Consistent correction of data for aboriginal populations

A consistent correction procedure is used to determine improved, consistent estimates by sex of census age distributions, intercensal births, intercensal deaths and net migration by age for the Aboriginal populations of the Northern Territory, South Australia and Western Australia during the period 1986–91. Undercount estimates and life tables show the Aboriginal populations to have lower coverage in statistical collections and much higher death risks than the total Australian population. Inter-regional net migration estimates show that component of change can no longer be ignored.     

Why populations persist: mobility,place attachment and climate change

Explanations of relationships between migration and environmental change now focus on multiple interactions, risks in destination and immobility. This research applies behavioural migration theory to examine the extent to which immobile populations experiencing environmental degradation exercise agency with respect to location and, in doing so, elucidates what it means to be trapped. This research uses individual survey data from a migrant-sending area in highland Peru where the population experiences negative health and livelihood impacts from climate-related phenomena. Analysis of these data reveals three reasons for non-migration: high levels of satisfaction, resource barriers and low mobility potential. Immobility in dissatisfied people is more likely to be caused by attachment to place than resource constraints. Thus, the results suggest that trapped populations exist along a continuum. This highlights the need for policy responses differentiated by the mobility characteristics and preferences of the individual. Caution, therefore, must be exercised when labelling populations as trapped and promoting relocation.     

The uneven geography of research on “environmental migration”

Climate change and environmental hazards affect the entire world, but their interactions with—and consequences on—human migration are unevenly distributed geographically. Research on climate and migration have their own geographies which do not necessarily coincide. This paper critically confronts these two geographies by presenting the first detailed mapping of research in the field of environmentally induced migration. After a brief review of the geography of research on climate change, the paper presents an overview of nearly 50 years of case studies on the basis of CliMig, a bibliographic database of 1193 scientific papers and books on climate/environmental change and migration, among them 463 empirical case studies. We analyze the locations of these case studies, the academic affiliations of their researchers, and the origin of their funding. Mapping the locations of case studies worldwide points toward blind spots in the research and identifies “overstudied” areas. We describe the methodologies used in the studies and present a typology of environmental hazards. Our results show that research on environmental migration is mainly done in countries of the Global South, whereas climate science research in general is focused on countries of the Global North. We contend that the peculiar geography of environmental migration cannot be explained solely by the uneven vulnerability of southern populations to the environment. It must also be understood through the lens of post-colonial and securitization studies as the result of a framing of “environmental refugees” (and refugees in general) as an intrinsically “southern problem” and as a security risk for the North. This paper is an original contribution to the literature on the North-South divide in scientific research and will help to outline future directions of investigation.     

Climate change and internal migration intentions in the forest-savannah transition zone of Ghana

Migration is at the centre of demographic research on the population–environment nexus. Increasing concerns about the impacts of environmental events on human population are fuelling interest on the relationship between migration and environmental change. Using data from the Climate Change Collective Learning and Observatory Network Ghana project, we employ binary logistic regression to examine migration intentions of households in response to major community stressors including climate-related ones. The results indicate that the type of community stressor that affects households most does not differentiate migration intentions in Ghana’s forest-savannah transition zone: Even though the majority of the respondents mentioned climate-related events as the stressor that affects them the most, such events do not appear to directly explain migration intentions. However, socio-demographic factors such as age, household size and current migration status are significant predictors of migration intentions, with younger household heads, heads of migrant households and heads of smaller households being relatively more likely to have migration intentions than other household heads. We conclude that migration drivers are multifaceted and deserve further research because even in areas with perceived environmental stress, climate-related events may not be the primary motivation for migration intentions.     

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.     

Estimation of local demographic variation in a flexible framework for population projections

A cohort component projection of local populations based on sex and single year of age offers great value for planning local services, but demands data beyond the detail available. Local fertility, mortality and migration schedules by age and sex must be estimated sensitively to local variation if the results are to be of greater value than simpler methods of projection. Two approaches are compared, using data for the recent past: (a) direct estimation of local area age-specific schedules of fertility, mortality and migration based on data available to the national statistical agency; (b) graduation of national schedules using only local area population estimates by age, total numbers of births, and total numbers of deaths; age-specific migration is indirectly estimated from successive population estimates. These two approaches are compared with a projection using the same rates for each area. The three projections have been implemented for electoral wards in the Fife local government area of Scotland, using the flexible framework provided by POPGROUP software. Persuasive local population projections based on standard data for standard areas are feasible without the regular publication of migration flows.     

Environmental Influences on Human Migration in Rural Ecuador

The question of whether environmental conditions influence human migration has recently gained considerable attention, driven by claims that global environmental change will displace large populations. Despite this high level of interest, few quantitative studies have investigated the potential effects of environmental factors on migration, particularly in the developing world and for gradual but pervasive forms of environmental change. To address this, a retrospective migration survey was conducted in rural Ecuador and linked to data on topography, climate, and weather shocks. These data were used to estimate multivariate event history models of alternative forms of mobility (local mobility, internal migration, and international migration), controlling for a large number of covariates. This approach is generalizable to other study areas and responds to calls for the development of more rigorous methods in this field. The results indicate that adverse environmental conditions do not consistently increase rural out-migration and, in some cases, reduce migration. Instead, households respond to environmental factors in diverse ways, resulting in complex migratory responses. Overall, the results support an alternative narrative of environmentally induced migration that recognizes the adaptability of rural households in responding to environmental change.     

America's diversity and growth: signposts for the 21st century

This report provides a summary of the US demographic and population trends in the 21st century. It gives objective information on population growth, the determinants of population change, residential trends, racial and ethnic diversity, age profile, family life, households and families, measures of well-being, and future prospects. It is shown that US population is growing through relatively high fertility, migration and increasing life expectancy. Longer life expectancy has had a significant effect on American family life. Immigration fuels rapid population growth and social change creating increased ethnic diversity. Family life pattern also shifted, early marriage is replaced by cohabitation and divorce rates are increasing resulting in increased number of single-parent families. Many Americans have prospered well beyond their expectations; educational attainment vastly improved; more people moved out of poverty and more working women indicates a change in the workforce trends. Overall, it is noted that the US population will continue to grow. Prospect of such robust growth intensifies concerns about pollution and other environmental threats. At the same time, it seem that population growth is inextricably linked to the nations's prosperity.     

First Impressions from the 2000 Census of China

The 2000 census of China has several notable innovations, including a sample long form containing detailed items on migration, housing, and employment. Preliminary data indicate rapid urbanization and continued rapid social change in the 1990s, and apparent success in the government's drive to curtail population growth. Although a post‐enumeration survey indicates that overall data quality is good, the rise of a mobile “floating population” and pressures of the birth planning program caused problems for the enumeration of migrants and infants. Data released to date have been silent on two important issues, fertility and rising sex ratios.     

Population growth, age structure, and environmental impact

We develop and use a simulation model that considers sustainability on several levels by calculating production, consumption, investment, population growth/change, and environmental pollution less environmental quality upgrading investment. Our model allows us to consider population's impact on per capita consumption as well as the social interdependencies among populations, per capita consumption, and technology. Under certain population growth scenarios we find some countries ultimately consume less pollution, and less pollution is consumed on a system-wide basis. We arrive at this apparently counterintutive result because: (1) we explicitly model the decision to invest in environmental quality upgrading; and (2) we consider the impact of population age structure on investment, not only the impact of total population and population growth on total consumption.     

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.     

Aristotle and Open Population Thinking

Aristotle's Politics contains the most extensive consideration of actual populations to survive from Antiquity. Population, for Aristotle, is a logistics of memberships. The size, fertility, and other properties of a state's population are determined by relationships among the several subpopulations that it comprises. This approach gives rise to a comprehensive logic that addresses many policy concerns of modern demography, yet within fundamentally different ideas of quantification and structure. Some of this logic fits easily with current demographic thinking. Relations among sub‐populations, for example, play a crucial role in population change because they are conduits of communication and reflect differences in education. Aristotle's method stands in contrast to modern demographic thinking, however, in treating migration, inequality, and the mutability of population memberships as primary processes of population change. Given that interest in this conjunction of issues is now central to the demography of globalization, there is added reason to consider Aristotle's insights as complementary to modern population studies. His principal case study, the constitution of Athens, illustrates the development of his thought.     

Migration stock and the issue of competing and complementary flows in United States interstate migration

The purpose of this paper is to study the determinants of interstate migration in the United States from 1965–1970 when a new change in direction of migration has started, and to examine the flow creation or flow diversion that results from migration to some appealing regions. Several related variables have been selected and tested for gross interstate migration flows. The results show that overall both push and pull factors have not been important. People from higher income regions migrate more, and migrants tend to move to states with higher incomes and larger population. Distance was not found to act as a significant deterrence to migration, whereas population density of origin and destination was significant. Previous migration was found to have a very strong effect on migration. The results of the study also suggested that there has been a major change in the location of growth areas in the United States during 1955–1970.The study of concurrent flow showed that the states of Texas, Louisiana, Mississippi, Alabama, Georgia, and Florida combined have positively influenced migratory flow between origin and destination states. Empirical results, however, also showed that California did not have flow creation or flow diversion effects on interstate migration.This research was supported partly through Organized Research Funds of The University of Texas at Arlington.     

The forecast accuracy of Australian Bureau of Statistics national population projections

This paper examines the forecast accuracy of Australian Bureau of Statistics national population projections produced from the 1960s to the early 2000s. As well as total populations, the accuracy of the following is assessed: age-sex-specific populations, the Total Fertility Rate, life expectancy at birth and net international migration. It is shown that forecasts of the 1960s and 70s were the most inaccurate; forecasts of the 1980s and later proved to be much more reliable. The paper goes on to take an alternative perspective on population forecast error through the use of an adapted percentage error measure which accounts for offsetting errors in births, deaths, net migration and the jump-off population. This measure also permits an assessment of the relative contributions of the components of demographic change to overall inaccuracy. It is shown that errors in forecasting net international migration have generally contributed most to inaccuracy followed by births and then deaths and jump-off error. ABS projections of total population are also compared to those produced using a simple naïve model. The paper concludes by arguing that the new error measure could prove valuable in other studies of population forecast accuracy.     

Elder Care and Migrant Labor in Europe: A Demographic Outlook

This article examines the demand for migrant labor in older‐adult care as one of the key aspects of the aging and migration nexus. It reviews the demographic determinants that have shaped demand for and provision of older‐adult care across Europe. Using the EU Labour Force Survey, new comparative estimates are generated on the employment of migrants in care occupations and the channels of entry into the European labor market. Projections on demand for and supply of care to the older population reveal a future gap in both formal and informal provision. It is shown that, owing to institutional, economic, and social constraints, the significant growth of the care workforce that will be required to meet the future needs of Europe's aging populations is unlikely to be achieved by relying exclusively on EU labor supply. The conclusions outline some implications for future immigration policies.     

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.     

Multiple Migration Flows of Romanians

Abstract

Most studies on international migration examine population movement between a country of origin and a destination. This article aims to show that migrants often change destinations, a less studied pattern of ‘multiple migrations’. This article explores how such migration occurs and analyses the variables accounting for it. Drawing on qualitative fieldwork research amongst Romanian migrants in Portugal, the article concludes that the growth in multiple migrations of Romanian migrants throughout Europe can be explained by a combination of migration policies and social networks, mediated by migrants’ level of education and type of occupation at the destination.     

Effect of census errors on the measurement of net migration

This paper traces the history of the use of vital statistics, survival rates, and ratios in the estimation of net migration from one decade to another. Net migration studies by Hart (1921); Baker (1933) ; Hamilton (1934); Thornthwaite (1934); Lively and Taeuber (1939) ; Henderson (1943); Hamilton and Henderson (1943); Hamilton (1951); Siegel and Hamilton (1952); Lee and Bowles (1954); Price (1955); Lee, Miller, and others (1957); Hamilton (1959); Zachariah (1962); Tarver (1962); Shryock (1964); Eldridge (1965); Hamilton (1965); and the United States Census Bureau are cited as the principal users of various residual methods of estimating net migration. All these demographers have either implicitly or explicitly recognized that errors in census enumeration and in the registration of births and deaths have been reflected in errors of estimated net migration.The underlying characteristic of all the methods used by these demographers has been the estimation of net migration as a residual obtained by subtracting natural increase in an area during a decade from the population change during the same decade. This method has been most generally stated in the classic formula {fx394-1} This formula has been used both with total populations and with aging cohorts. The principal variations of the basic formula have involved the use of life table and census survival ratios as a means of measuring natural increase (B - D), or of estimating "expected" populations assuming no migration. The main points of controversy have involved life table v. censm survival ratios, assumptions regarding the similarity in national and state census enumeration errors, and ways and means of estimating the errors involved in estimates of migration and of migration rates by the various methods.Daniel O. Price (1955) and Zachariah (1962) made important mathematical contributions and attempted to evaluate the errors involved in the me of census survival rates. Eldridge (1965) discovered that, in the United States between 1950 and 1960, the use of the census survival rate method usually gave much lower estimates of net migration than did the classic vital statistic method. Hamilton (1965), using some suggestions by Hope T. Eldridge, developed a mathematical theory or explanation of not only why the CSR estimates were usually lower than the VS estimates but also why the CSR estimates would usually give closer estimates on the true net migration than would the EVS method, which itself is subject to errors of census enumeration and of underregistration of births and deaths. The author also discusses the effect of improvement in census enumeration between 1950 and 1960 on estimates of net migration and derives a generalized formula which takes the timing of migration into consideration.The author acknowledges with sincere appreciation important constructive suggestions made by Dr. Hope T. Eldridge, Population Studies Center, University of Pennsylvania, and the authors of the many papers used as original material. This paper is a revision of a paper read before the annual meeting ot the Population Association of America, Hotel Roosevelt, New York, New York, April 29-30, 1966. Contribution from the Departments of Sociology and Experimental Statistics, North Carolina Agricultural Experiment Station, North Carolina State University. Published with the approval of the Director of Research as Paper No. 2227 of the Journal series.     

Urban growth in China: past, prospect, and its impacts

Rapid growth and globalization of the domestic economy have dramatically accelerated urbanization in China, resulting in significant environmental impacts and challenges for sustainable development. Using a multistate model accounting for distributional aspects of age, sex, education, and migration in rural and urban regions, we estimate the magnitude of urbanization in China through 2030 and examine some major associated sustainability issues. Results indicate that: (1) for a range of assumptions, China’s urban population will nearly double from 2000 to 2030; (2) the labor force will constitute a larger share of total population in urban areas than rural due to internal migration of younger workers—this appears particularly true for the mega-urban metropolises of Beijing and Shanghai; (3) rural populations will experience more aging than urban; and (4) level of education among China’s rural labor force will remain low, which could pressure China’s industrial structural transition from an agricultural to a service-based economy.     

Elementary models for population growth and distribution analysis

A version of the Lotka-Volterra interaction model is adapted to describe population growth and migration processes in a two-region system. The regions are identified as a metropolis and its non-metropolitan hinterland. Several conditions on growth and migration regimes are imposed. The time behavior of the systems are analyzed, noting especially situations where total depopulation or population explosion eventually occur in one or both populations. Neither growth control nor migration control alone results in a condition of long-run stability in both regions. If at least a momentary condition of zero growth is achieved in both regions, it is possible to maintain finite populations if each population follows a logistic natural growth process and migration flow is proportional to the volume of interaction. It is necessary also that the natural increase limitation is strong relative to migration rates. This result holds even if one population has a net migration advantage over the other.