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.     

Sensitivity analysis of discrete-time interregional population systems

This paper shows analytically how (a) the long-run growth rate and (b) the long-run proportional distribution of an interregional population system with a time-homogeneous structural matrix are affected by small changes or errors in (a) the natural growth rates of individual regions and (b) the interregional migration rates. Furthermore, the analytic results are applied to an eight-region Canadian population system. Finally, it is claimed that the method introduced here can be easily applied to sensitivity analysis of both the intrinsic growth rate and the “stable” age-composition of the Leslie model with respect to changes in age-specific birth and survival rates.     

Lessons from stochastic small-area population projections: the case of Waikato subregions in New Zealand

Subnational population projections in New Zealand by means of the conventional deterministic cohort-component method have had a tendency to be conservative: underprojecting fast-growing populations and overprojecting slow-growing ones. In this paper we use a stochastic population projection method as an alternative. We generate population projections for five demographically distinct administrative areas within the Waikato region of New Zealand: Hamilton City, Franklin District, Thames-Coromandel District, Otorohanga District and South Waikato District. The results are compared to official subnational deterministic projections. The accuracy of subnational population projections in New Zealand is strongly affected by the instability of migration as a component of population change. Differently from the standard cohort-component method, in which net migration levels are projected, the key parameters of our method are age-gender-area specific probabilistic net migration rates. Generally, the identified and modelled uncertainty makes the traditional ‘mid-range’ scenario of subnational deterministic projections of limited use for policy analysis or planning beyond a relatively short projection horizon. We find that the projected range of rates of population growth is wider for smaller regions and/or regions more strongly affected by net migration. Directions for further development of the methodology are suggested.     

The stable population model,migration, and complementarity

The issue of declining population in many more-developed countries (MDCs) and continued rapid population growth in most less-developed countries (LDCs) is addressed in this paper. The authors expand the stable model theory beyond closed populations and apply it to situations where migration patterns are either in or out of a region. Through the use of the complementarity concept, the study illustrates what the impact of continued migration out of LDCs into MDCs would be on both regions.     

Diverging Demography: Hispanic and Non-Hispanic Contributions to U.S. Population Redistribution and Diversity

The substantial growth and geographic dispersion of Hispanics is among the most important demographic trends in recent U.S. demographic history. Our county-level study examines how widespread Hispanic natural increase and net migration has combined with the demographic change among non-Hispanics to produce an increasingly diverse population. This paper uses U.S. Census Bureau data and special tabulations of race/ethnic specific births and deaths from NCHS to highlight the demographic role of Hispanics as an engine of new county population growth and ethnoracial diversity across the U.S. landscape. It highlights key demographic processes—natural increase and net migration—that accounted for 1990–2010 changes in the absolute and relative sizes of the Hispanic and non-Hispanic populations. Hispanics accounted for the majority of all U.S. population growth between 2000 and 2010. Yet, Hispanics represented only 16 % of the U.S. population in 2010. Most previous research has focused on Hispanic immigration; here, we examine how natural increase and net migration among both the Hispanic and non-Hispanic population contribute to the nation’s growing diversity. Indeed, the demographic impact of rapid Hispanic growth has been reinforced by minimal white population growth due to low fertility, fewer women of reproductive age and growing mortality among the aging white population America’s burgeoning Hispanic population has left a large demographic footprint that is magnified by low and declining fertility and increasing mortality among America’s aging non-Hispanic population.     

Understanding the demographic implications of climate change: estimates of localized population predictions under future scenarios of sea-level rise

Significant advances have been made to understand the interrelationship between humans and the environment in recent years, yet research has not produced useful localized estimates that link population forecasts to environmental change. Coarse, static population estimates that have little information on projected growth or spatial variability mask substantial impacts of environmental change on especially vulnerable populations. We estimate that 20 million people in the United States will be affected by sea-level rise by 2030 in selected regions that represent a range of sociodemographic characteristics and corresponding risks of vulnerability. Our results show that the impact of sea-level rise extends beyond the directly impacted counties due to migration networks that link inland and coastal areas and their populations. Substantial rates of population growth and migration are serious considerations for developing mitigation, adaptation, and planning strategies, and for future research on the social, demographic, and political dimensions of climate change.     

Differences in the Environmental,Social and Economic Development of Polish–Lithuanian Trans-Border Regions

Regional development is a complex process that can be analysed in various contexts, including environmental, social and economic factors. Variations in the levels of development are naturally observed across countries and regions, but they play a special role in trans-border regions. The aim of this study is to investigate differences in the level of development of two Polish voivodships (Warmia and Mazury, and Podlasie) and two Lithuanian counties (Marijampol? and Alytus) which are trans-border regions (NUTS 4 level). The study was conducted by analysing three subordinate criteria, namely environmental, social and economic factors, as well as the overall development of the evaluated regions with the use of the analytical hierarchy process and technique for order preference by similarity to ideal solution methods. The evaluated trans-border regions are characterised by a predominance of rural areas and considerable variations in development. The entire area is characterised by high natural value. This is an important observation because the condition of the natural environment is a key determinant of well-being, and it directly influences the quality of life. The analysis revealed considerable demographic problems, mainly in Lithuanian regions, resulting from low population growth and a negative net migration rate which influence population structure. Disproportions in regional development call for regional policies that are adapted to local needs and resources.

     

Population and family planning of minority groups]

The population of minority groups has been increasing rapidly in recent years, but the rate of increase is different depending on the region, for various reasons: 1) Population increase rates are high in flat, low regions with warm weather, a good natural environment, and good transportation systems. Productivity is beginning to lag behind population growth (population increased by 90% from 1953 to 1982). 2) Population is increasing at a slower rate in high regions with cool weather and an average natural environment. The productivity growth rate in these regions is about the same (the population increased by 37.5% from 1949 to 1980). 3) Population is increasing at a lower, or even negative, rate in mountainous regions with little flat land and poor transportation service. 4) In some regions, large families are predominant because of tradition and/or religion. In some minority groups, where large extended families are the rule, increases are low because of health problems. People in minority groups are willing to practice family planning, but it is impossible to make one general family planning policy because people in different regions face different problems.     

中国西部民族地区的人口生育与死亡状况浅析

西部民族地区包括中国少数民族人口最集中的8个省区,少数民族人口占全国少数民族人口的63.41%。受到这些地区本身历史的、自然的、民族的、以及社会经济发展水平等多种因素影响,其人口状况也表现为与中国中、东部很大的不同,具有自身显著的独特性。本文通过对历次人口普查资料和有关统计数据的分析,对中国西部民族地区的人口变动以及自然增长状况进行了系统地分析,得出了一些有意义的结论。     

Urban Growth in Developing Countries: A Review of Projections and Predictions

Comparison of the United Nations' earliest and most recent projections to the year 2000 suggests that urban and city growth in developing regions has occurred much more slowly than was anticipated as recently as 1980. A modified “urban population explosion” in developing countries since the 1970s conforms to explanatory models of urban growth developed by economists around 1980. Trends in productivity and terms of trade, in particular, have been highly favorable to agriculture as compared to manufacturing, presumably slowing migration to urban centers. Increases in national population growth rates have produced less than commensurate increases in rates of city growth, further supporting an economic and migration-related explanation for unexpectedly slow recent urban growth. Despite the efforts of the United Nations to maintain reliable statistics on urban and city populations, urban population projections should be interpreted with caution because of inadequacies of the data on which they are based. Moreover, current projections that virtually all world population growth in the future will occur in urban areas of developing countries may be misconstrued, if the forces that have retarded urban growth in recent years persist.     

Evaluation of Alternative Cohort-Component Models for Local Area Population Forecasts

It is generally accepted by demographers that cohort-component projection models which incorporate directional migration are conceptually preferable to those using net migration. Yet net migration cohort-component models, and other simplified variations, remain in common use by both academics and practitioners because of their simplicity and low data requirements. While many arguments have been presented in favour of using one or other type of model, surprisingly little analysis has been undertaken to assess which tend to give the most accurate forecasts. This paper evaluates five cohort-component models which differ in the way they handle migration, four of which are well known, with one—a composite net migration model—being proposed here for the first time. The paper evaluates the performance of these five models in their unconstrained form, and then in a constrained form in which age–sex-specific forecasts are constrained to independent total populations from an extrapolative model shown to produce accurate forecasts in earlier research. Retrospective forecasts for 67 local government areas of New South Wales were produced for the period 1991–2011 and then compared to population estimates. Assessments of both total and age-specific population forecasts were made. The results demonstrate the superior performance of the forecasts constrained to total populations from the extrapolative model, with the constrained bi-regional model giving the lowest errors. The findings should be of use to practitioners in selecting appropriate models for local area population forecasts.     

Migration - a mixed blessing

Regarding migration, the current thinking is that certain aspects of migration have important implications for population planning. Focus here is on the role of migration and its influence on integrated development programs. Although individuals who migrate to cities are generally from the more privileged socioeconomic groups within the rural area, it is not accurate to identify them as the "cream of the rural population." Present population policies do consider the fact that 70 to 80% of the people live in rural areas, yet population policies give only lip service to migration policies. In response to a question as to whether urbanization is conducive to pro- to anti-natal tendencies in migrating families the responses varied. 1 opinion was that there is no evidence that urbanization and the natality behavior of migrating families is significantly related, while other opinions identified a relationship between anti-natal behavior and migration. Rural development and rural growth centers do seem to help alleviate population problems of rural and urban areas, but their success is very dependent on the kind of rural development programs and the extent of services provided through the growth center. The following are among the advantages to "planned migration" that can be used to strengthen population policies: 1) effective utilization of manpower; 2) balanced regional development; 3) further exploitation of natural resources; and 4) reducing the various problems in urban regions. Many do believe that international migration is a feasible solution to population problems in the global context.     

A problem in household composition

"Distinction made between household-persons and household-markers [the person who identifies the family or household as a unit] is formalized in the notion of nested populations. This leads to an extension of the Leslie model into a formulation of growth for both population and households. The extended model involves the matrix presentation of household composition where ratios of household-persons who are age 0, per household-marker, function as surrogate values for fertility rates. The extended model describes change over time in the distribution of population by age, and in the distribution of households by age of household-marker, or household-head. The model involves the inversion of a nonnegative matrix, and is feasible only if it yields, projected over time, nonnegative entries in vectors representing distribution of population by age, and distribution of household-heads by age. Conditions for the feasibility of the extended model are discussed, and a sufficient condition for feasibility over a single interval is identified." (SUMMARY IN FRE)     

[A preliminary analysis of the migration of urban populations in China].]

The author presents an analysis of migration of urban populations from 1951 to 1986 in China. Size and direction of urban migrant populations and the reasons for migration are included. The rural-urban migration is described as relatively stable in size and controlled by national political factors, economic conditions, and an urban population growth policy.     

我国人口迁移大势和胡焕庸线思考

本文对2005－2010年间我国东中西部地区的人口净迁移流量作了两种推算：一是根据“六普”资料直接推算,二是按地区人口增量扣除自然增长量的方法间接推算,发现两种推算结果有较大出入。推算结果还显示：5岁以下儿童的净迁移流向正好与“一江春水向东流”的大势相反。笔者认为：胡焕庸线破与不破两难,主要难在人口东迁难以突破性逆转。人口均衡分布之义,在于“均而不衡,衡而不均”,过份追求均匀分布,只会加剧人口与经济社会、资源环境的不平衡。区域人口与经济－资源承载力的相对平衡,应着力寻求区域内平衡和跨区域平衡之间的最佳平衡点。     

Climatic change and migration from Oceania: Implications for Australia,New Zealand and the United States of America

It is possible that climatic change may stimulate population movements as people turn to migration as one strategy of adaptation. This paper attempts to assess possible migration flows which may occur, in response to climatic shifts over the next thirty years, from small island states in the south-west Pacific ocean region to the United States, Australia and New Zealand. It is argued that the small island states appear vulnerable to climatic change, with low coral atolls being most at risk. Adverse impacts of climatic change will be one extra pressure on small island states, many of which are already struggling to cope with sustainable management of their natural resources and with the demands of their rapidly growing populations for education, housing and employment. The migration strategy is likely to entail significant medium-term health, psychological and social costs for some Pacific island migrants as they try to move or cope with life in western industrialised societies.     

A look at Philippine population in the year 2000

The major subject areas explored by the University of the Population Institute were fertility, mortality, the Filipino family and nuptiality, migration and urbanization, and the structure and growth of the labor force. Data were extracted primarily from the Philippine Censuses (1903-1970) the National Demographic Surveys of 1968 and 1973, and special surveys conducted by the Institute research team. On the basis of the findings, a range of alternative population futures is projected for the year 2000, with their respective policy implications. The estimate of the crude birthrate for 1970 placed the range at between 39.3 and 42.7. The crude birthrate may have declined by 21-23% in the last 70 years, and by almost 13% in 1960-1970 alone. On the national level, fertility rates will continue to decline if the trend of delayed marriages continues. Fertility was found to decrease with the introduction of the positive socioeconomic factors that make some regions more developed than others. The present low levels of mortality have decreased its importance in relation to fertility. Mortality prospects can be improved by several policy actions which are presented here in the order of priority. Current evidence points strongly to an increase in the proportion of single individuals who delay marriage and those not planning to marry at all. The record of internal migration in the Philippines during the 20th century has been dominated by the phenomenon of urbanization, which increased from 13% in 1903 to 33% in 1970. An effort needs to be made to achieve greater rural-urban balance. The country's high population growth has increased the number of job seekers in recent years; the expansion of the regional labor force in the 1960-1970 decade was highly correlated with the growth of regional populations. Fertility, mortality, nuptiality, migration, and urbanization are the major factors determining the growth and structure of Philippine population. Alternative projections for each of these factors were combined in different ways and 3 alternative scenarios for population in the year 2000 are presented.     

Prospects for international migration: Globalization and its discontents

The paper challenges the view that the late twentieth century is the ‘age of migration’. For developing countries, flows of out-migrants are small compared with population growth, although in developed countries the stock of immigrants increased in proportion to the total population between 1965 and 1990. Despite the importance of refugee movement, the main force for international migration is economic. Why do not more people migrate (internally and internationally) to take advantage of potential economic gains? For international migration, one deterrent is institutional barriers against uncontrolled immigration. Different interest groups stand to gain or lose from increased migration. The income-enhancing effects of unhindered international labour migration, measured jointly for sending and receiving countries and by extension globally, should be very large. Even partial liberalization of immigration to industrialized countries would serve developing countries well. In industrialized countries, however, there is concern about the effect of massive labour inflows on the ethnic, religious and cultural composition of the population and its social cohesion. In some countries, migration is leading to greater ethnic mingling; in others there is a recrudescence of nationalistic aspirations for independent statehood with ethnically homogeneous populations, or to preserve the advantages of economically successful subregions.     

中国人口年龄结构特征与变化趋势分析--基于1995～2014年数据的实证研究

人口年龄结构是经过多年人口自然增长和迁移变动等综合作用而形成的客观状况,对未来人口发展的速度和趋势以及国家或地区经济社会整体发展产生重要影响。本文通过对1995～2014年数据的实证分析,发现20年来我国人口年龄结构呈现以下特征：少儿人口数量减少且比重呈持续下降趋势;劳动年龄人口数量稳步增长且比重呈稳定上升趋势;老年人口数量持续增长且比重呈上升趋势,老龄化进程加快。总体人口年龄结构呈现老年型,各地区人口老龄化程度存在差异。各地人口负担系数存在较大差异,人均GDP与总抚养比和少年儿童抚养比呈负相关,与老年人口抚养比呈正相关。经济发达省市区人口负担系数较小;城乡人口比例呈持续升高态势;城乡人口总抚养比和少儿抚养比呈下降趋势,城乡老年人口抚养比呈稳步升高态势;乡村人口抚养比高于城镇。     

On some theoretic issues about planned control of population]

There are basic differences between Marxian and Malthusian population thought: 1) For Marx, population is a social phenomenon--human reproduction belongs to social production and population laws are social laws influenced by the means of production. Marx recognized that human reproduction had both a natural and a social relationship, but Malthus population theory only acknowledges the natural relationship of human reproduction. Malthus believed that if population grows without interference, it will double every 25 years, or geometrically. It is evident Malthus substituted biological possibilities for the objective inevitability of population evolution, and natural population laws for social population laws. 2) Marx believed that social production is the unification of material production and human reproduction. Material production is controlled and necessitates control of human reproduction. For Malthus, the growth of the means of subsistence never catches up with the growth of the population, but Marx said that even though land is limited, the development of production forces is limitless. Marxist theory postulates that man is basically a producer, but that population must be planned because not everyone is a producer (e.g., children and the unskilled). 3) Malthus believed that in capitalistic countries unemployment, famine, and poverty stem from too many births by the laboring class, i.e., population determines the economy. The only solution to population problems is to have fewer children. For Marx, economics determines population problems.