Demography and public health

The health and healthcare needs of a population cannot be measured or met without knowledge of its size and characteristics. Demography is the scientific study of population and is concerned both with the measurement, or estimation, of population size and structure and with population dynamics—the interplay between fertility, mortality, and migration which determines population change. These are pre-requisites for making the forecasts about future population size and structure which largely determine the health profile of a population and should underpin public health planning. This chapter presents information on demographic methods and data sources, their application to health and population issues, information on demographic trends and their implications, and the major theories about demographic change. The aim is to illustrate and elucidate the complex inter-relationship between population change and human health.

Applying Concepts and Tools in Demography for Estimating, Analyzing, and Forecasting Forced Migration

Among demographic events (birth, death, and migration), migration is notably the most volatile component to forecast accurately. Accounting for forced migration is even more challenging given the difficulty in collecting forced migration data. Knowledge of trends and patterns of forced migration and its future trajectory is, however, highly relevant for policy planning for migrant sending and receiving areas. This paper aims to review existing methodological tools to estimate and forecast migration in demography and explore how they can be applied to the study of forced migration. It presents steps towards estimation of forced migration and future assessments, which comprise: (1) migration flows estimation methods using both traditional and nontraditional data; (2) empirical analysis of drivers of migration and migration patterns; and (3) forecasting migration based on multidimensional population projections and scenarios approach. The paper then discusses how these demographic methods and tools can be applied to estimate and forecast forced migration.

Spatial demography

Demographic methods can be used to study the spatial response of individuals and populations to current global changes. The first mechanism underlying range shifts is a change in the spatial distribution of births and deaths. The spatial regression of demographic rates with geostatistical and spatially explicit models documents the intrinsic growth rate across the range of a population. The population distribution is expected to shift towards areas with the largest intrinsic growth rate, both mechanistically and because these areas are attractive to dispersing individuals. The second mechanism is indeed movement, including emigration away from places that recently became inhospitable and immigration into newly available locations. The analysis of dispersal fluxes using movement data, or indirectly by comparing the observed and intrinsic growth rates in integrated population models, documents these fluxes. Combining these two mechanisms in integral projection models or in individual-based simulations is expected to yield major advances in predictive spatial ecology, that is, mechanistic species distribution models.

Demographic methods in epidemiology

Demography is both shaped by and shapes infectious disease dynamics. Infectious pathogens can increase host mortality. Host birth rates introduce new susceptible individuals into the population, which allows infections to persist in the face of the depletion of susceptible individuals that can result from mortality or immunity that can follow infection. Many important processes in infectious disease epidemiology, from transmission to vaccination, vary as a function of age or life stage. Epidemiology thus requires demographic methods. This chapter introduces broad expectations for patterns emerging from the intersection between demography and epidemiology and presents a set of structured population modelling tools that can be used to dissect important processes, including next generation methods, and estimation of R0 in the context of stage structure and with important differences in time-scale between host demography and pathogen life cycle.

Demographic Methods across the Tree of Life

Demography is everywhere in our lives: from birth to death. Demography shapes our daily decisions, as well as the decisions that others make on us (e.g. bank loans, retirement age). Demography is everywhere across the Tree of Life. The universal currencies of demography—survival, development, reproduction, and recruitment—shape the performance of all species, from lions to dandelions. The omnipresence of demography in all things alive and dead, and its multiple applications to better understand the ecology, evolution, and conservation/management of species, allows us to—in principle—apply the wide array of quantitative methods to, for example, bacteria or humans. However, demographic methods to date have remained taxonomically siloed, despite the fact that, to a large extent, they are widely applicable across the Tree of Life. In this book, we walk nonexperts through the ABCs of data collection, model construction, analyses, and interpretation across a wide repertoire of demographic artillery. This book introduces the reader to some of the demographic methods, including abundance-based models, life tables, matrix population models, integral projection models, integrated population models, and individual based models, to mention a few. Through the careful integration of data collection methods, analytical approaches, and applications, clearly guided through fully reproducible R scripts, we provide a state-of-the-art thorough representation of many of the most popular tools that any demographer (or demographically inclined mind) should equip themselves with.

The Construction, Description, and Analysis of Age-Specific Life-Tables

Methods for constructing a life-table and budget for a species are described, and the various methods for the analysis of stage-frequency data reviewed. Stage-frequency data comprise counts of the individuals in different development stages in samples taken from a population over a period of time. The analysis of stage-frequency data to estimate the durations of the stages, the numbers entering stages, and survival rates is described. Examples of survivorship curves are presented, and the calculation of population growth rate described. Analysis of life-table data and demographic methods, including key-factor analysis, are described.

Exploring the Social Security Benefit Implications of Same-Sex Marriage

Same-sex marriage became legal nationwide in the United States on June 26, 2015. Federal legalization of same sex marriage expands the pool of individuals potentially eligible for spousal benefits from Social Security to the estimated 4% of the population that is lesbian, gay, or bisexual. This chapter is a foundational step to better understand the potential impact of the expansion of marriage rights to same-sex couples on Social Security. We primarily use data from the 2011-2015 American Community Survey to describe the economic circumstances of heterosexual and same-sex households. We estimate the anticipated social security benefit amounts for these individuals, as well as eligibility to claim spousal benefits. We estimate the size of the gay and lesbian populations by age and sex from 2017-2040 using standard demographic methods. Finally, we supplement the analyses with new data from the RAND American Life Panel.

Mapping Empire: Knowledge Production and Government in the Nineteenth-Century Ottoman Empire

Many studies of the nineteenth century Middle East and North Africa (MENA) region have been concerned with the economic, social and political influence exerted by European colonial governments through the accumulation of knowledge about the region and its subsequent military domination. The case of the Ottoman Empire in the nineteenth century demonstrates that European techniques of knowledge production were also strategically adopted by ruling elites outside the colonial metropolises. Ottoman adoption of European technologies and techniques were politically entwined with the empire’s territorial claims against nascent nationalisms and a calculated move towards knowledge-based forms of government administration in the quest to hold onto power. Cartographic and demographic methods used by the Ottomans produced new assemblages of territory and population that profoundly reshaped the objective of government and the conduct of imperial administration. Statistics and geography became the choice tools of social progress and advancement, underpinning the numerous reforms of the nineteenth century aimed at rationalisation and centralisation.