收入不确定与生育意愿 ——基于阶层流动的调节效应

本文基于中国综合社会调查（CGSS）数据,采用Logit回归模型检验了收入不确定、阶层流动与生育意愿的关系。结果显示：收入不确定显著抑制了二孩生育意愿;与高收入阶层相比,低收入家庭脆弱性更大,收入不确定显著抑制其生育意愿;暂时性收入波动对男性二孩生育意愿的抑制作用更明显,但并未降低女性二孩生育意愿;失业率显著降低了女性二孩生育意愿,却并未降低男性二孩生育意愿;社会阶层流动增加了二孩生育意愿,并显著降低了收入不确定对二孩生育的不利影响。     

The Optimal Level of Debt in an OLG Model with Endogenous Fertility

Abstract. In the present work we extend Diamond's OLG model by allowing for endogenous fertility and look at the consequences of such an extension on the rules for optimal public debt issuing. In particular, we show that the condition according to which the rate of growth of population should be higher than the interest rate is no longer sufficient for obtaining welfare improvements via debt increases and that the level of optimal debt is, ceteris paribus, lower than the one arising with exogenous fertility. Finally, a sensitivity analysis shows that the optimal level of debt is higher the lower the capital share, the higher individuals' degree of patience, the bigger the child‐rearing cost and the lower the preference for children. On policy grounds we argue that debt‐tightening policies may be optimal in the long run provided that the cost of rearing children does not increase (or, if anything, does decrease).     

Teenage pregnancies and births in Germany: patterns and developments

We study the development of teenage fertility in East and West Germany using data from the German Socioeconomic Panel and from the German Mikrozensus. Following the international literature we derive hypotheses on the patterns of teenage fertility and test whether they are relevant to the German case. We find that teenage fertility is associated with teenage age and education, with the income of the teenager’s family, with migration status, residence in East Germany and aggregate unemployment. Our evidence supports counter-cyclical teenage fertility.     

中国低生育水平与意愿生育水平的差距

以历次全国性有关生育率的各项调查数据为基础,介绍了中国当前的低生育水平和低生育动态模式。依据近几年全国性有关生育意愿的调查数据,计算了在有计划生育政策条件下和无计划生育政策条件下的中国育龄妇女的意愿生育率。在有和无计划生育政策条件下,中国育龄妇女的意愿生育水平均低于更替水平,生育意愿在一定的相对较短的时期内可以保持稳定。使用官方公布的总和生育率与计算的育龄妇女的总和意愿生育率数据绘制了低生育水平和意愿生育水平之间的差距图。在低生育时代下中国育龄妇女的生育意愿和生育行为存在差距的现象与世界普遍存在的现象是相一致的。     

民族地区人口与生态经济发展初探－－吉林延边朝鲜族与新疆维吾尔族民族比较

计划生育是我国长期的基本国策，通过对我国人口生育水平的时空分析，提出：稳定低生育水平的工作难点关键是少数民族地区。并以吉林延边朝鲜族和新疆维吾尔族生育水平比较研究，结论是：对少数民族的计划生育优惠政策实际是是“好心照顾他，反例害了他”，只有降低生育率才更有利于少数民族地区的生态经济发展。     

Life expectancy and economic development: Evidence from microdata

This study examines the effect of life expectancy on fertility, education, and labor force participation. Using birth and sibling histories from the Demographic Health Surveys conducted in sub‐Saharan Africa, I construct a time series of age‐specific birth rates and mortality rates at the country‐region level. I use these data to test the implications of a general equilibrium model linking life expectancy to fertility, human capital, and labor supply. My results suggest that increases in life expectancy reduce fertility, increase education, and increase labor force participation. Overall, my empirical results suggest that in sub‐Saharan Africa, increases in life expectancy will have a positive impact on growth through fertility, education, and labor supply but that the effect will be small. My results also rule out the possibility that recent shocks to adult mortality in high HIV prevalence countries will reduce fertility, increase labor productivity, and lead to faster growth.     

The Transition to Market Economies in an Endogenous Growth Model with Altruistic Agents

This paper considers an endogenous transition from a self-sufficient traditional economy to a market economy and its consequences on fertility and growth. The transition can occur if private intergenerational transfers are unable to secure old-age consumption as adequately as savings on capital markets; otherwise individuals stay in the traditional economy unless the mass-production technology in the market economy is sufficiently more advanced than individually accessible technologies. Markets emerge only if per capita output exceeds a certain level given a fixed cost of forming markets. The transition reduces fertility and promotes growth under plausible restrictions.
JEL Classification : E 20; J 13; O 10     

Economic analysis of different options in integrated pest and soil fertility management in maize systems of Western Kenya

The major biotic constraints to the production of maize, the major staple food in Western Kenya, are field pests such as Striga and stem borers, and low soil fertility. To counter these constraints, new cropping systems have been developed, including “push‐pull,” rotations with promiscuous soybean varieties and green manure crops, and imidazolinone resistant‐ (IR‐) maize. To analyze the technical and economic performance of these technologies, both with and without fertilizer, on‐farm researcher‐managed long‐term trials were implemented over six seasons in two sites each in Vihiga and Siaya districts of Western Kenya. The economic results, based on marginal analysis using a multioutput, multiperiod model, show that the new cropping systems with fodder intercropping (push‐pull) or soybean rotations were highly profitable. Push‐pull is more profitable but requires a relatively high initial investment cost. Green manure rotation, IR‐maize, and fertilizer all increased yields, but these investments were generally not justified by their increased revenue. We argue that research on rotation and cropping systems to tackle pest and soil fertility problems in Africa deserve more attention. This will require increased collaboration between agronomists and economists to set up long‐term experiments with new cropping systems to develop proper economic models.     

Ecosystem services and dis-services to agriculture

Agricultural ecosystems are actively managed by humans to optimize the provision of food, fiber, and fuel. These ecosystem services from agriculture, classified as provisioning services by the recent Millennium Ecosystem Assessment, depend in turn upon a web of supporting and regulating services as inputs to production (e.g., soil fertility and pollination). Agriculture also receives ecosystem dis-services that reduce productivity or increase production costs (e.g., herbivory and competition for water and nutrients by undesired species). The flows of these services and dis-services directly depend on how agricultural ecosystems are managed and upon the diversity, composition, and functioning of remaining natural ecosystems in the landscape. Managing agricultural landscapes to provide sufficient supporting and regulating ecosystem services and fewer dis-services will require research that is policy-relevant, multidisciplinary and collaborative. This paper focuses on how ecosystem services contribute to agricultural productivity and how ecosystem dis-services detract from it. We first describe the major services and dis-services as well as their key mediators. We then explore the importance of scale and economic externalities for the management of ecosystem service provision to agriculture. Finally, we discuss outstanding issues in regard to improving the management of ecosystem services and dis-services to agriculture.     

关于进一步完善生育政策的若干认识问题

生育政策调整是目前敏感而备受关注的热点问题之一。对坚持现行生育政策不变的理由进行了系统的梳理,逐条分析了这些理由的充分性与合理性。源于生育政策调整的生育率反弹、在生育率水平未明了之前不应进行生育政策调整等都不能成为维持生育政策不变的充分理由。即将来临的第四次出生高峰是人们“臆构”出来的,实际上它根本就不存在。就在生育政策调整问题上全国各地是否应该齐步走以及究竟应该吸取哪些“开小口”的教训等展开了讨论。就人口发展中的欧洲现实、日本经验与韩国教训进行了考察分析。