Demography. Uncertain population forecasts.
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Demography↗
Biomedical subjects
N Keilman
Publications and source records attributed to N Keilman.
Predictive intervals for age-specific fertility.
A multivariate ARIMA model is combined with a Gamma curve to predict confidence intervals for age-specific birth rates by 1-year age groups. The method is applied to observed age-specific births in Norway between 1900 and 1995, and predictive intervals are computed for each year up to 2050. The predicted two-thirds confidence intervals for Total Fertility (TF) around 2010 agree well with TF errors in old population forecasts made by Statistics Norway. The method gives useful predictions for age-specific fertility up to the years 2020-30. For later years, the intervals become too wide. Methods that do not take into account estimation errors in the ARIMA model coefficients underestimate the uncertainty for future TF values. The findings suggest that the margin between high and low fertility variants in official population forecasts for many Western countries are too narrow.
Birth Rate↗
Adjustments of public pension schemes in twelve industrialized countries: possible answers to population ageing.
"This article analyses the impact of population dynamics on future public pension expenditure in twelve industrialized countries. Whereas previous studies have mainly emphasized ageing effects, this study looks into the consequences of changing marital status structures as well. Old age pensions, disability, and survivor's pensions are investigated. Various sets of demographic and pension scenarios are formulated for the projections, dealing with changes in demographic, labour force and pension system variables in the future. The analyses show that there can be no adequate demographic response to rising pension costs caused by population ageing at the horizon 2030. Neither an increase in fertility nor an inflow of migrants can rejuvenate national populations, unless fertility and/or migration reach unrealistically high levels. Instead, substantial reductions of the public pension burden have to be sought in socioeconomic measures." (SUMMARY IN FRE)
Demography↗
Sensitivity analysis in a multidimensional demographic projection model with a two-sex algorithm.
"Formulas are derived for the effect that a slight change in the occurrence/exposure rate of the multidimensional projection model has on the elements of the population vector. The projection model classifies the population by sex, age, and marital status. The model includes a two-sex algorithm in order to ensure consistency between numbers of male and female marriages, number of divorces for the two sexes, and new widows (widowers) and deceased spouses. The sensitivity functions and elasticities are applied to data from the Netherlands for the period 1980-1984. The results indicate that marriage market mechanisms, in particular competition and substitution effects, are reasonably well modelled."
Age Distribution↗
The impact of forecasting methodology on the accuracy of national population forecasts: evidence from the Netherlands and Czechoslovakia.
"This study considers the accuracy of national population forecasts of the Netherlands and the Czechoslovak Socialist Republic.... We look at the demographic components employed in each forecast, the procedure to extrapolate fertility and the level at which assumptions for each component are formulated. Errors in total population size, fertility, mortality and foreign migration, and age structure are considered. We discuss trends in errors and methodology since 1950 and compare the situations in the two countries. The findings suggest that methodology has only a very limited impact on the accuracy of national population forecasts."
Czechoslovakia↗
National population forecasts in industrialized countries: main findings of an international workshop.
The main findings are presented from a workshop on national population projections in developed countries, held in Voorburg, Netherlands, October 25-28, 1988. "The programme concentrated on four themes: general aspects of national population projections, fertility, mortality and international migration. Under the first theme, an international comparison of the forecasting process was presented, and items like accuracy, variants and monitoring were discussed. The other sessions contained cross-country overviews of actual trends, most recent assumptions and currently applied extrapolation methods. Furthermore, special attention was given to the use of time series methods and explanatory models for the extrapolation of fertility."
Congresses as Topic↗
Recent trends in family and household composition in Europe.
"This article attempts to give a broad overview of trends in family and household composition in Europe during the last few decades. The focus is on Western Europe. We look at the decreasing average size of the household and the family (section 2) and its demographic causes. The changing role of the traditional family is reviewed in section 3, while section 4 contains a discussion of non-traditional household types: one-parent families, consensual unions and one-person households. Future trends in living arrangements are explored in section 5, where simulation results of a dynamic household model, applied to the Netherlands, are presented." (SUMMARY IN FRE)
Developed Countries↗
Nuptiality models and the two-sex problem in national population forecasts.
"This paper describes the two-sex problem in nuptiality models, focussing on applications in national population forecasts. Requirements for a realistic two-sex marriage model are mentioned, together with additional considerations important in the context of official forecasts. Recent nuptiality models violate the requirements to a certain extent and/or do not meet the additional considerations. A new model, used in the 1980-based population forecasts of the Netherlands compiled by the Netherlands' Central Bureau of Statistics, is described." (summary in FRE)
Demography↗