Chapter 3 - Demography and Aging

Abstract

Demography is the study of the size, growth, and characteristics of populations, and aging is a growing area of inquiry within it. Demographers are affiliated with many disciplines and they investigate both individual behaviors and macro phenomena. This chapter focuses on aging at the level of countries, regions, and the world and highlights the unprecedented population aging of recent decades and projected for the future, demographic changes underlying population aging, alternative demographic indicators of aging, demographic consequences of population aging, and policy responses to population aging that are related to demographic factors. Population aging is commonly defined as the growth in the proportion of a population that is above a particular age. Understanding of the population aging process is informed by the stylized facts of the demographic transition and the epidemiologic transition. The influence of migration on the population aging process in a receiving country is more idiosyncratic, depending on immigrants' age distribution and subsequent fertility in comparison to those of the native-born population. A broader characterization of the population aging process is captured by median ages and population pyramids. Demographic phenomena—changes in fertility and mortality—are the driving forces behind population aging, and population aging has important demographic and socioeconomic consequences.