Official Population Projections Research Articles

BayesPop: Probabilistic Population Projections.

We describe bayesPop, an R package for producing probabilistic population projections for all countries. This uses probabilistic projections of total fertility and life expectancy generated by Bayesian hierarchical models. It produces a sample from the joint posterior predictive distribution of future age- and sex-specific population counts, fertility rates and mortality rates, as well as future numbers of births and deaths. It provides graphical ways of summarizing this information, including trajectory plots and various kinds of probabilistic population pyramids. An expression language is introduced which allows the user to produce the predictive distribution of a wide variety of derived population quantities, such as the median age or the old age dependency ratio. The package produces aggregated projections for sets of countries, such as UN regions or trading blocs. The methodology has been used by the United Nations to produce their most recent official population projections for all countries, published in the World Population Prospects.

Forecasting Immigration in Official Population Projections Using an Econometric Model

Although substantial research has been conducted to quantify the determinants of international migration, most official population projections do not include such determinants in a formal migration model. Statistics Norway forecasts gross immigration to Norway using an econometric model based on standard migration theories. The main variables include income level, unemployment, and population size in Norway and the sending countries, and the number of immigrants already living in Norway. Projections of exogenous variables are drawn from international and Norwegian sources. Three different alternatives are specified for the income variables, leading to three different forecasts for gross immigration until 2100.

Treatment Options for Age-Related Macular Degeneration: A Budget Impact Analysis from the Perspective of the Brazilian Public Health System.

BackgroundAge-related macular degeneration (AMD) is a disease that causes reduced visual acuity and blindness. The new treatment options for AMD are not provided by the Brazilian public health system.ObjectiveTo conduct a budget impact analysis of three scenarios for the introduction of AMD treatments: all the medications (verteporfin, ranibizumab, and bevacizumab–the reference scenario), ranibizumab alone, and bevacizumab alone.MethodsThe basic assumption was that the Brazilian public health system would treat the entire target population with AMD aged > 70 years between 2008 and 2011. The size of the population of interest was estimated from official population projections and the prevalence of the disease was obtained from a systematic review. Medication prices were estimated by weighting their market values with correction factors to take account of the public procurement policy. The possibility of aliquoting bevacizumab was also considered. A panel of experts was consulted to estimate the market share of the different medications for the reference scenario. The incremental costs of the ranibizumab-alone and bevacizumab-alone scenarios compared to the reference scenario were calculated. Univariate sensitivity analyses were run to check the robustness of the model.ResultsIn four years, the Brazilian public health system would have treated 1,136,349 individuals with AMD. The annual costs of treating one patient would have been US$476.65 for bevacizumab, US$11,469.39 for ranibizumab, and US$4,376.28 for verteporfin. The incremental cost of the ranibizumab-alone scenario would have been US$1,878,318,056.00 in four years, while the incremental cost for the bevacizumab-alone scenario would have been a reduction of US$4,978,326,359.00 (i.e., a cost saving) in the same period. The bevacizumab-alone option was found to represent a cost saving across sensitivity analyses.ConclusionThe introduction of bevacizumab for the treatment of AMD is recommended for the Brazilian Public Health System.

How accurate are official subnational population projections

How accurate are official subnational population projections

Population Aging in Postwar Japan: Processes and Prospects

This paper critically reviews postwar population development in Japan and aims to identify unsolved issues, which are possibly shared by other countries, and extract lessons for the future. First, I examine long-term development on fertility and life expectancy in Japan with a brief introduction of pre-war population history. I stress that some critical issues have often been ignored in policy debates and some important new challenges are now emerging, factors that are indispensable to extract lessons for the future. Second, I turn to the official population projections and related issues which again require scrutiny. Third, I emphasize that serious scientific investigation from multiple disciplines is essential to cope with the challenges of demographic changes and that Japan should take the leading role in research for the next generations all over the world.

Population Projections and Demographic Knowledge in France and Great Britain in the Postwar Period

This study examines how official national population projections—a key mechanism for the production and dissemination of demographic knowledge—contributed to differing interpretations of population and fertility trends in France and Great Britain in the decades following World War II, despite these countries' similar fertility rates during most of this period. Projections presented different visions of the demographic future in the two countries. In France, publication of multiple variants emphasized future contingency, with low variants illustrating future population decline due to prolonged below-replacement fertility. In Britain, publication of a single variant, assuming near-replacement-level fertility rates, projected moderate growth. National population projections thus created divergent representations of the two countries' demographic futures: an ever-present threat of population decline in France, and a reassuring image of stability in Britain. Two principal mechanisms that contributed to cross-national differences in population projections—national demographic history and institutional configurations—are discussed.

Envelhecimento populacional, gratuidades no transporte público e seus efeitos sobre as tarifas na Região Metropolitana de São Paulo

In Brazil, students, children under four years of age and people aged 65 and over are entitled to partial or full concessions on urban travel in public transport systems. These discounts are not covered by public funding, but rather via cross-subsidization charged to the other service users who pay the full fare. In this study, the effects of population aging on public transport fares for the next four decades in the metropolitan region of Sao Paulo (MRSP), the largest metropolitan area in Brazil, are estimated. The analyses in this paper are based on data from the Pesquisa Origem-Destino (Origin-Destination Survey), carried out in 2007 in the MRSP, and on official population projections developed by IBGE (the Brazilian Institute of Geography and Statistics) and Fundacao Seade (the Seade Foundation) for the years 2020, 2030 and 2050. Considering the different periods of population projection, the technique of direct standardization to simulate expected changes in the composition of public transport trips was utilized, in terms of paying and non-paying passengers. The results indicate that, in the short term (2020), population aging expected to occur in the MRSP should have a modest effect on the total number and age composition of public transport trips in the region. However, if the current cross-subsidization mechanism is maintained, the expected growth in the percentage of non-paying passengers could result in an increase in fares by about 10% and 20% in the medium and long terms. DOI http://dx.doi.org/10.1590/S0102-30982015000000006

Predicting Future Blood Demand from Thalassemia Major Patients in Hong Kong

BackgroundIn Hong Kong, thalassemia major (TM) patients utilized up to 9.5% of blood supply in 2009. For long-term management of blood supply, we predicted the future blood demand of TM patients for the next 10 years.Methods and ResultsAnnual individual transfusion data in 2005–2009 and demographic information of 381 TM patients were obtained from the Hong Kong Red Cross Blood Transfusion Service database. A generalized estimating equation (GEE) model was fitted to establish the potential relations of blood demand with age, sex, body weight, year of transfusion and splenectomy, accounted for within-patient correlation. The fitted model was used to predict future blood demand for the existing patients by accounting for expected change in body weight and mortality rate. We also predicted the number of new cases in the future based on age- and sex-specific TM incidence and official population projections. Future blood demand was predicted by combining blood demand from the existing and new patients. Female (RR = 0.94, p = 0.006) and history of splenectomy (RR = 0.85, p<0.001) were significantly associated with lower blood demand, while age and weight had an inverted U-shape relation with maximal blood demand at around 24 years of age and 71.8 kg, respectively. We predicted that the total blood demand would increase 0.81% annually from 13,459 units in 2009 to 15,183 units in 2024, with new TM cases accounting for 31.7% of the overall blood demand in 2024.ConclusionsOur results showed that future annual blood demand from TM patients would steadily increase in the next 10 years. Reducing incidence of TM cases in the future (by improving public education, antenatal care, prenatal diagnosis) and minimizing blood use among existing TM cases (e.g. with hemopoietic stem cell transplantation) can help relieve the burden on management of future blood demand.

Age- and time-dependent model of the prevalence of non-communicable diseases and application to dementia in Germany

We derive a partial differential equation (PDE) that models the age-specific prevalence of a disease as a function of the incidence, remission and mortality rates. The main focus is on non-communicable diseases (NCDs), although the PDE is not restricted to NCDs. As an application of the PDE, the number of persons with dementia in Germany until the year 2050 is estimated based on German incidence data and official population projections. Uncertainty is treated by different scenarios about life expectancy, number of migrants, prevalence of the disease in migrants, and scenarios about the future incidence, and mortality of demented persons. Life expectancy and incidence of dementia have the strongest impact on the future number of persons with dementia. In nearly all scenarios, our estimated case numbers exceed former estimates. Furthermore, we use an example to show that the PDE method yields more accurate results than a common alternative approach.

Estimates of Indonesian population numbers: first impressions from the 2010 census

This note provides a critical perspective on the preliminary results of the 2010 population census, which were announced by President Yudhoyono on 16 August 2010. It explores the concepts of population used and the adjustments made to increase the accuracy of census estimates. The assumptions underlying various official population projections in the last decade produced estimates for mid-2010 that were substantially below the figure of over 237 million persons counted in May. The note argues that, far from reflecting a ‘population explosion’, this is due to the achievement in the 2010 census of greatly increased coverage of people residing in Indonesia on the census date.

A comparison of official population projections with Bayesian time series forecasts for England and Wales

We compare official population projections with Bayesian time series forecasts for England and Wales. The Bayesian approach allows the integration of uncertainty in the data, models and model parameters in a coherent and consistent manner. Bayesian methodology for time-series forecasting is introduced, including autoregressive (AR) and stochastic volatility (SV) models. These models are then fitted to a historical time series of data from 1841 to 2007 and used to predict future population totals to 2033. These results are compared to the most recent projections produced by the Office for National Statistics. Sensitivity analyses are then performed to test the effect of changes in the prior uncertainty for a single parameter. Finally, in-sample forecasts are compared with actual population and previous official projections. The article ends with some conclusions and recommendations for future work.

Persistence and change of the relative difference in educational attainment by ethno-cultural group and gender in Canada

This article presents analytical findings on the persistence and change of the relative difference in educational attainment by ethno-cultural group and gender in Canada. As these trends cannot be observed from a single data source, a modelling technique to integrate longitudinal data lacking ethno-cultural detail with cross-sectional Census data was developed. First- and second-generation immigrants and/or members of most visible minority groups on average reach higher educational levels than their Canadian-born peers not belonging to a visible minority. This study reveals that the relative educational differences between the studied groups are both important in extent and remarkably stable over birth cohorts. The research presented in this paper was conducted in the context of Statistics Canada&#x2019;s population projection microsimulation model Demosim. Demosim marks an important milestone in establishing microsimulation for official population projections. It reflects the demand for models which can go beyond age and sex, capturing geographical detail, ethnic diversity, educational attainment and other characteristics.

Population ageing in Sweden: the effect of change in educational composition on the future number of older people suffering severe ill-health.

We investigate how expected changes in the educational level composition of the older population may affect future prevalence of severe ill-health among older people in Sweden. Previous research has indicated that the number of older people, given educational differentials in mortality and expected changes in educational composition during the next decades, may increase more than expected following official population projections in Sweden. Eight alternative scenario projections for the possible development in the number of people with severe ill-health in Sweden between 2000 and 2035 are presented. Scenario projections, where both morbidity and mortality inequalities by educational level are taken into account, are compared with scenarios in which only age and gender are modelled. The projections are made with both constant and decreasing mortality. The calculations show that the expected increases in severe ill-health as a result from the ageing of the population in the period 2000-2035 might, to a large extent, be counteracted by the increase in the educational level of the Swedish population. We recommend therefore that in projections of the prevalence of ill-health, in addition to the ageing of the population, also changes in educational level should be taken into account.

Stochastic population forecast for Germany and its consequence for the German pension system

Population forecasts are crucial for many social, political and economic decisions. Official population projections rely in general on deterministic models which use different scenarios for future vital rates to indicate uncertainty. However, this technique shows substantial weak points such as assuming absolute correlations between the demographic components. In this paper, we argue that a stochastic projection alternative, with no a priori assumptions provides point forecasts and probabilistic prediction intervals for demographic parameters in addition. Age-sex specific population forecast for Germany is derived through a stochastic population renewal process using forecasts of mortality, fertility and migration. Time series models with demographic restrictions are used to describe immigration, emigration and time varying indices of mortality and fertility rates. These models are then used in the simulation of future vital rates to obtain age-specific population forecast using the cohort-component method. The consequence for the German pension system is discussed. To maintain the actual average pension level the premium rate of the present system rises at least by 50% as the old-age ratio nearly doubles by 2040.

The ‘Golden Generations’ in Historical Context

ABSTRACTAssumptions about future mortality are more important than those for factors such as fertility, migration, disability trends or real interest rates for cost projections of the U.S. Old Age, Survivors, Disability and Health Insurance scheme. Recently, one factor has been assumed to be the key driver of future mortality in both official British population projections and actuarial ones: a ‘cohort effect’ associated with a group who were born in a period centred on the early 1930s who have been identified as having experienced particularly rapid improvements in mortality rates and are often referred to as the ‘golden generations’ or ‘golden cohorts’. The concept of ‘cohort effects’ is discussed; limitations of national-level cohort data considered; and methods for identifying such effects are reviewed. Particular attention is given to the analysis of populations which have been identified as having clear cut cohort effects; those of Britain and Sweden in the later part of the nineteenth century and early twentieth century, as well as the contemporary British population. The likely magnitude of such effects is discussed using a stylised model to assess the extent to which members of the ‘golden generations’ are especially privileged.

The future burden of cancer in England: incidence and numbers of new patients in 2020

We estimated the future cancer incidence rates and the future numbers of cancer cases in England up to 2020 using cancer registration data for 1974–2003, and the official population projections from ONS up to 2023. Data were analysed using an age-period-cohort model as developed for the Nordic countries. We predict that for all cancers combined there will be relatively little change in age-standardised incidence rates in 2020. The number of new cancer cases per year in England is, however, predicted to increase by 33%, from 224 000 in 2001 to 299 000 cases in 2020. This increase is mainly due to the anticipated effects of population growth and ageing; cancer patients in 2020 will be older than today's cancer population.

Australia's uncertain demographic future

The techniques of probabilistic population forecasting are increasingly being recognised as a profitable means of overcoming many of the limitations of conventional deterministic variant population forecasts. This paper applies these techniques to present the first comprehensive set of probabilistic population forecasts for Australia. We stress the disadvantages of directly inputting net migration into the cohort component model in probabilistic forecasting, and propose a gross migration flows model which distinguishes between permanent and non-permanent immigration and emigration. Our forecasts suggest that there is a two thirds probability of Australia's population being between 23.0 and 25.8 million by 2026 and between 24.4 and 31.8 million by 2051. Comparisons with the latest official population projections of the Australian Bureau of Statistics are made.

Projecting Mortality Trends

The sustained reduction in mortality rates and its systematic underestimation has been attracting the significant interest of researchers in recent times because of its potential impact on population size and structure, social security systems, and (from an actuarial perspective) the life insurance and pensions industry worldwide. Despite the number of papers published in recent years, a comprehensive review has not yet been developed. This paper attempts to be the starting point for that review, highlighting the importance of recently published research—most of the references cited span the last 10 years—and covering the main methodologies that have been applied to the projection of mortality rates in the United Kingdom and the United States. A comparative review of techniques used in official population projections, actuarial applications, and the most influential scientific approaches is provided. In the course of the review an attempt is made to identify common themes and similarities in methods and results. In both official projections and actuarial applications there is some evidence of systematic overestimation of mortality rates. Models developed by academic researchers seem to reveal a trade-off between the plausibility of the projected age pattern and the ease of measuring the uncertainty involved. The Lee-Carter model is one approach that appears to solve this apparent dilemma. There is a broad consensus across the resulting projections: (1) an approximately log-linear relationship between mortality rates and time, (2) decreasing improvements according to age, and (3) an increasing trend in the relative rate of mortality change over age. In addition, evidence suggests that excessive reliance on expert opinion—present to some extent in all methods—has led to systematic underestimation of mortality improvements.

The projected increase in glaucoma due to an ageing population.

The number of cases of primary open angle glaucoma (POAG) in England and Wales is estimated to increase by a third over the 20 years to 2021, and then continue upwards at a similar pace to 2031. The estimates are based on official population projections, organised by 5-year age groups, together with an age-specific prevalence curve for POAG derived from the results of 11 epidemiological prevalence surveys. To cope with additional pressures, a thorough reappraisal of the present system for detection, referral, diagnosis, treatment and monitoring of the disease is likely to be required.

Domestic Water Demand Forecasting: A Static Microsimulation Approach

AbstractPlanning the provision of a future water supply depends upon forecasts of likely demand. Existing forecasting techniques suffer from a lack of spatially relevant information on likely trends in the micro‐components of demand. At a sub‐regional level, current approaches also understate between‐area variability. A static micro‐simulation model is described, which makes more efficient use of existing data in producing forecasts of domestic water consumption. Spatially detailed synthetic microdata are reweighted towards level population estimates which are derived from official Government population projections. A 30% increase in domestic consumption between 1991 and 2025 is forecast for the Yorkshire Water region, three‐quarters of which is attributable to changes in consumer behaviour.