Extensive and Intensive Growth

本项目旨在扩展增长理论和发展经济学的最新创新，以解释不同国家和不同时期的不同增长模式。最近的研究已经解决了这一问题，但已经出现的最重要的模型，如Lucas、Romer或Boyd-Prescott的模型，倾向于预测具有相似初始条件的经济体的类似行为。他们无法解释这样一个事实，即在某些时间点看起来相对相似的许多国家（比如1940年左右的加拿大和阿根廷）在后来的经济时期看起来非常不同。在他们自己之前的工作中，主要研究人员已经给出了一些例子，说明如何发展理论来解释为什么具有相似“初始条件”的经济体的人均产出遵循非常不同的时间路径。在这项建议中，他们试图扩展他们早期的工作，以便将内生人口动态理论与人均收入决定理论结合起来。现有的增长模式表明，人口和（人均）收入的动态应该相互作用。该建议提出了几个模型，这些模型进行了这一富有成果的研究。更具体地说，研究人员建议详细阐述一个内生人口增长的动态理论，该理论与公认的历史发展模式相一致，并有助于确定一些不太明显的原因，为什么有些国家在很长一段时间内比其他国家增长得更快。他们试图阐明的规律包括：(1)过去四百年来欧洲和亚洲许多地区人口增长的逻辑模式；许多成功的发展中国家从早期的广泛经济增长时期过渡到后来的密集经济增长时期；周期约为16年的生育周期；第四，最慢的增长往往发生在最贫穷的国家。其基本理论不同于现有关于内生生育率的文献，因为传统经济中的儿童主要是作为生产要素而不是作为消费品来建模的。贸易条件允许通过家庭内部谈判而不是竞争市场来确定。新模型设计得很好，可以回答一系列丰富的问题，但仍然易于分析。它们不仅从增长理论和发展经济学的角度具有挑战性，而且具有高度的政策相关性。尽管到目前为止，其他研究人员在关键问题上进展甚微，但研究人员的工作已经取得了足够的进展，有望取得各种重大成果。

This project seeks to expand on recent innovations in growth theory and development economics in order to explain different patterns of growth in different countries and time periods. Recent work has addressed this topic but the most important models which have emerged, such as those of Lucas, Romer, or Boyd-Prescott, tend to predict similar behavior for economies with similar initial conditions. They are unable to account for the fact that a variety of countries that look relatively similar at certain points in time (say Canada and Argentina around 1940) look very different economically at later dates. In their own previous work, the principal investigators have given examples of how theories can be developed to explain why economies with similar "initial conditions" follow very different time paths for per capita output. In this proposal they seek to extend their earlier work in order to integrate a theory of endogenous population dynamics with a theory of per capita income determination. Existing growth models suggest that population and (per capita) income dynamics should interact. This proposal sets forth several models that carry on this fruitful line of research. More specifically, the investigators propose to elaborate a dynamical theory of endogenous population growth that is consistent with well-established historical development patterns and helpful in identifying some of the less obvious reasons why some countries grow faster than others over long periods of time. Among the regularities they seek to illuminate are (i) a logistic pattern of population growth in many parts of Europe and Asia over the last four hundred years; (ii) the passage of many successfully developing countries from an early extensive period of economic growth to a later intensive period; (iii) fertility cycles with a period of approximately sixteen years; and (iv) the slowest growth often occurs in the poorest countries. The underlying theory differs from existing literature on endogenous fertility in that children in traditional economies are modelled primarily as factors of production rather than as consumption goods, and the terms of trade are allowed to be set by intra- family bargaining instead of competitive markets. The new models are well designed to answer a rich set of questions, but are still tractable to analyze. Not only are they challenging from the standpoint of growth theory and development economics, but they are also highly policy-relevant. Although other researchers have made little progress on the key issues to date, the work of the investigators is far enough advanced to give promise of a variety of significant results.