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At least 19 recordsLinked to original sources
PubMed1999

The new subnational population projections model: methodology and projection scenarios.

This article describes the most recent process of projecting population at the subnational level in England. It briefly explains the reasons why projecting population at the subnational level is important, describes the model and how it was used to produce the latest set of long-term subnational population projections in England published by the Office for National Statistics (ONS) in 1998. The article then discusses how the model may be applied to answer various 'what-if' questions about future population.

Adolescent↗
PubMed1987

A survey of Census Bureau population projection methods.

"Population projections methods of the U.S. Census Bureau draw upon several different traditions of forecasting: demographic accounting, judgmental, time series, deterministic, and explanatory. This paper reviews each of the forecasting traditions in population projections, describes the U.S. Census Bureau's current methods for national and state population projections, and proposes new hybrid approaches such as demographic-time series methods for national fertility projections and economic-demographic methods for state migration projections. Throughout the article, possible parallels with forecasting in other disciplines are noted."

Americas↗
PubMed1982

Long-range global population projections, as assessed in 1980.

UN medium range projections prepared in the 1980 assessment projected the population of individual countries up to the year 2025. The long range projections discussed here were prepared by projecting the population of 8 major world regions from 2025-2100. The purpose of the projection was to observe the implications of the changes from the 1978 assessment made in the 1980 medium range projections on the long range projections of the world's populations. As in previous projections, high, medium, and low variants were prepared in which fertility is assumed to be constant at the replacement level but at different times in the future. In addition, these projections contain 2 variants not previously prepared--namely, the growth and decline variants, in which the ultimate net reproduction rate is 1.05 and 0.95, respectively. In all the variants, expectation of life at birth is assumed to reach 75 years for males and 80 for females. According to the current medium variant projection, the earth's population will become stationary after 2095 at 10.2 billion persons, compared with a total of 10.5 billion projected in the 1978 assessment. The lower projection is largely attributable to a recent decline in the growth rate of several countries in South Asia which was greater than previously assumed. When the world population becomes stationary, both crude birth and death rates would be about 13/1000. In the decline variant, total population would peak at 7.7 billion in 2055, then decline gradually to 7.2 billion in 2100. The total population as projected by the growth variant would equal 14.9 billion in 2100 and would still be growing slowly. Between 1980 and 2050, 95% of the world's growth will occur in the currently less developed regions. Their share of total population will increase from 75-85% during that period. The age structure in all regions is expected to converge to 1 in which the median age is 39 years, the proportion both below age 15 and above age 64 is about 19% each, and the dependency ratio is about 60. A precise degree of accuracy cannot be specified, but the argument is made that the actual future population of the world is very likely to fall within the range of the projection variants and probably not far from the medium variant.

Africa↗
PubMed1992

Immigration and immigrant generations in population projections.

This paper proposes a new model for population projections. This model projects an initial population under conditions of fertility, mortality, and international migration (like standard cohort-component models), but considers the population arrayed by generation. The model incorporates 4 generations: a foreign-born first generation (the immigrants), a second generation (sons and daughters of immigrants), a third generation (grandsons and granddaughters of immigrants), and fourth-and-higher generations. The model requires fertility, mortality, and migration equations by generation, which take a somewhat different form than in conventional cohort-component population projection. Consideration of the model also makes apparent that assignment of births to generations may not follow a simple form: the paper presents a method for including the empirical description of intergenerational births within the generational framework. As an example, the authors examine the next century of population growth for the Asian, Black, Hispanic, and White non-Hispanic populations in the US, comparing their growth rates and their composition within the total US population. With annual net immigration of 950,000, the total US population of 249 million in 1990 will top 400 million in 2070 and reach about 432 million in 2090. Thus, the level of immigration and emigration assumed in these projections suggests considerable population growth for the next hundred years. The racial/ethnic composition of the US will shift markedly during the next century, as described in the paper.

Americas↗
PubMed1986

Evaluation of international population projections: lessons and experiences.

Global and regional population projections produced by the United Nations are evaluated and compared with actual population estimates. While general observations pertaining to the global level are made, the focus is on Latin America for selected years from 1950 to 1980. It is found that "the quality of population projections improved since 1950. In addition, short-term projections are found to be relatively more accurate than those for the long-term.... In the medium- or long-term projections, at least in the Latin American case, the assumptions regarding mortality were far from the real situation. The important factors in the projections are found to be in the order of base population, fertility and mortality."

Americas↗
PubMed1987

Demographic heterogeneity and uncertainty in population projections.

Recent developments in a class of stochastic population processes were used to study the impact of demographic heterogeneity on the uncertainty of population projections. Selected for study by computer simulation were population projections for East Africa designed to quantify opinions regarding expected fertility and mortality declines. Since both fertility and mortality declined in these projections, their laws of evolution may be described as time inhomogeneous. The computer simulation studies reported in this paper strongly suggest that randomized laws of evolution should be taken into account in further developments of population projection methodologies designed formally and computationally to accommodate uncertainty. Variability in fecundability, the kind of demographic heterogeneity studied in this paper, is only one aspect of these randomized laws.

Africa, Eastern↗
PubMed2000

[Population projections: goals, methods, hypotheses].

Population projections generally use the component method which consists in adapting sample size by age and sex from mortality, fertility and migration hypotheses. This exercise is not always aimed a providing projection data, but may also serve to analyze factors changing in the population. Comparatively long-term demographic forecasts, particularly for mortality, can be made due to the major inertia of demographic phenomena. However, the quality of such predictions depends on the quality of knowledge of past evolution in the demographic factors and on the capacity to forecast their future evolution.

Adolescent↗
PubMed1988

Confidence intervals for population projections based on Monte Carlo methods.

"This paper presents an approach of constructing confidence intervals by means of Monte Carlo simulation. This technique attempts to incorporate the uncertainty involved in projecting human populations by letting the fertility and net immigration rates vary as a random variable with a specific distribution. Since fertility and migration are by far the most volatile, and therefore, the most critical components to population forecasting, this technique has the potential of accounting for this uncertainty, if the subjective distributions are specified with enough care. Considering the results of the model for the U.S. in 2082, for example, it is shown that the population will number between 255 million and 355 million with a probability of 90 percent."

Americas↗
PubMed1995

1993-based subnational population projections for England.

The populations of the shire counties and Greater London are projected to increase in population between 1993 and 2001. In contrast the populations of the metropolitan counties are expected to remain fairly static. This article gives details of the 1993-based subnational population projections for local authority areas within England.

Adolescent↗
PubMed1993

A numerical method of population projection.

"In this paper a numerical method has been developed to project the total population of a geographical region. The method has been applied to the Indian situation. It is found that the total population of India was expected to lie between [836 million and 850 million in 1991 and between 986 million and 1,042 million] in 2001."

Asia↗
PubMed1992

Population projections for the countries of the European Community.

"Methods and results of different population projections for the countries of the European Community [EC] are...presented. First of all the aims and contents of population projections are discussed. Secondly the methods and assumptions of different population projections for the countries of the EC are compared. Finally the results of such projections are shown and discussed."

European Union↗
PubMed1983

A multiregional population-projection framework that incorporates both migration and residential mobility streams: application to metropolitan city-suburb redistribution.

"In this paper the author introduces a population-projection framework that incorporates interregional migration and intraregional residential mobility streams to project future population sizes both across and within regions in a manner that is consistent with existing migration theory. The author presents a general matrix model of the framework, shows how its parameters can be estimated from fixed-interval census migration data, and discusses how the framework can be employed to 'update' population projections when recent, more limited data sets become available. These features of the framework are demonstrated with intrametropolitan central-city-suburb projections for selected US Standard Metropolitan Statistical Areas over the period, 1970-2020."

Americas↗
PubMed1988

Comparison of microcomputer programs for making population projections: an update.

"There are many programs for making population projections now available for use with microcomputers. This article reviews six of approximately 15 microcomputer population projection programs. Each program is compared to a standard set of criteria relating to such items as hardware and software requirements, input data requirements and specification of assumptions, methodology and documentation, and summary output indicators. Numerical results from projections of six test data sets reflecting different assumptions about mortality, fertility, and migration are compared. Qualitative comments are included for describing special features and for making an overall assessment of each program." (SUMMARY IN FRE)

Computers↗
PubMed1987

A stochastic population projection system based on general age-dependent branching processes.

"Algorithms for a stochastic population process, based on assumptions underlying general age-dependent branching processes in discrete time with time inhomogeneous laws of evolution, are developed through the use of a new representation of basic random functions involving birth cohorts and random sums of random variables. New algorithms provide a capability for computing the mean age structure of the process as well as variances and covariances, measuring variation about means. Four exploratory population projections, testing the implications of the algorithms for the case of time-homogeneous laws of evolution, are presented. Formulas extending mean and variance functions for unit population projections...are also presented. These formulas show that, in population processes with non-random laws of evolution, stochastic fluctuations about the mean function are negligible when initial population size is large. Further extensions of these formulas to the case of randomized laws of evolution suggest that stochastic fluctuations about the mean function can be significant even for large initial populations."

Age Factors↗
PubMed1989

Detailed population projections for small areas: the Massachusetts experience.

There is an urgent and growing need for population projections that are not only detailed by geographic unit, but are also detailed by demographic characteristics. A high level of disaggregation allows the planner considerable flexibility to aggregate the projected data in a variety of geographic and demographic configurations. This study reports on the methodology and results of the Massachusetts experience in developing detailed population projections. Combining conventional with some not-so-conventional techniques, population projections are developed for 351 geographic units, as well as 108 demographic categories. The projections are currently in use in a large variety of public and private planning activities.

Catchment Area, Health↗