Table of Contents

Introduction

Fertility

Mortality

Migration

Population Size and Growth

Population Composition

Population Distribution

Population Growth Issues

Concern About Population

Conclusion

Suggested Resources

References

Related Publications

By Joseph A. McFalls, Jr.

This Population Bulletin, published in September 1998, presents the basic what, why, and how of the study of demography. This bulletin discusses the basic forces of demographic change — fertility, mortality, and migration — and common assessment measures. It also introduces major population-related issues such as environmental degradation and poverty in the developing world. 

Order the complete 44-page bulletin.

View a list of related publications.

Introduction

Most people think demography is just math in disguise—a sort of dry social accounting. Once exposed to the subject, many change their minds. They come to appreciate the profound impact demographic forces have on societies. This has never been more true than during the past half-century, a period in which the United States and other societies have experienced unprecedented social and demographic change. Since these demographic forces have not been stilled, they will continue to cause social change and to shape social programs for the balance of our lives and beyond.

People also find demography fascinating because it deals with so many personally relevant topics. Nearly all the major events of people's lives have demographic implications: birth, schooling, marriage, choosing an occupation, childbearing, retirement, and death. Consider the following questions:

 
• When and where were you born? How many others were born the same year? 
• What is your probability of getting married or divorced? 
• Do you have children or do you ever plan to? How many, and how far apart? 
• What kind of job will you have? How often will you change jobs? What are your chances of promotion? When will you retire? 
• How many times will you move? Will you move around the block or overseas? 
• How long will you live? What are the chances of your dying within a year? Within 10 years? What is likely to kill you? 

Demography, or population studies, is a discipline, an "interdiscipline," and a subdiscipline. It is clearly a discipline because it is a field with its own body of interrelated concepts, techniques, journals, departments, and professional associations. Demography is also an interdisciplinary field because it draws its subject matter and methods from many disciplines, including sociology, economics, biology, geography, history, and the health sciences. Finally, demography is also considered a subdiscipline within some of these same major disciplines. In most universities, demography courses are taught within the sociology curriculum, perhaps because population phenomena have so long been linked to social processes.¹

Demography is defined as the study of human populations: their size, composition, and distribution, as well as the causes and consequences of changes in these characteristics. Populations are never static. They grow or decline through the interplay of three demographic processes: birth, death, and migration. If some groups within a population grow or decline faster than others, the composition of the whole is altered.

This Population Bulletin presents the basic what, why, and how of the study of demography. It is not a comprehensive treatment of the subject, but it does provide an overview of demographic processes and the basic measures used to assess them. In addition, it traces population trends in the world and the United States, surveys the demographic differences among population groups, and examines broad social issues linked to population change.

The first three sections of this Bulletin provide the framework for studying the dynamics of population. Fertility, mortality, and migration are at the root of all demographic change. The fourth section reveals how changes in fertility, mortality, and migration affect a population's size and growth rate, and how population projections are calculated. The fifth section delves into the composition of populations according to common variables: age, sex, and race or ethnicity. The sixth section describes how the geographic distribution of populations changes, primarily through migration. The final sections discuss issues and problems associated with population growth.