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At least 883 records · Page 49Linked to original sources
PubMed1992

How reporting delay, duration of follow-up and number of cases affect the estimates of the incubation time of transfusion-associated AIDS cases.

The authors discuss the impact of reporting delay, duration of follow-up, and number of cases in a sample on estimates of the incubation time of transfusion-associated AIDS cases. "This article comes to the conclusion that the accuracy of the incubation time estimate would depend on the sample size rather than on the duration of follow-up." (SUMMARY IN FRE)

Acquired Immunodeficiency Syndrome↗
PubMed1992

Empirical methods for the estimation of the mixing probabilities for socially structured populations from a single survey sample.

"The role of variability of sexual behavior in the transmission dynamics of HIV and AIDS has been illustrated, through the use of mathematical models, by several investigators.... In this paper we describe some practical methods for estimating the deviations from random mixing from a single survey sample.... We include a description of the role of the estimated mixing probabilities in models for the spread of HIV, a discussion of alternatives and possible extensions of the methods described in this article, and an outline of future directions of research." (SUMMARY IN FRE)

Acquired Immunodeficiency Syndrome↗
PubMed1992

Optimal estimate of population age structure with varying vital rates.

The author presents a method for estimating the age distribution of a population under varying vital statistics. "Some mathematical aspects of the method, as well as its applicability, will be discussed and numerical simulation will be run to illustrate the results and to compare the method with the traditional estimate of stable population theory...."

Age Distribution↗
PubMed1993

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↗
PubMed1994

A consistency algorithm based on information theory.

"This paper provides a geometric-mean solution to the consistency problem of multidimensional demographic projection models, based on the constrained minimization of an entropy function. A comparison with the existing harmonic-mean solution yields many similarities and almost no differences....However, one major advantage of the geometric mean is that its corresponding distance function is firmly based on (information) theory." (SUMMARY IN FRE)

Evaluation Studies as Topic↗
PubMed1994

Count data models for demographic data.

"This paper deals with the estimation of single equation models in which the counts are regressed on a set of observed individual characteristics such as age, gender, or nationality.... We propose a generalized event count model to simultaneously allow for a wide class of count data models and account for over- and underdispersion. This model is successfully applied to German data on fertility, divorces and mobility." (SUMMARY IN FRE)

Demography↗
PubMed1995

Population forecasting: do simple models outperform complex models?

"This paper reviews the growing literature on population forecasting to examine a curious paradox: despite continuing refinements in the specification of models used to represent population dynamics, simple exponential growth models, it is claimed, continue to outperform such more complex models in forecasting exercises. Shrinking a large complex model in order to simplify it typically involves two processes: aggregation and decomposition. Both processes are known to introduce biases into the resulting representations of population dynamics. Thus it is difficult to accept the conclusion that simple models outperform complex models. Moreover, assessments of forecasting performance are notoriously difficult to carry out, because they inevitably depend not only on the models used but also on the particular historical periods selected for examination.... This paper reviews some of the recent debate on the simple versus complex modeling issue and links it to the questions of model bias and distributional momentum impacts." (SUMMARY IN FRE)

Demography↗
PubMed1995

Disaggregation in population forecasting: do we need it? And how to do it simply.

"We have described a method for reducing the dimensionality of the forecasting problem by parsimoniously modeling the evolution over time of the age schedules of vital rates. This method steers a middle course between forecasting aggregates and forecasting individual age specific rates: we reduce the problem to forecasting a single parameter for fertility and another one for mortality. We have described a number of refinements and extensions of those basic methods, which preserve their underlying structure and simplicity. In particular, we show how one can fit the model more simply, incorporate lower bounds to the forecasts of rates, disaggregate by sex or race, and prepare integrated forecasts of rates for a collection of regions. We also discuss alternate approaches to forecasting the estimated indices of fertility and mortality, including state-space methods. These many versions of the basic method have yielded remarkably similar results." (SUMMARY IN FRE)

Age Distribution↗
PubMed1995

Simple versus complex models: evaluation, accuracy, and combining.

"This paper argues that it is premature to decide whether simple forecasting models in demography are more (or less) accurate than complex models and whether causal models are more (or less) accurate than noncausal models. It is also too early to say under what conditions one type of model can outperform another. The paper also questions the wisdom of searching for a single best model or approach. It suggests that combining forecasts may improve accuracy." (SUMMARY IN FRE)

Evaluation Studies as Topic↗
PubMed1995

Are mortality projections always more pessimistic when disaggregated by cause of death?

"It is often observed that mortality projections are more pessimistic when disaggregated by cause of death. This article explores the generality and strength of this relationship under a variety of forecasting models. First, a simple measure of the pessimism inherent in cause-based mortality forecasts is derived. Second, it is shown that the pessimism of cause-based forecasts can be approximated using only data on the distribution of deaths by cause in two pervious time periods. Third, using Japanese mortality data during 1951-1990, the analysis demonstrates that the pessimism of cause-based forecasts can be attributed mainly to observed trends in mortality due to cancer and heart disease, with smaller contribution due to trends in stroke (women only), pneumonia/bronchitis, accidents, and suicide. The last point requires the important qualification, however, that observed trends in cancer and heart disease may be severely biased due to changes in diagnostic practice." (SUMMARY IN FRE)

Asia↗
PubMed1996

Population growth under changed fertility schedule in stability conditions.

"This paper aims to investigate some models for population projection under a gradual change in fertility schedule, and to evaluate integrals therein for their actual values.... Some formulae for population projection have been derived under stability conditions. The proposed formulae are also illustrated with some numerical values of the parameters involved therein. The merits and shortcomings are also discussed." (SUMMARY IN FRE)

Demography↗
PubMed1997

A multi-dimensional model for projecting family households--with an illustrative numerical application.

"This paper develops a multi-dimensional model for projecting households and population. The model is constructed to ensure consistency between the demographic events occurring to males and females as well as to parents and children. The model permits projection of characteristics of households, their members, and population structure, using data that are usually available from conventional sources. Unlike the traditional headship-rate method, our model can closely link the projected households with demographic rates. The model includes both nuclear and three-generation households, so that it can be used for countries where nuclear households are dominant and for countries where nuclear and three-generation households are both important. The illustrative application to China, although brief, provides some policy-relevant information about future trends of Chinese household size, structure, and the age and sex distribution of the population, with a focus on the elderly."

Age Distribution↗
PubMed1997

Modelling regional population growth in China.

"This paper develops a forward demographic rates-based multiregional population model on the basis of a set of multiregional population accounts. Forward emigration rates and immigration flows are adopted to describe the external migrations. The model is used to make consistent multiregional population projections of China at a provincial level.... Three sets of multiregional population projections of China at provincial level are made for the period 1987-2087. It is found that the national population trend is a combination of various regional population trends. Some regions, such as Zhejiang, will reach their population peak as early as the beginning of the next century while other regions, such as Xinjiang, will face continuous population growth in the first half of the next century."

Asia↗
PubMed1980

Future changes in the size and composition of the British labour force: a regional projection exercise.

"The main purpose of this study is to develop a methodology for generating parallel projections of regional population and labour force which not only incorporates expected age/sex/marital-status/regional differences in the economic activity rates but at the same time takes account of demographic factors such as fertility, mortality and interregional migration in the overall projections." A model is developed and adapted to project the British regional population and labor force for 1976 and 1981. These forecasts are then evaluated by comparing them with Office of Population Censuses and Surveys forecasts for the same years (SUMMARY IN FRE, GER)

Developed Countries↗