Realistic Demography Research Articles

Assessing the generational impact of COVID-19 using National Transfer Accounts (NTAs)

An important aspect of the current COVID-19 crisis is that not all age groups are equally affected by the pandemic. To account for the generational impact of COVID- 19, a dynamic overlapping generations model with realistic demography, human capital and NTAs is constructed. The COVID-19 crisis is modelled through two unexpected and temporary negative shocks: an economic shock that reduces labour income, and a demographic shock that increases the mortality hazard rates of those infected. The model is applied to 12 countries for which full NTA data are available. Results are presented for two extreme fiscal policies: one in which governments compensate workers for 0% (without fiscal support) of their total labour income losses due to the pandemic, and another in which governments compensate workers for 100% (with fiscal support) of these losses. In addition, I analyse the impact of these policies on public debt. The results show that COVID-19 is affecting the financial situations of people aged 25 to 64 and their children more than those of older people. By compensating workers for their income losses, the economic impact of COVID-19 has been more evenly distributed across cohorts, reducing the burden on people aged zero to 64, and increasing the burden on people aged 65 and older. Moreover, the simulation results show that a 1% decline in labour income leads to an average increase in the debt-to-total labour income ratio of between 1.2% (without fiscal policy) and 1.6% (with fiscal policy).

SimBit: A high performance, flexible and easy-to-use population genetic simulator.

SimBit is a general purpose, high performance forward-in-time population genetics simulator. SimBit can simulate a wide variety of selection scenarios (any selection and dominance coefficients variation, any epistatic interaction, any spatial and temporal changes of selection scenario, etc.), demographic scenarios (any changes in patch sizes, migration rates, realistic demography dependent on fecundity, hard vs. soft selection, exponential vs. logistic growth, gametic or zygotic dispersion, etc.) and mating systems (cloning and selfing rates, hermaphrodites or males and females). SimBit can also track QTLs (with hyperdimensional phenotypes, explicit fitness landscape, plasticity, developmental noise, etc.). Finally, SimBit can simulate multiple species with their ecological relationships. SimBit comes with a R wrapper that simplifies the management of an entire research project from the creation of a grid of parameters and corresponding inputs, running simulations and gathering outputs for analysis. SimBit's performance was extensively benchmarked in comparison to SLiM, Nemo and SFS_CODE, varying population size, recombination rate, mutation rate, and the number of loci. I also reproduced simulations from previous studies, benchmarked QTLs and coalescent tree recording techniques. SimBit was most often the highest performing program with the only notable exception of SLiM outperforming SimBit in scenarios with few loci and low genetic diversity.

Medical Care within an OLG Economy with Realistic Demography

We study the role of health care within a continuous time economy of overlapping generations subject to endogenous mortality. The economy consists of two sectors: final goods production and a health care sector, selling medical services to individuals. Individuals demand health care with a view to lowering mortality over their life-cycle. We derive the age-specific individual demand for health care based on the value of life as well as the resulting aggregate demand for health care across the population. We then characterize the general equilibrium allocation of this economy, providing both an analytical and a numerical representation. We study the allocational impact of a medical innovation both in the presence and absence of anticipation; and a temporary baby boom. We place particular emphasis on disentangling general equilibrium from partial equilibrium impacts and identifying the relevant transmission channels.

The Effect of Increasing Human Capital Investment on Economic Growth and Poverty: A Simulation Exercise

This paper examines the dynamic responses of income and poverty to increased investment in the human capital of new cohorts of workers, using a quantitative macroeconomic model with realistic demography. Compared to a baseline in which the rate of human capital investment currently observed in every country remains constant, the paper examines two alternative scenarios: one in which each country experiences a rate of growth of human capital investment that is typical of what was observed in the decade ending in 2015, and one in which each country raises human capital investment at a rate corresponding to the 75th percentile of what was observed in the data. In the former, world GDP per capita is 5 percent higher than baseline in the year 2050, while the global rate of $1.90 poverty is 0.7 percentage points lower in that year. In the latter, world GDP per capita is 12 percent higher than baseline in 2050, while the rate of $1.90 poverty drops by 1.4 percentage points. These gains are concentrated in poor countries. The paper argues in the context of our model that investing in people is more cost effective than investing in physical capital as a means to achieve specified income or poverty goals.

The Effect of Increasing Human Capital Investment on Economic Growth and Poverty: A Simulation Exercise

We examine the dynamic responses of income and poverty to increased investment in the human capital of new cohorts of workers, using a quantitative macroeconomic model with realistic demography. Higher investment leads to significant improvements, although phase-in takes considerable time. Gains are largest in poor countries. We argue in the context of our model that investing in people is more cost effective than investing in physical capital as a means to achieve specified income or poverty goals. We also study the effect of higher human capital on fertility and the follow-on effects of lower fertility on income.

The welfare state and demographic dividends

Background: The demographic transition experienced by developed countries produces initial positive effects on economic growth ‒ the first demographic dividend ‒ which can be extended into a second demographic dividend if baby boomers’ savings increase capital accumulation. Nevertheless, aging might reverse this process if dissaving of elderly baby boomers and the pressure on the pay-as-you-go financed welfare state reduce savings and capital. Objective: The aim of this paper is to evaluate the extent to which demographic dividends in Spain provide an opportunity for the reform of the welfare state system for an aging population. Methods: We decompose demographic dividends using a general equilibrium overlapping generations model with realistic demography and public transfers from the National Transfer Accounts database. This allows us to capture the endogenous evolution of savings and capital accumulation and, hence, the second demographic dividend. Results: When baby boomers enter the labor market, the purely demographic support ratio increases and this positive effect is extended by composition changes in the age structure of workers. When they start saving, the second demographic dividend arises, while its total net effect depends both on the strength of the aging process and on transfer size. Conclusions: The derived decomposition shows that the second demographic dividend might also disappear. Sharp population aging in Spain implies that capital will shrink drastically after 2040. Before this, there seems to be margin for reforms; however, an extension of the welfare state toward the Nordic model would considerably reduce capital. Contribution: This paper contributes to the debate on the effects of demographics on economic growth by decomposing demographic dividends and investigating the impact of different welfare state transfer systems on the second demographic dividend.

Direct and indirect effects of influenza vaccination

BackgroundAfter vaccination, vaccinees acquire some protection against infection and/or disease. Vaccination, therefore, reduces the number of infections in the population. Due to this herd protection, not everybody needs to be vaccinated to prevent infections from spreading.MethodsWe quantify direct and indirect effects of influenza vaccination examining the standard Susceptible-Infected-Recovered (SIR) and Susceptible-Infected-Recovered-Susceptible (SIRS) model as well as simulation results of a sophisticated simulation tool which allows for seasonal transmission of four influenza strains in a population with realistic demography and age-dependent contact patterns.ResultsAs shown analytically for the simple SIR and SIRS transmission models, indirect vaccination effects are bigger than direct ones if the effective reproduction number of disease transmission is close to the critical value of 1. Simulation results for 20–60% vaccination with live influenza vaccine of 2–17 year old children in Germany, averaged over 10 years (2017–26), confirm this result: four to seven times as many influenza cases are prevented among non-vaccinated individuals as among vaccinees. For complications like death due to influenza which occur much more frequently in the unvaccinated elderly than in the vaccination target group of children, indirect benefits can surpass direct ones by a factor of 20 or even more than 30.ConclusionsThe true effect of vaccination can be much bigger than what would be expected by only looking at vaccination coverage and vaccine efficacy.

A 'post-honeymoon' measles epidemic in Burundi: mathematical model-based analysis and implications for vaccination timing.

Using a mathematical model with realistic demography, we analyze a large outbreak of measles in Muyinga sector in rural Burundi in 1988–1989. We generate simulated epidemic curves and age × time epidemic surfaces, which we qualitatively and quantitatively compare with the data. Our findings suggest that supplementary immunization activities (SIAs) should be used in places where routine vaccination cannot keep up with the increasing numbers of susceptible individuals resulting from population growth or from logistical problems such as cold chain maintenance. We use the model to characterize the relationship between SIA frequency and SIA age range necessary to suppress measles outbreaks. If SIAs are less frequent, they must expand their target age range.

Demographic Dividends, Human Capital, and Saving.

Abstract The objective of this paper is to provide new evidence about the development effects of changes in population age structure and human and physical capital. This extends our previous work by developing and employing a more comprehensive model of demographic dividends. In addition, we extend earlier analysis about the quantity-quality tradeoff using newly available NTA data for 39 countries, in contrast to the nineteen with the necessary data in our 2010 study. This permits a more detailed analysis, treating public expenditures and private expenditures separately, and considering the role of per capita income as well as fertility and child dependency in relation to human capital spending. The analysis is used in a simulation with realistic demography to show how human capital investment has varied in relation to the changing demography from 1950 to the present, and how it might be expected to change over the rest of this century. These new estimates are then used in a more comprehensive model that incorporates both human and physical capital. The analysis provides estimates of the first and second demographic dividends and how they are affected by speed of fertility decline. The timing of the effects is documented and the relative importance of investment in physical and human capital is assessed. This improves our understanding of the economic implications of the demographic dividend and particularly the “second demographic dividend”.

The Welfare State and the Demographic Dividend: A Cross-Country Comparison

The sustainability of the welfare state is in doubt in many developed countries due to drastic population ageing. The extent of the problem and the margin for reforms depend - among other factors - on the size of the ageing process and the size of the public transfer system. The latter has a crucial impact on the extent to which the first demographic dividend previous to the ageing process turns into a second demographic dividend. The contribution of the different factors driving the demographic dividend is, ultimately, an empirical question. In this paper we contribute to the debate, exploding the cross-country comparison potentialities of the National Transfer Accounts (NTA) database. In particular, we introduce different configurations of the welfare state transfers - Sweden, United States and Spain - into a realistic demography Overlapping Generations (OLG) model and simulate its effects on the second demographic dividend .

Fertility and mortality changes in an overlapping-generations model with realistic demography

Many overlapping-generations models assume only working and retirement stages and are “not capable of representing the most basic feature of the human economic life cycle: that it begins and ends with periods of dependency, separated by a long intermediate period of consuming less than is produced” (Bommier and Lee, 2003). To examine the economic consequences of fertility and mortality changes in a common framework, we incorporate realistic demographic features into a continuous-time overlapping-generations model with childhood, adulthood and retirement stages. Using parameter values appropriate for industrial countries (such as the USA), we find that a fertility increase and a mortality decline, while both causing a rise in the population growth rate, have opposite effects on capital accumulation. We also consider simultaneous fertility and mortality changes, and find that the effect on capital accumulation of a mortality change dominates that of a fertility change.

Neoclassical growth with endogenous age distribution. Poverty vs low-fertility traps as steady states of demographic transitions

Compared to other factors, the role of the age distribution of the population as a key endogenous determinant of economic growth trajectories has traditionally been overlooked. This is unrealistic, especially when dealing with major epochs of structural change, such as demographic transitions. We set up a model combining a simple representation of the economy, based on the neoclassical growth model of Solow, with a comprehensive representation of population dynamics. The model is used to investigate the structure of balanced growth states of the population and the economy in the presence of demographic transitions. The analysis shows that proper inclusion of age structure enriches the spectrum of the long-run equilibria of the neoclassical model, allowing up to five states of balanced growth, and shows the onset of “poverty” and “low-fertility” traps as different facets of fertility transitions. The role of different timing of fertility, mortality and savings transitions, and of more realistic demography of capital, is also considered.

O1-S09.06 Assessing the impact of a FSW targeted HIV intervention programme on incidence and prevalence in Cotonou, Benin

BackgroundFrom 1993 to 2005 female sex workers (FSW) were the focus of a HIV intervention in Cotonou where most local FSW originated from three neighbouring countries. Intervention impact was assessed...

Demography and Uncertainty in Economic Growth: An Application to Social Security

The aim of this paper is to study the impact on economic growth of public pension systems, both funded and unfunded, under different demographic scenarios with a competitive economy and a fixed labor supply. An OLG growth model is used with realistic demography, in which each individual can be traced throughout her lifecycle, by using a longitudinal accounting framework. Under this setup, I find that both funded and unfunded pension systems can achieve the same steady state, either the «modified golden rule» or the «golden rule,» as long as the population increases. Nonetheless, the dynamic transition of each social security system to this steady state differs. This result shows that when labor supply is inelastic public pension systems do not necessarily alter the capital stock in the long run.

Realistic population dynamics in epidemiological models: the impact of population decline on the dynamics of childhood infectious diseases: Measles in Italy as an example

Most contributions in the field of mathematical modelling of childhood infectious diseases transmission dynamics have focused on stationary or exponentially growing populations. In this paper an epidemiological model with realistic demography is used to investigate the impact of the non-equilibrium conditions typical of the transition to sustained below replacement fertility (BRF) recently observed in a number of western countries, upon the transmission dynamics of measles. The results depend on the manner we model the relation between the (changing) age distribution of the population and contacts. Under some circumstances the transitional ageing phase typical of BRF populations might complexly interact with epidemiological variables leading to (i) a substantial reduction in the amount of vaccination effort required for eliminating the disease; (ii) a significant magnification of the perverse impact of vaccination in terms of the burden of severe age related morbidity.

Ageing populations and childhood infections: the potential impact on epidemic patterns and morbidity.

Population decline, arising from below replacement fertility and possibly giving rise to substantial changes in age distribution, is a feature of many industrialized developed countries; Italy is one of the most notable European examples. The potential influence of this phenomenon on prevalence of chronic non-infectious disease is well known, but little attention to date has been paid to the impact on severe disease due to childhood infections in those cases where control is insufficient to achieve elimination. A transmission dynamics model incorporating realistic demography is used to investigate the possible impact of population decline and ageing and suboptimal vaccination uptake on the age distribution of incidence of measles infection and of consequent mortality. Data from Italy is used to parameterize the model. Population ageing in the absence of vaccination is shown to reduce per capita incidence of infection but also to increase average and upper quartile ages at infection. The effect is substantially enhanced by significantly suboptimal vaccination uptake, when disease-induced mortality has, for a period, the potential to exceed that in the absence of vaccination. Although a substantially increased burden from chronic non-infectious disease has frequently been proposed as a consequence of population decline, there is also potential for an increase in morbidity and mortality from measles and other childhood infectious diseases, particularly where vaccine uptake is substantially below the optimum. Rubella is highlighted as a particular cause for concern. This work also has implications for less-developed countries.

Overlapping generations models with realistic demography

This paper revisits the literature on overlapping generations models in the demographic context of a continuous age distribution and a general age schedule of mortality. We show that most of the static results known for the 3 or N age-group models can be extended to the continuous model. Some results, previously established for economies without capital, are extended to productive economies. We also make some progress on the existence of some steady states as well as on the dynamic properties.

Cost analysis of schistosomiasis

Cost analysis of schistosomiasis is important both in assessing the economic impact of the disease and in identifying the most cost-effective approaches to control. Economic impact has been examined both within and without the health sector, but there is a lack of measurement of the effects of disease, or the threat of disease, on patterns of production and community development. The cost-effectiveness of control approaches has been examined empirically and by using static models. Future analyses require a stronger epidemiological basis incorporating realistic demography and the temporal dynamics of reinfection, and assessment of outcomes in terms of disease rather than infection.