素：资本和劳动，且资本和劳
动之间可以相互替代。
假设生产函数是规模收益不变 的，即增加投入并不能带来更
大的产出。
假设经济中不存在技术进步和 资本折旧，即经济增长只取决 于资本和劳动的投入。
假设经济中的储蓄率、人口增 长率和技术进步率是外生给定 的，即不受经济系统内部因素 的影响。
06 结论
对索洛-斯旺增长模型的综合评价
01
贡献
索洛-斯旺增长模型为经济增长研究提供了重要的理论基础，它揭示了
资本、劳动和技术进步对经济增长的贡献，并解释了经济增长的源泉。
02
局限性
然而，该模型也存在一些局限性，例如假设条件过于严格，忽略了许多
现实世界中的复杂因素，如经济政策、市场失灵、资源限制等。
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JEconGrowth(2006)11:263–288DOI10.1007/s10887-006-9004-9
ORIGINALARTICLE
Scaleeffectsinendogenousgrowththeory:anerrorofaggregationnotspecification
ChristopherA.Laincz·PietroF.Peretto
Publishedonline:28October2006©SpringerScience+BusinessMedia,LLC2006
AbstractModernSchumpeteriangrowththeoryfocusesontheproductlineasthemainlocusofinnovationandexploitsendogenousproductproliferationtosterilizethescaleeffect.Theempiricalcoreofthistheoryconsistsoftwoclaims:(i)growthdependsonaverageemployment(i.e.,employmentperproductline);(ii)averageemploymentisscaleinvariant.Weshowthatdataonemployment,R&Dpersonnel,andthenumberofestablishmentsintheUSfortheperiod1964–2001providestrongsupportfortheseclaims.WhileemploymentandthetotalnumberofR&Dwork-ersincreasewithnoapparentmatchingchangeinthelong-runtrendofproductivitygrowth,employmentandR&Demploymentperestablishmentexhibitnolong-runtrend.Wealsodocumentthatthenumberofestablishments,employmentandpop-ulationexhibitapositivetrend,whiletheratioemployment/establishmentdoesnot.Finally,weprovideresultsoftimeseriestestsconsistentwiththepredictionsofthesemodels.
KeywordsEndogenousgrowth·R&D·Scaleeffects·Firmsize·EstablishmentsJELCodesE10·L16·O31·O40
C.A.Laincz(B)DepartmentofEconomics,LeBowCollegeofBusiness,DrexelUniversity,32nd&MarketSts.,Philadelphia,PA19104,USA
P.F.PerettoDepartmentofEconomics,DukeUniversity,Durham,NC27710,USA264JEconGrowth(2006)11:263–2881IntroductionThetheoryofendogenousgrowthdevelopedinthepast15yearsputstechnologicalinnovationattheforefrontofexplanationsofdifferencesinstandardsoflivingacrosscountriesandtime.Insodoing,itemphasizesfeaturesoftherealworldlikeimperfectcompetition,accumulationofintangibles,economiesofscale,creativedestruction,andthedistinctionbetweenqualityimprovementsandthecreationofnewproducts,thatgeneratefar-reachingpolicyimplications.Thisconnectionbetweenpolicyandthelong-rungrowthrateconstitutes,inourview,themainattractionofthetheoryandexplainsthevarietyofissuestowhichresearchershaveappliedit;seeforexamplethebreadthoftopicscoveredinGrossmanandHelpman(1991)andAghionandHowitt(1998).Perhapsbecauseitisthemostvisibleconsequenceofincreasingreturns,testsofthetheorytendtofocusonthe“scaleeffect”predictionofthemodelsproposedbyRomer(1990),GrossmanandHelpman(1991),andAghionandHowitt(1992).ThestrongestformulationofthecritiqueisduetoJones(1995b).Thescaleeffectsaysthatanincreaseinthelaborendowmentofaneconomyleadstoahighergrowthrateofproductivity.JonespointsoutthatthispredictionstemsfromtheassumptionthatthegrowthrateofproductivityisproportionaltothenumberofscientistsandengineersengagedinR&D.Hethendocumentsthatthisassumptionisinconsistentwiththetime-seriesdataonR&DinputsandoutputsfortheUS.Mostresearchers—includingus—accepthisconclusionthatthisevidencepointstoaproblem.Thereisdisagreement,however,concerningthesolution.Twoapproacheshaveemerged.Onepositsdecreasingreturnstoknowledgeinordertoavoidthescaleeffect.Theproposedmodelfeatures“semi-endogenous”growthinthesensethatthesteady-statelevelofproductivityisendogenousandsub-jecttopolicyaction,whileitsgrowthrateisproportionaltothegrowthrate(asopposedtothelevel)ofR&Dinputswhich,inequilibrium,ispinneddownbythe(exogenous)populationgrowthrate.Thisalterationofthetheoryfaresnobetterwhenconfrontedwiththeempiricalevidence(Aghion&Howitt,1998,2005;Ha&Howitt,2006).Thesecondapproachmakesasubstantialdeparturefromtheoriginalformulationofthetheory.TheearlymodelspositR&DtechnologiesthatfeatureproportionalityofproductivitygrowthtoaggregateR&Dinputs.Incontrast,themodelsdevelopedbyPeretto(1996,1998,1999),Dinopoulos&Thompson(1998),Young(1998),Howitt(1999)andPeretto&Smulders(2002)shiftthefocusfromthewholeeconomytotheindividualproductlineasthemainlocusofinnovation.Insuchadisaggregatedframe-workitisstraightforwardtodisposeofthescaleeffect.Aprocessofdevelopmentofnewproductlinesfragmentstheeconomyintosubmarketswhosesizedoesnotincreasewithpopulation.Thisprocesssterilizestheeffectofthesizeoftheeconomyonfirms’incentivestodoR&D.Thecrucialfeaturesofthisversionofendogenousgrowththeoryarethat(i)growthdependsonaverageR&Demployment(i.e.,R&Demploymentperproductline)and(ii)averageR&Demploymentisscaleinvariant.Feature(i)isaconsequenceoftheassumptionthatinnovationhappensatthefirm(productline)level,notattheeconomylevel,whilefeature(ii)isaconsequenceofendogenousproductproliferationdrivenbyeconomicincentives.Thesemodelsemphasizethefollowingmechanism.Anincreaseintheaggregatelevelofemploymentallowsexistingfirmstoincreasetheirsize,butitsimultaneouslyinducesentryofnewfirmsthatdrawslaborawayfromincumbents.Asaresult,inthelongrunaveragefirmsizeisinvarianttothescaleoftheeconomy.Theconsequenceofthisprocessofmarketfragmentationisthatfundamentalsandpolicyvariables