1. Population Structure and Characteristics
Part Three
Population Structure and Characteristics

2. Part Outline 8 The Age Transition 9 Population Aging
10 The Family and Household Transition
11 The Urban Transition

3. Chapter 8
The Age Transition

4. Chapter Outline The Concepts of Age and Age Cohorts
The Concepts of Sex and Gender
Measuring the Dynamics of the Age Transition
The Age Transition
Age Transitions at Work

5. Age and Age Cohorts
Society assigns social roles on the basis of age and gender.
Younger people are treated differently from older people.
Different kinds of behavior are expected of people as they move through different ages.

6. Age Stratification Theory
Societies distribute resources unequally by age.
These resources include economic goods as well as social approval, acceptance, and respect.
Age strata, and the prestige and power associated with each, are influenced by the needs of society and by characteristics of people at each age.

7. Aspects of Human Society that Vary by Age and Sex
Category
Characteristic or Activity
Demographic
Being sick and having restricted activities
Dying
Being sexually active
Having a baby
Moving or migrating

8. Aspects of Human Society that Vary by Age and Sex
Category
Characteristic or Activity
Social
Getting married/divorced
Being involved in religious organizations and activity
Being involved in political organizations and activity

9. Aspects of Human Society that Vary by Age and Sex
Category
Characteristic or Activity
Social
School enrollment
Level of educational attainment
Being involved in criminal behavior

10. Aspects of Human Society that Vary by Age and Sex
Category
Characteristic or Activity
Economic
Being in the labor force
Occupation within the labor force
Current income
Level of accumulated wealth

11. Lexis Diagram: Relationship between Cohorts and Period Data

12. Age Cohorts and Age Strata Are Closely Intertwined

13. Sex Ratios by Age in Selected Countries, 2004

14. Dynamics of the Age Transition
A population with 35% or more of its people under age 15 is “young.”
A population with 12% or more of its people aged 65 or older is “old.”
As the proportion of young people increases relative to the total, the population “grows younger.”
An aging population is one in which the proportion of older people is increasing relative to the total.

15. The Age Structure
There are three major ways to quantify the age structure:
Average age of a population
Dependency ratio
Growth rates by age

16. Population Pyramids

17. Changes in Number and Rate of Growth at Specific Ages
China
India
Growth rate
Absolute change
Age Group
1980– 2000
0–4
–0.15
–3,004
0.84
17,606
5–9
–0.97
–21,938
1.26
25,339
10–14
–0.50
–12,434
1.55
29,112
15–19
–0.35
–7,358
1.79
30,747
20–24
0.63
11,590
1.78
26,618

18. Changes in Number and Rate of Growth at Specific Ages
China
India
Growth rate
Absolute change
Age Group
1980– 2000
25–29
1.52
31,810
2.36
31,516
30–34
3.25
60,631
2.81
32,939
35–39
3.53
53,163
2.93
30,165
40–44
2.71
35,142
2.74
24,902
45–49
3.11
39,765
18,338

19. Changes in Number and Rate of Growth at Specific Ages
China
India
Growth rate
Absolute change
Age Group
1980– 2000
50–54
2.27
22,796
2.12
13,572
55–59
1.69
13,395
2.15
11,304
60–64
2.26
15,068
2.36
10,077
65–69
2.78
14,957
2.56
8,375

20. Changes in Number and Rate of Growth at Specific Ages
China
India
Growth rate
Absolute change
Age Group
1980– 2000
70–74
2.75
10,615
2.74
6,121
75–79
3.09
7,278
3.20
4,113
80+
4.90
7,203
4.93
3,963

21. Stable and Stationary Populations
In a stable population neither the age-specific birth rates nor the age-specific death rates have changed for a long time.
A stable population could be growing at a constant rate or declining at a constant rate.
If a stable population is unchanging, we call it a stationary population.

22. Global Distribution of Younger and Older Populations

23. Age Structure of Immigrants to U.S., 2002

24. Age Pyramids for U.S. With and Without International Migration

25. Age Structure of U.S.

26. Changing Age Structures in China, U.S. and Mexico