中国农村人口迁移模型探索——一个对"民工荒"现象新的解释

本文构造了一个理论模型,得出了人口流动均衡条件,从而对“民工荒”现象做出了新的解释。本文的结论是迁移成本和就业概率决定了迁移人口的规模;农村工业部门的发展不仅分担城市就业压力,还缩小农民流动规模;农产品价格波动表示的农业剩余波动使得劳动力无限供给神话提前破灭,但并不意味着二元经济的终结。     

Migration and its Determinants: A Study of Two Communities in Colombia

Using data gathered by the author in two communities in Southwestern Colombia, this paper tests a model of migration which incorporates relative deprivation as one of many possible reasons to migrate. The study finds that the product of relative deprivation and family income not only has a sensible interpretation; it is a better predictor of migration than its two component variables alone. Results also show that families with the highest propensities to migrate are those with the most to gain in terms of being better able to reduce relative deprivation through successful migration. These families, however, are neither at the bottom nor at the top of the income distribution in their communities. The study also finds that those most likely to migrate to the USA conform most closely to the immigration policies of the USA.

The roles of land tenure reforms and land markets in the context of population growth and land use intensification in Africa

This article reviews the past and potential future roles of land tenure reforms and land markets in Sub-Saharan Africa (SSA) as responses to population growth in the process of land use intensification and livelihood transformation. The farm size distribution and the existence of an inverse relationship (IR) between farm size and land productivity in SSA and the implications of this relationship for efficiency and equity are investigated. More secure property rights and removal of restrictions on land markets have the potential to create both efficiency and equity benefits, but there are high risks of elite capture of large land areas with inefficient and inequitable outcomes. This situation is the case not only in land-abundant areas but also in urban and peri-urban areas where increasingly larger proportions of people will make their living. Increasing population pressure in densely populated rural areas contributes to more rapid rural–urban migration, and creating alternative livelihood opportunities for the migrating youth population is essential to achieving economic development with social stability.     

BEYOND THE STARS

It is frequent to hear in economic seminars or read in academic papers that an effect is economically significant or economically important. Yet, the economic literature is vague on what economic importance means and how it should be measured. In this paper, I show that existing measures of economic importance are flawed and misused. I derive a new metric that measures, in percentage terms, the contribution of each explanatory variable to deviations in the dependent variable, ceteris paribus. As an illustration, the method is applied to study the determinants of migration and the determinants of fertility.     

The American frontier: Technology versus immigration

How important was international immigration for the US and its demography during the nineteenth century? This paper investigates, quantitatively, its effect on the westward movement of population and the regional and secular changes in fertility. Beside immigration, two alternative forces are considered: technological progress and the land policy (the Homestead Act). An optimal growth model with endogenous fertility and migration is calibrated, and counterfactual experiments reveal that the main driving forces were productivity growth and the declining cost of transportation. International immigration played a lesser role.     

Remittances as a social status signaling device

Like all human beings, migrants may have a concern about their prestige or social status in the eyes of left-home family and friends. They can remit money in order to signal their economic success and increase their status. We show that if migrants’ income is private information, unsuccessful migrants might accept a worsening of their living conditions and send back home large amounts of remittances only in order to make residents believe that they are successful. In some cases, successful migrants can signal their true favorable economic situation by remitting an even larger amount. The game presents various equilibria that differ with respect to the proportion and nature of the migrants who sacrifice consumption opportunities to status revealing actions.     

Boom, bust, and the poor: Poverty dynamics in the Middle East and North Africa, 1970–1999

This paper analyzes changes in poverty and inequality in the Middle East and North Africa. It finds that the structural relationship between poverty reduction, income growth and distribution is the same for MENA and other developing economies. Prior to 1985 rapid growth sharply reduced poverty. After 1985, despite very low income growth, a rising share of income accruing to the lowest quintile meant that the average income of the poor rose more rapidly than that of the non-poor. These unusual poverty dynamics were primarily due to international migration. Remittances both increased per capita incomes in labor exporting countries and increased the share of income accruing to the poor.     

内生农业技术进步的二元经济增长模型——对“东亚奇迹”和中国经济的再解释

通过吸收内生增长理论的思想 ,修正外生农业技术进步的假设 ,本文提出了一个内生农业技术进步的二元经济增长模型 ,并以此对倍受瞩目也颇多争议的“东亚奇迹”及中国经济 ,从二元经济结构转换的角度进行了分析。本文认为 ,“东亚奇迹”是传统农业劳动力不断转向现代非农业部门的结果 ;是现代部门以资本反哺传统部门 ,推动农业技术进步 ,促进劳动力转移的结果 ;也是现代部门均衡发展 ,吸纳剩余劳动力 ,加速结构转换的结果。因此 ,虽然非农部门的全要素生产率提高不够显著 ,但劳动力结构转换仍然推动经济实现了持久的高速增长。     

A tale of two countries: Directed technical change,trade and migratory movements

We propose a North-South model that reconciles trade and production strategies, flows of innovators and the path of economic divergence, or convergence, between countries. We explain the mechanisms behind these forces and show how the technological and economic gaps can be reversed if southern countries stop imitating northern goods and, instead, produce complementary goods. Such a strategy of complementarity on production yields the necessary incentives to innovators to engage in research in southern countries, which enhances the catching-up process between countries. It is also shown that migratory movements of unskilled labor between countries are also relevant to understand the dangers and benefits of different trade strategies for economic growth. This paper suggests a positive (negative) correlation between technological innovation in the North (South) and the level of substitutability in production, while under complementarity, technological innovation catches up in the South, therefore fostering the economic catching up process. A positive correlation between inflows of skilled and unskilled labor and substitutability of production between countries is also verified.     

城镇化视角下的农村人力资本投资研究

本文在分析农村人力资本投资对城镇化的重要作用的基础上,指出了当前农村人力资本投资中存在的影响城镇化发展的种种不足.最后,在城镇化的视角下,提出了改善农村人力资本投资的建议.