Migration, fertility, and aging in stable populations

Fertility is below replacement level in all European countries, and population growth is expected to decline in the coming decades. Increasing life expectancy will accentuate concomitant aging of the population. Migration has been seen as a possible means to decelerate aging. In this article, I introduce a stable, open-population model in which cohort net migration is proportional to births. In this case, the migration-fertility trade-off can be studied with particular ease. I show that although migration can increase the growth rate, which tends to make the age distribution younger, it also has an opposite effect because of its typical age pattern. I capture the effect of the age pattern of net migration in a migration-survivor function. The effect of net migration on growth is quantified with data from 17 European countries. I show that some countries already have a level of migration that will lead to stationarity. For other countries with asymptotically declining population, migration still provides opportunities for slowing down aging of the population as a whole.     

中国老年人口高龄化趋势及原因的国际比较分析

进入本世纪 ,在人口老龄化速度加快的同时 ,老年人口将呈现高龄化趋势。本文运用历次人口普查资料 ,对我国老年人口年龄结构及高龄老人规模变动趋势、成因及所带来的影响进行了分析。通过国际比较 ,对我国老年人口高龄化程度及高龄老年人口状况有一较客观的认识。与发达国家相比 ,我国老年人口高龄化进程在很大程度上受出生人口队列影响 ,同时死亡率下降的作用在逐渐增大。老年人口高龄化趋势将使孤寡老人及老年妇女问题尤为突出。     

美国、日本、韩国应对人口老龄化的经验及其启示

世界人口规模不断扩大,年龄结构类型也趋于老年型。但是发达国家与发展中国家有明显差异。发达国家人口老龄化程度高于发展中国家。本文以美国、日本、韩国三国为例,在考察人口规模争人口老龄化状况的基础上,总结了这些国家应对人口老龄化的主要经验,即政府重视人口老龄化问题;制定相应法律法规、方针政策;积极引导社会共同参与;不断完善老年社会保障制度。结合国情提出了对我国应对人口老龄化问题有益的启示。     

Population momentum expresses population aging

Population momentum and population aging occur when an initially growing population experiences a reduction in fertility to replacement level. Conceptually and empirically, momentum and aging express the same change, albeit on different scales. Fundamentally, they are two manifestations of the underlying process of demographic transformation. We consider three measures of aging over the transition to stationarity: the increase in mean population age, the decrease in the proportion under age 30, and the increase in the proportion over age 65. The three measures of aging are highly correlated, though the relationship to momentum is weakest for the increase in the proportion over age 65. We find that momentum is linearly related to aging. In both model and actual populations, a one-year increase in mean age translates into about 4.5% more population growth. The population below age 30 does not grow over the transition to stationarity, and the ratio of initial to ultimate proportions under age 30 is virtually identical to momentum.     

Demographic Conditions Responsible for Population Aging

This article develops and applies two expressions for the rate of change of a population's mean age. In one, aging is shown to be negatively related to contemporary birth rates and death rates. In a general sense, aging occurs when vital rates are too low, as illustrated through applications to the United States, the Netherlands, and Japan. The other expression relates the rate of aging to a population's demographic history, in particular to changes in mortality, migration, and the annual number of births. Applications to the United States and Sweden show that the dominant factor in current aging in these countries is a history of declining mortality. Migration also contributes significantly but in opposite directions in the two countries. The two approaches are integrated after recognizing that the rate of change in the mean age is equal to the covariance between age and age-specific growth rates. A decomposition of this covariance shows that the two seemingly unrelated expressions contain exactly the same information about the age pattern of growth rates.     

Curbing population growth: lessons from India

India was 1 of the 1st countries to establish a national population policy program to reduce the heavy social and economic burden of rampant population growth. The 1985 US Agency for International Development survey highlights 3 measures that could contribute significantly to the success of population policy and family planning goals: 1) increase the age at marriage for women, 2) lengthen the interval between births, and 3) improve communications. The younger a girl's age at marriage 1) the younger she is likely to get pregnant, 2) the more babies she can have over her lifetime, and 3) the higher the country's population growth rate. The answer to short birth intervals is childspacing through contraceptive methods. The Indian government has already begun to retrain its health workers and other functionaries to enhance their role as communicators. This should do much to counter the attitudes, practices, and lack of knowledge that contribute to India's population growth.     

Reply to Wachter

Although twins constitute only about 2.4 per cent of total births in less developed countries, they account for about 12 per cent of neonatal deaths and about nine per cent of infant deaths. Twin mortality in less developed countries has almost never been analysed systematically. We examine survival among twins as contrasted with that among singleton births by using 2692 twin observations pooled from 26 standardized Demographic and Health Surveys. Weakened by gestational and other biological complications, twins seem to be more vulnerable to detrimental demographic and household socio-economic influences than singletons. Twinning tends to amplify, or at least retain, whatever group differences exist among singleton births.     

A simple measure of fertility control

We describe a simple measure of fertility control: the proportion of all births from the age-specific fertility schedule that occurs among women by age 35. This measure has broad applicability because it does not require information on marital fertility rates. When both the proportion of births by age 35 and the most commonly used measure of fertility control, m, are calculated for a population over time, they are correlated very highly. Because of increasing levels of nonmarital fertility in several developed countries, measures of fertility control that are based on marital fertility are less appropriate now than in the past.     

Low fertility due to delay in -- not dearth of -- births

Population Council demographer John Bongaarts and his colleague Griffith Feeney argue that recent concern about a lack of births overlooks the fact that many women in developed countries are simply choosing to bear children later than women used to. So-called birth dearths are often caused by temporary delays in childbearing. The two demographers have designed a new way for demographers to account for the timing, or tempo, of childbearing in estimates of fertility. Their tempo-adjusted total fertility rate (TFR) allows demographers to correct skewed fertility trends, such as those leading to projections of birth dearths. The new measure provides a better indication of women's true propensity to bear children. Standard measures of fertility are distorted by changes in tempo. Such changes occur when large numbers of couples delay or accelerate their initiation of family building. The authors used historical data and theoretical arguments to validate the tempo-adjusted TFR, which improves upon the two common measures of fertility. Flaws in the TFR and the completed fertility rate (CFR) are corrected by Bongaarts and Feeney's new measure. To demonstrate their new tool, they examined the below-replacement fertility seen in recent decades in the US. By the mid-1990s, the TFR in almost every developed country had fallen below the replacement level of 2.1 births/woman, and in Italy, Spain, and Germany it fell below 1.5. If such fertility persists, declining population size, extreme population aging, and financial pressure upon social security systems may result. However, if fertility preferences hold at current levels, the very low fertility rates observed in the developed world will approach 2 children/couple.     

What is Happening with Quality of Life Among the Oldest People in Southern European Countries? An Empirical Approach Based on the SHARE Data

Population aging in developed countries has created new challenges to improve the well-being of individuals at different age cohorts. This issue is especially significant for Southern European countries, were aging societies have worse health and less socio-economic resources. The aim of this study is to contribute to this body of literature and to estimate the effect of aging on quality of life of oldest people. This paper uses the latest available data (6th wave) from the Survey on Health, Ageing and Retirement in Europe (SHARE). Specifically, robust ordinary least squares and multilevel regressions are employed to analyse the effects of socioeconomic, health, and community factors on quality of life among the oldest population for Southern European countries. Our findings confirm the significance of several factors on life satisfaction among the oldest population in this group of countries. Moreover, we show that the determinants which are correlated with quality of life include predisposing, health, geographic area and social isolation factors.     

Negative population growth: how to go about it? (Letter to the editor)

It proves an interesting exercise to try to determine the effects of a national policy of government control developed on the basis of the need to conserve scarce resources, lessen environmental pollution, and to reduce the U.S. population to 1/2 of the 1970 figures within 100 years without increasing the risks of death. Let it additionally be assumed that in order to minimize the required reduction of fertility that there be no net migration. At the end of the reduction process, the stationary state in stable equilibrium might hopefully be achieved. If these are the goals, the process would include 1) reduction of the annual stream of births immediately to the number that would ultimately be required to sustain a population 1/2 as large as the present number and 2) smooth decline of the totals but with constituent age groups shifting drastically as the sharply reduced stream of births spreads upward through the span of life, with those 65 years and older making up 12% of the population. To obtain a fixed annual stream of births from sharply changing numbers of women of childbearing age would require rapid and drastic changes in the rates of childbearing. The same reduced population could be obtained from a system involving less drastic changes in the age composition, but these means would not be positive ones for older individuals. Both fertility and age distribution could move more smoothly if the mortality risks increased or with considerable emigration of the aged. Other means of reducing the population to 1/2 the present size within 100 years would create even more turbulence in the age distribution and rates of childbearing than those just discussed.     

Population growth, development and the environment

When Population Studies was founded in 1946 a main preoccupation of demographers and of the public was the prospective decline of the British population, and the falling off of its quality because on the average a poor family had more children than a better-off one. Over the course of the 50 years interests have shifted to the aging of populations as births decline and mortality improves; immigration, immigrants being welcomed for the decades after the war, and subsequently facing hostile political pressures; environmental degradation and the spread of new diseases. The fall in the birth rate, required both for development and for protection of the environment, is spreading from the original industrialized countries of Europe and America to Asia, somewhat more slowly to Latin America, slowest of all to Africa.     

World population in transition

The world's population growth rate peaked at slightly over 2%/year in the late 1960s and in 1986 is down to 1.7% and falling. Annual numbers added continue to rise because these rates apply to a very large base, 4.9 billion in 1986. According to UN medium variant projections, world population growth will peak at 89 million/year in the late 1990s and then taper off until world population stabilizes in the late decade of the 21st century at about 10.2 billion. Close to 95% of this growth is occurring in less developed countries (LDCs) of Africa, Asia (minus Japan), and Latin America. LDC fertility rates are declining, except in sub-Saharan Africa and parts of Latin America and South Asia, but most have far to go to reach the replacement level of 2.1 births/woman. Fertility is below replacement in virtually all more developed countries. For LDCs, large numbers will be added before stabilization even after attainment of replacement level fertility because of the demographic momentum built into their large and young population bases. This complicates efforts to bridge gaps between living standards in LDCs and industrialized countries. From a new debate about whether rapid population growth deters or stimulates economic growth, a more integrated view has emerged. This view recognizes the complementary relationship between efforts to slow population growth and other development efforts; e.g., to improve health and education, upgrade women's status, increase productivity. Most effective in the increased contraceptive prevalence and fertility declines seen in many LDCs has been the combination of organized programs to increase access to family planning information and supplies with socioeconomic development that enhances the desire for smaller families.     

迁移与滞留：广东省人口老化的区域特征研究

论文描述了广东省人口老化的基本过程,分别从经济区、大城市、农村、外来人口聚集区与人口大规模外流区等多个层面上分析了人口老龄化的区域特征。指出了区域发展不平衡导致的青年人的流动和老年人口滞留在经济相对滞后的区域是影响人口老化区域差异的重要因素。     

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.     

Replacement Migration: A Questionable Tactic for Delaying the Inevitable Effects of Fertility Transition

This article critiques a recent U.N. Population Division report, Replacement Migration: Is it a Solution to Declining and Ageing Populations? The report explores the use of increased immigration to bolster future population size and change age distribution patterns in a group of developed countries. Fertility rate declines and lengthening life expectancies associated with demographic transition inevitably yield an aging population and a falling potential support ratio (PSR), a situation which some demographers and economists view with alarm. As the U.N. report itself suggests, replacement migration can only temporarily delay population aging and decline. These issues are ultimately better addressed through changes in retirement policy. Population projections should be used only with great caution in designing long-term demographic policy. In particular, some assumptions used to make the U.N. projections are questionable, and even minor changes in those assumptions would yield substantially different policy conclusions. Replacement migration also raises difficult environmental questions by moving large numbers of people from low to high per-capita consumption nations. Modest population decline, particularly in more developed countries, may have significant local and global environmental and climate policy benefits.

     

Europe's second demographic transition

By 1985, fertility rates in Europe were below the replacement level of 2.1 births/woman in all but Albania, Ireland, Malta, Poland, and Turkey, following a steady decline from a 1965 postwar peak well above 2.5 in Northern, Western, and Southern Europe and an erratic trend from a lower level in Eastern Europe. Natural decrease (fewer births than deaths) had begun already in Austria, Denmark, Hungary, and the Federal Republic of Germany and can be expected shortly in many other countries. According to current UN medium projections, Europe's population (minus the USSR) will grow only 6% between 1985 and 2025, from 492 to 524 million and 18.4% of the population in 2025 will be 65 and over. The decline to low fertility in the 1930s during Europe's 1st demographic transition was propelled by a concern for family and offspring. Behind the 2nd transition is a dramatic shift in norms toward progressiveness and individualism, which is moving Europeans away from marriage and parenthood. Cohabitation and out-of-wedlock fertility are increasingly acceptable; having a child is more and more a deliberate choice made to achieve greater self-fulfillment. Many Europeans view population decline and aging as threats to national influence and the welfare state. However, governments outside Eastern Europe, except for France, have hesitated to try politically risky and costly economic pronatalist incentives. As used in Eastern Europe, coupled with some restrictions on legal abortion, such incentives have not managed to boost fertility back up to replacement level. Immigration as a solution is unfeasible. All countries of immigration have now imposed strict controls, tried to stimulate return migration of guestworkers recruited during labor shortages of the 1960s and early 1970s, and now aim at rapid integration of minorities. Only measures compatible with the shift to individualism might slow or reverse the fertility decline, but a rebound to replacement level seems unlikely and long-term population decline appears inevitable for most of Europe.     

老年人口死亡概率时代变迁与老年定义的 重新思考

通过对1982-2010年间我国老年人口年龄别死亡概率的考察显示,近30年来我国老年人口的死亡概率随时间推移而不断降低,表明我国老年群体的健康状况和年龄内涵正在发生改变.与此同时,经济社会环境的变化和科学技术的发展极大地改变了老年人口的生活生产方式,也提供了更多的参与经济社会活动的能力与机会,从而使得后世代的老年人往往比前世代的老年人"更健康"、"更年轻",因此,有必要重新思考对老年人的传统定义.此外,中国老年人口死亡概率的变化也表现出明显的性别差异、地区差异以及与发达国家的差距,说明对中国来讲,要完成死亡模式的根本转化仍有很长的路要走.在充分认识这些差异性的基础上重新定义老年,将使得我们对老龄社会有一个全新的认识,也将有助于我们重构未来常态化老龄社会的公共政策体系.     

Population Growth,Development and the Environment

When Population Studies was founded in 1946 a main preoccupation of demographers and of the public was the prospective decline of the British population, and the falling off of its quality because on the average a poor family had more children than a better-off one. Over the course of the 50 years interests have shifted to the aging of populations as births decline and mortality improves; immigration, immigrants being welcomed for the decades after the war, and subsequently facing hostile political pressures; environmental degradation and the spread of new diseases. The fall in the birth rate, required both for development and for protection of the environment, is spreading from the original industrialized countries of Europe and America to Asia, somewhat more slowly to Latin America, slowest of all to Africa.     

A survey of population in the ESCAP region

In 1983, the ESCAP region added 44 million people, bringing its total population to 2600 million, which is 56% of the world population. The annual rate of population growth was 1.7% in 1983 compared to 2.4% in 1970-75. The urban population rose from 23.4% in 1970 to 26.4% in 1983, indicative of the drift from rural areas to large cities. In 1980, 12 of the world's 25 largest cities were in the ESCAP region, and there is concern about the deterioration of living conditions in these metropoles. In general, however, increasing urbanization in the developing countries of the ESCAP region has not been directly linked to increasing industrialization, possibly because of the success of rural development programs. With the exception of a few low fertility countries, a large proportion of the region's population is concentrated in the younger age groups; 50% of the population was under 22 years of age in 1983 and over 1/3 was under 15 years. In 1983, there were 69 dependents for every 100 persons of working age, although declines in the dependency ratio are projected. The region's labor force grew from 1100 million in 1970 to 1600 million in 1983; this growth has exceeded the capacity of country economies to generate adequate employment. The region is characterized by large variations in life expectancy at birth, largely reflecting differences in infant mortality rates. Whereas there are less than 10 infant deaths/1000 live births in Japan, the corresponding rates in Afghanistan and India are 203 and 121, respectively. Maternal-child health care programs are expected to reduce infant mortality in the years ahead. Finally, fertility declines have been noted in almost every country in the ESCAP region and have been most dramatic in East Asia, where 1983's total fertility rate was 40% lower than that in 1970-75. Key factors behind this decline include more aggressive government policies aimed at limiting population growth, developments in the fields of education and primary health care, and greater availability of contraception through family planning programs.