The document is a presentation on the determinants and dynamics of age and sex structure within the context of a demography course. It covers definitions, the importance of age-sex structure, methods of analysis including population pyramids, and compares sex and age distributions in developed and developing countries. Additionally, it discusses the impacts of age-sex structure on population processes such as birth, death, migration, and the potential for errors in census data collection.

1. A presentation on-
“Determinants and the Dynamics of Age and Sex Structure”

2. Course Title: Demography
Course No: Soc 3105
3rd year, 1st term
Submitted to-
Dr. Md Abdul Jabbar
Professor,
Sociology Discipline,
Khulna University
Khulna- 9208 Submitted by-
Faiza Atkia Keya
Student ID: 181646
Sociology Discipline
Khulna university
Khulna- 9208

3. Outlines
 Definition of age- sex structure;
 Age- sex pyramid;
 Age- sex structure;
 Describing age structure;
 Age structure( past, present, future);
 Proportion of age structure;
 Population pyramid
 Population pyramid of Bangladesh- 2010,
2019;
 Population pyramid of Denmark, 2015;
Population pyramid of Europe, 2019;
World population pyramid, 2003;
 Describing sex structure;
 Determinants of sex structure;
 sex ratio patterns;
 World human sex ratio, 2011;
 Sex ratio by countries;
 Contrasts between more and less developed
countries;
 Impacts of age- sex structure;
 Importance of age- sex structure;
 errors can occur;
 Use and limitations;
 Conclusion;

4. Introduction
 Demography deals not only with population size and growth but also deals with population
composition.
 The most important dimensions of composition are undoubtedly Age and Sex.
 Society construct roles and status on the basis of age and sex more than any other
characteristics. Similarly, nations consistently include questions on age and sex in their census
questionnaires.
 So, dependence on the importance of age and sex structure, many demographers give it a
special label: Population Structure.

5. Defining age and sex structures
 Demographers define sex as someone's biological and physiological characteristics, as opposed
to gender. whereas, gender refers to socially constructed roles assigned by society to women and
men.
 The United Nation define age as the interval of time between the date of birth and the date of
census, expressed in complete solar years.
 Age and Sex structure of a population determined by the number or proportion of males and
females in each category. The age and sex structure of a population is the cumulative result of
past trends in fertility, mortality and migration.
 Population Structure resulting from individual survival, dispersal, and reproduction determines
of future survival, dispersal and reproduction of individuals.

6. Age- Sex pyramid

7. Age and Sex structure

8. Describing Age structure
 The age structure of a population is the distribution of people of various ages.
 Demographers use some basic techniques for describing age and sex structure-
 Frequency distribution
 Percentage distribution
 Ratios
 Bar graphs
 Basic graphical tools-
 Graphical analysis
 population pyramids
Graphical cohort analysis.

9. Age structure ( past, Present and Future)

10.  Age percentage: To compute the age percentage, one have to multiply the entry in each age- sex
category by one hundred, then divided by the total of population in that same age-sex category.
The formula would be-
 Age dependency ratio: A convenient way to compare the relative size of any two numbers is by
constructing a ratio, dividing one number by the another. When applied to age distributions, the most
frequently used is the age dependency ratio. The formula is-
( number of people aged 0 to 14)+( number of people aged 65)
Total Dependency ratio = × 100
number of people aged 15 to 64
(population in age and sex class)× 100
population in all age classes of same sex

11.  The total dependency ration can be decomposed into the child dependency ratio and the aged
dependency ratio.
number of people aged 0 to 14
Child dependency ratio = × 100
number of people aged 15 to 64
number of people aged 65 and over
Aged dependency ratio = × 100
number of people aged 15 to 64

12. Measuring Dependency Ratios
Source: US census bureau international data base

13. Old- Age dependency ratio

14. Groups in population
 ˂ 1 year infant
 0- 18 children
 10- 19 adolescents
 15- 24 youth
 10- 24 young people
 0- 14 dependent people
 15-64 working age
 65+ or 60+ elderly
75+ old elderly
80+ disabled elderly

15. Classification of population
 Population may be classified based on the relative proportions in the young and elderly
cohorts.
 Young population has 35% of its members under age 15 years.
 Old population has 10% of its members over 65 years.
 Problems may arise when a population exhibits both characteristics.
 the median age allows for a manually exclusive classification.

16. Population pyramid
 population pyramid visualize the demographic structure of a population.
 The width represents the size of the population of the given age; women on the right and
men on the left.
 The bottom layer represents the number of newborns and above it the numbers of olders
cohort.
 Population pyramid is the basic procedure for accessing the quality of census data on
age and sex.

17. Population pyramid
 Displays the size of population enumerated by each age group or cohort by sex.
 The base of the pyramid mainly determined by the level of fertility in the population.
 While how fast it converges to peak is determined by previous levels of mortality and fertility.
 The levels of migration by age and sex also affect the shape of the pyramid.

18. Population pyramid

19. Population pyramid of Bangladesh,2010

20. Population pyramid of Bangladesh, 2019

21. Population pyramid of Denmark,2015

22. Population pyramid of Europe, 2019

23. World population pyramid,2003

24. Describing Sex structure
 The demographers often describe the sex composition of population by comparing the number
of persons of each sex with a ratio. The sex ratio is the number of men divided by the number of
women multiplied by a constant of 100;
Men
× 100
Women
 Sex ratios can be computed not only for total populations but also for classes within those
populations. Demographer frequently find it helpful to pay attention to sex composition at
different age levels.

25. Determinants of sex structure
 Affected by relative pattern of-
 Birth
 Death
 Migration
 wars ( major wars also have lower sex ratios)
 Son preference ( the tendency for parents to prefer male children over female children)

26. Sex ratio patterns
 Shows a constant pattern for most countries.
 Usually highest at birth, about 102 to 105 males per 100 females.
 The probability of dying at birth is higher for male children.
 The sex ratio is almost even in the early adult years and decreases further in early old age.
 During old age, the ratio is at its lowest as life expectancy is on average 3- 5 years higher for
females.
 Men mature slower and die earlier than women.

27. World human sex ratio(2011)

28. Sex ratio by countries
More males
than females
More
females
than men
Same number
of male and
female

29. Contrasts Between More- Developed and Less-
Developed countries
 Age Structure:
• The less- developed regions have a higher proportion of their population under fifteen years of
age.
• In contrast, the more- developed countries generally have higher proportion of their population
aged sixty- five and over.
• In regions, such as Latin America and Caribbean, Asia, Oceania, Northern America has the
percentage under age fifteen falls in a closer range from higher to lower. Europe is the only
country with a greater proportion in the older ages than in younger ages.

30. Contrasts Between More- Developed and Less-
Developed countries
Sex Structure:
• For the less- developed regions, the population pyramid is almost symmetrical with a little
change.
• In contrast, the pyramid for the more- developed regions has a marked rightward, or female ,
lean as it rises to the older age categories.
• In both regions, men are slightly predominant in the earliest ages.
• In the higher ages, women tends to outnumber the men more and more.
• Female predominance in the older ages is a feature of more- developed countries.

31. Contrasts Between More- Developed and Less-
Developed countries

32. Population pyramid types

34. Impact of Age-Sex Structure upon the Population
Processes
 Birth, death and migration varies with age and sex. And thus, all of the crude rates affected by the
age- sex structure of the population.
 Mortality: Small mortality rate during infancy declines to almost no mortality during youth,
climbs gradually through the middle years and then rises more rapidly thereafter. The general “J”
shape of age distribution of mortality is almost universal, although the lean of the shape may vary.
Everywhere sex influences mortality.
 Fertility: Fertility rises rapidly in the late teens to a peak in the late twenties to early thirties,
then declines to negligible levels in the mid- forties. The advancement of fertility medical
technology and vast use may eventually play a bigger role in driving later ages child bearing.
 Migration: Although the ways that age and sex influence mortality and fertility are
fundamentally biological, it may come as a surprise that age also strongly affects migration.
Universally, contemporary mobility is at its peak between the late teens and the mid thirties.
Mobility also differs by sex.

37. World median ages (in years)

38. Importance of age-sex structure
 Planning process-
• health services
• education programs
•Labor supply
 Demographic study and research purposes for social science, economists and gender studies.
Studying population dynamics-
• fertility
• mortality
• migration

39. Importance of age-sex structure
 Insight on quality of census enumeration.
 Having a strong effect on other characteristics of a population-
• determined by fertility, mortality and migration
• follows fairly recognizable patterns

40. Errors can occur-
 Two kinds of errors can occur in quality of census data, which Shryock and Siegel call-
1. Underenumeration
2. Misreporting
(Shryock,1976, p- 115)
 Underenumertion: Underenumeration of an age and sex class means falling to count
somebody who would have fallen into that class. The errors arising from underenumeration are
also called coverage errors or undercounts.
 Misreporting: Misreporting means counting somebody but misallocating him or her among the
age sex categories.

41. Errors can occur-
 Significant clashes in age-sex structure due to extraordinary events-
o High migration
o War
o Famine
o HIV/ AIDS
o Epidemic and others.

42. Uses and limitations
 The major limitation of age and sex structure is that it is not possible to derive separate
numerical estimates of the magnitude of coverage and content error on the basis of such analyses
alone.
 It is often possible to assess particular types of errors which are likely to have affected the
population counts for particular segments of the population. Estimates of coverage error from
other sources often are required to verify the observations.

43. Conclusion
The age and sex structure of a population enumerated is typically the first step taken in
evaluating a data collection operation by means of demographic methods. Demographic
methods provide a quick and expensive indication of the general quality of data.
Evidence on the specific segments of the population in which the presence of error is
likely “Historical” information which may be useful for interpreting the results of
evaluation studies based on other methods, and in determining how the collected data
should be adjusted for use in demographic studies.

44. References
Bloom David, D. c. (2003). The Demograpgic dividend: A new perspective on the Economic
consequenses of population change. Santa Monica: CA:RAND.
J, c. A. (1972). The growth of Human Population: A mathematial Investigation. Princeton, NJ:
Princeton University Press.
James Gribble, B. J. (2012). Achieving a Demographic dividend. Population Bulletin, 67(2).
S. Henry Shryock, S. J. (1976). The Methods and Materials of Demography (condensed edition by
Edward Stockwell ed.). New York: Academic Press.