中国妇女生育水平变动考证和未来人口发展的策略选择

1990年以来各类人口调查和相关学者的研究结果显示,目前的低生育水平的实现有外在政策强力的作用,更有中国社会经济发展内生化的作用;真实的生育水平既不是调查包括人口普查所显示的那样低(低于1.5),也不是有关部门和政府所想象的那样高。调查显示农村居民平均生育意愿不会高于2个孩子,这是生育率持续稳定的根本。众所周知,为了保证人口稳定持续的发展,应使妇女生育率保持更替水平或至少接近更替水平。从人口发展规律和人口发展与社会经济发展相适应的规律出发,结合当前我国居民生育意愿和生育水平走低的实际,我们应该抓住生育政策调整的最佳时期,调整应该在最佳时期即未来5-10年内完成。     

21世纪中国人口面临的艰难抉择──生育率与人口规模·老龄化的前瞻

总人口、老年人口规模与生育率呈正向变化以及老龄化程度与生育率呈反向变化的矛盾, 决定了低生育率导致人口数量较少但高度老龄化; 高生育率导致人口规模扩大但老龄化程度较低,造成未来生育政策调整的艰难抉择。促进人口与社会经济、资源环境的协调发展和可持续发展是未来中国发展的最主要矛盾,继续坚持低生育率政策,坚持严格控制人口数量是首要任务     

生育率演变的生态学逻辑及人口增长的长期趋势

人口增长的长期过程一直是充满困惑与引发争论的话题,将人类复归到生态系统的普通成员,按照生态学逻辑构建一个由替代生育率内生引导、人口容量外生制约的人口增长新模型,以代替用具体社会经济因子解释短周期人口变动的传统思路,探讨生育率转变的一般模式及人口发展的长期趋势。工业革命以来,全球人口已经或正在经历着第一次、第二次生育率转变,全球生育率演变可以聚类为欧美、亚非拉、撒哈拉以南非洲和东亚四种区域模式;在计划生育政策的推动下,我国在短短的三十年内完整经历了两次生育率转变。极限替代生育率是生育率演变的长期目标,但当前已有一些国家跌破更替水平,这也许会成为各个国家的普遍经历,预示着人口容量约束的日益显性化;世界及主要国家的人口规模正在日益逼近其容量极限,并会在惯性驱动下突破容量限制,达到峰值后再以负增长方式趋近人口容量,同期的生育率也将向极限替代生育率递增复归。按趋势模拟世界和中国的可持续人口容量分别约为65亿人和12亿人。研究设计出测量人口增长惯性的新指标——人口增长惯性系数,它是生育率与实时替代生育率之比或出生率与死亡率之比,相比常用的人口惯性因子更为简便易行。     

The Long-Term Effect of the Timing of Fertility Decline on Population Size

Existing long-range population projections imply that the timing of the fertility transition has a relatively unimportant effect on long-term population size when compared with the impact of the level at which fertility is assumed eventually to stabilize. However, this note shows that the effect of the timing of fertility decline is a function of the eventual fertility rate: the lower the eventual fertility rate, the greater the effect of the timing of the transition becomes. This finding has important implications for projection methodology, as well as for policies related to the consequences of long-term levels of population size.     

我国流动人口生育问题研究概述

在我国经济社会的高速发展影响下,流动人口数量与日俱增。流动人口中的育龄人群也在我国整体育龄人群中占较大比例．因此其生育问题受到了广泛关注。当前学界对流动人口的生育问题主要围绕其生育意愿、生育水平、生育服务管理而展开,通过研究发现流动人口的生育状况由于其居住、工作等的特殊性而呈现出一些不同于城市常住人口和农村未流动人口等的特点。而要将研究进一步引向深入,扩展地域之维、丰富实地调研资料、探析数理关系是可尝试的分析路径。     

Shifting shares of the population and U.S. fertility

American fertility, as measured by the total fertility rate, apparently has been climbing since 1988 and could approach replacement level in 1990. Three possible explanations are explored: incorrect denominators, actual fertility increase, and changing ethnic proportions of the population. Using California data as a surrogate for the nation, it is found that at least part of the gain in fertility is attributable to what is called "shifting shares." Given that minorities have higher fertility than the majority, as these groups increase their share of the population, the nation's fertility can be expected to continue climbing. Any attempt to attain zero population growth must therefore be postponed indefinitely.     

中国人口生育变化及影响因素——基于第六次人口普查的分析

本文在"六普"汇总数据的基础上,定量分析中国人口的生育水平、生育模式的变化和生育变化的影响因素。研究发现,在生育水平持续下降的情况下,结构性因素逐渐成为左右未来中国生育水平走向的决定性因素;生育模式正在向初婚初育间隔扩大,生育孩次向低孩次集中的方向发展;尽管年龄别已婚生育率的变化使得中国一般生育率上升9.613%,在导致生育水平下降的各因素中,育龄妇女年龄结构、婚姻状态等人口因素的影响显得越来越重要。研究结果对于正确理解我国的人口形势,科学地规划和调整人口政策具有十分重要的意义。     

Indigenous fertility in the Northern Territory of Australia: what do we know? (and what can we know?)

In the Northern Territory of Australia, Indigenous people make up 30% of the population. Demographic features of the Indigenous population are thus important for understanding Northern Territory population dynamics, but our understanding of what is happening within the Indigenous population is limited by poor data and limited research attention. This paper exploits birth registration and census data to explore Northern Territory Indigenous fertility trends over a 20-year period. It investigates whether fertility decline identified for the 1960 and 1970s is a contemporary feature of Indigenous fertility in the Northern Territory. Results show that our understanding of Northern Territory Indigenous fertility is heavily constrained by data and that trend analysis is essential for avoiding erroneous conclusions because of annual fluctuations. The outstanding feature of Indigenous fertility in the Northern Territory is women becoming mothers at extremely early ages, particularly in rural and remote parts of the Territory. Age patterns appear to have changed little since the middle of last century despite modest declines in age-specific fertility at the youngest ages. While these declines may continue, any trends will be slow to emerge. Continued close scrutiny of data sources and monitoring of trends is needed to ensure that Northern Territory population dynamics are properly understood, and care must be taken in interpreting results to make certain policy interventions aimed at population outcomes are appropriate and achievable.     

Immigrants’ ages and the structure of stationary populations with below-replacement fertility

A sustained regime of low fertility plus immigration yields an unusual kind of stationary population. The author demonstrates that all stationary populations have a common structure, and that the familiar replacement-level fertility population is the youngest among the many stationary populations corresponding to a particular life table. This finding has important consequences for policy because although fertility increase and immigration are equally effective at halting population decline, immigration is inferior as a means of rejuvenating low-fertility populations. In fact, an immigration-based policy could make a low-fertility population older rather than younger. The paper includes examples using U.S. and West German vital rates.     

Population dynamics in Germany: the role of immigration and population momentum

The effects of changes in rates of mortality, fertility, and migration depend not only on the age-specific patterns and levels of these rates, but on the age structure of the population. In order to remove the influences of the age structure and concentrate on the effects of the demographic rates themselves, a common practice is to analyze the influences of the rates for a standard age structure. This paper analyzes current and future population changes in Germany, using a stationary population equivalent model (SPE) that shows long-term effects of current fertility, mortality, and international migration patterns. Results indicate that the German population will eventually decline because of below replacement fertility, if net immigration does not counteract this decrease. This means, for instance, that the long-term stationary population levels for Germany will decrease by approximately 6.5 million during a decade in which current fertility, mortality, and international migration levels prevail. The paper also reports how various other assumptions for mortality, fertility, and international migration affect the SPE model for Germany.     

A new method for estimating the level of natural fertility in populations practicing birth control

The natural fertility schedule of a population is the schedule of age-specific marital fertility we would observe if no birth control were being practiced. In natural fertility (no birth control) populations we can observe the natural fertility schedule directly, but in populations practicing birth control the natural fertility schedule is disguised by the marital fertility rates in those age intervals in which control is exercised, the marital fertility rates being below the natural rates. This paper elaborates a method for estimating the natural fertility schedules of populations practicing birth control. Two alternative models are presented, one nonlinear and one linear. The use of these models is then illustrated with reference to the Old Order Amish population of Lancaster County, Pennsylvania. It is shown that for Amish women born between 1860 and 1900 both the nonlinear and linear models yield an estimate of .843 as the ratio between Amish and Hutterite natural fertility schedules.     

曲折、艰难、辉煌的中国生育转变

从1979～2009年30年人口变动的历程来看,中国人口转变是成功的,其结果是辉煌的,但其转变的历程,尤其是生育转变的历程是曲折和艰难的,历史留给人们的经验和教训是深刻的。本文将近30年来的生育转变历程为四个阶段,从而突显了不同阶段生育水平的变化,以及生育水平与社会经济变革、生育行为以及生育政策博弈的结果。1979～1984年生育水平反弹波动,反映出严格的生育政策遇到强大阻力,结果是欲速而不达。1985～1991年生育高峰如期而至,显示了人口内在规律的强大威力,从而最大限度地调动了人口控制的力量。1992～1999生育率再次下降,并穿透替代水平生育率,宣告人口转变基本完成。2000～2009低生育水平持续稳定,人口结构性问题逐步显现,统筹解决人口问题势在必行。     

Fertility Transition in China:A Zigzag and Splendid Course

Examining China’s population changes in the past three decades demonstrates that China’s demographic transition has been successfully completed with a splendid and zigzag path.There are profound historical experiences and lessons.This paper reviews China’s fertility transition which is divided into four periods and argues that fertility changes are a result of the interactions between socioeconomic development,fertility behaviors and fertility policies.Substantial resistance to the "one-childpolicy" during 1979 to 1984 resulted in rebounding and fluctuating fertility.The baby boom occurred in the period 1985 to 1991 was a manifestation of the inherent laws of demographic dynamics,and subsequently forceful birth control was again mobilized.The period from 1992 to 1999 witnessed large declines in fertility which penetrates the replacement zone,showing that China was completing the fertility transition.China’s stabilizing low fertility and emerging population structural issues since 2000 call for comprehensive ways in addressing the population problems.     

Empirical analysis of the contribution of age composition to population growth

The method of decomposition is applied to rates of natural increase in order to elucidate the role played by age composition in the growth of populations. A population’s age distribution and fertility schedule are contrasted to those in a "stationary" population having the same mortality rates and having a fertility schedule equal to that of the observed population divided by its net reproduction rate. In this manner it is shown that about one-quarter to one-third of the growth of most current high-growth populations can be attributed to non-stationarity of their age distributions. This fraction will rise, as it has in most industrialized countries, if fertility is reduced and age distributions become middle-heavy. In projections of the 1963 Venezuelan female population with fertility rates declining by 20/0 and 1% annually, more than half of the growth (in numbers) that occurs prior to zero-growth attainment is contributed by non-stationarity of its intervening age distributions.

     

Immigration and the stable population model

This paper reports on work aimed at extending stable population theory to include immigration. Its central finding is that, as long as fertility is below replacement, a constant number and age distribution of immigrants (with fixed fertility and mortality schedules) lead to a stationary population. Neither the level of the net reproduction rate nor the size of the annual immigration affects this conclusion; a stationary population eventually emerges. How this stationary population is created is studied, as is the generational distribution of the constant annual stream of births and of the total population. It is also shown that immigrants and their early descendants may have fertility well above replacement (as long as later generations adopt and maintain fertility below replacement), and the outcome will still be a long-run stationary population.     

Study on Standard of Population Aging

Do an increase in ageing in developed countries and"getting old before getting rich"in developing countries indicate that f luctuations in the population age structure have produced a qualitative change?What is a qualitative change and what is a quantitative change?Here we propose a new concept of Shadow Population,then establish a new standard for evaluating population age structure,finally present a typical five stage population age structure type transition model.The model simulation shows that all world regions are still in the adult stage and that population ageing belongs to the category of quantitative change.However,sustained low fertility will lead to a qualitative change in the ageing population.The current pressure of population aging in the adult stage placed on the pension security system shows that this system is truly not a sustainable system,Gradually raising the retirement age and Long-term stability in replacement fertility is the key to solving the socioeconomic development dilemma presented by future population ageing in low fertility regions or countries,but the latter is more urgent.     

Population growth with variable family size

"The Sharpe-Lotka continuous time deterministic model of population growth is developed to take account of some possible forms of mother-daughter fertility association....Model specific results relating the intergenerational fertility effect to the long term population growth rate and magnitude are established. The quantitative implications of the theory are illustrated by a consideration of a general bilinear form of A and in this context numerical results illustrating the finite time growth and also the long term distribution of fertility levels in the stable female population are obtained. In particular, it is shown that different fertility specific subpopulations can coexist indefinitely."     

2000年以来中国城乡生育水平的比较分析

我国城乡生育水平、发展趋势及差异程度的对比研究对于人口发展问题意义重大。首先通过运算,得出了城乡总和生育率指标数值,呈现出2000年以来十年间城乡生育状况,然后对这些数据进行了细致的比较与分析。研究结果表明：尽管十年中生育水平呈现波动状态,但农村总和生育率一直都低于1．8,城镇则低于1．3,差异近几年有逐步缩小的趋势;城乡生育水平差异主要来自二孩生育率的差异,二孩生育率近十年来有微弱上升趋势;一孩生育率受民俗等因素影响较大,城镇波动大于农村;平均生育年龄推迟现象在城镇、农村一直都在缓慢持续。     

The effect of variability in the fertility schedule on numbers of kin

"The kinship formulas developed by Goodman, Keyfitz, and Pullum (1974) are extended to encompass populations in which fertility varies among women. An expression is derived to determine the amount by which the number of sisters in a heterogeneous population exceeds that in a population with homogeneous fertility. This expression, which is a function of the variance in the gross reproduction rate of the population, can readily be applied to numbers of other kin, such as aunts and cousins. Several trial calculations indicate that calculations of average numbers of sisters based on an assumption of uniform fertility could result in a underestimate of about 13 percent." (SUMMARY IN FRE)     

从稳定人口与人口再生产认识总和生育率真实涵义

文章阐述了总和生育率的来源、内涵及其理论基础,论述了人口粗、净再生产率表征更替生育水平与用总和生育率来表征更替生育水平的差异与不同;阐述了稳定与非稳定人口的差异和稳定人口理论的不足之处。文章指出,总和生育率属于稳定人口的指标,在度量非稳定人口的生育水平时,总和生育率是一个假定性条件极强的指标,必然要与实际非稳定人口生育水平存在差异。因此正确认识以总和生育率的真实涵义颇具现实意义。