Demography

Question 1

Give the 2 main axes of demography!

Answer 1

Question 2

What is the age-sex pyramid? What types are there?

Answer 2

It shows the distribution of men and women in age groups at a given time.

Question 3

What reproduction ratios are there? Explain them!

Answer 3

Gross reproduction rate (GRR):

Sum of age-specific female fertility rates (births of daughters) for all reproductive age groups for a particular period

OR

GRR = TFR x proportion of female births

It indicates the average number of daughters a woman would have if she survived all of her childbearing years, which is roughly to age 49, subject to the age-specific fertility rate and sex ratio at birth throughout that period.

Net reproduction rate (NRR):

The average number of daughters that would be born to a female if she passed through her lifetime conforming to the age-specific fertility and mortality rates of a given year.

Question 4

What birth demographic terms are there?

Answer 4

Singleton: 1 offspring in the same gestation period

Multiple: ≥ offspring in the same gestation period

Preterm (PTB): birth of an offspring before 37 completed weeks

Low weight (LBW): the offspring’s weight < 2.5 Kg

Question 5

How do you define a natality event (birth)?

Answer 5

It means live birth that occurs when a fetus exits the mother and shows signs of life:

• Heartbeat
• Pulsation of the umbilical cord
• Any voluntary movements

Complete birth: entire separation of infant from mother by cutting the umbilical cord after 42 completed weeks of gestation

Question 6

Define life expectancy!

Answer 6

Life expectancy:

Average number of years an individual of a given age is expected to live, if current age-specific mortality rates continues to apply (calculated separatly for men and women).

Every cohort had different experiences in its earlier life that may have influenced its mortality rate of a given year.

Life expectancy at birth:

Average number of years a newborn is expected to live if current mortality structure persists throughout its life.

Question 7

What is the law of 70?

Answer 7

If a population is growing at a constant rate of 1% per year, it can be expected to double approximately every 70 years.

If the rate of growth is 2% then the expected doubling time is at 70/2 = 35 years.

Question 8

What happens during the demographic/epidemiologic transition?

Answer 8

Early stage: Decline in mortality

• Growing productivity of agriculture:
  
  • Disappearance of famine
  • Better food quality
• Improving (public) health:
  
  • Disappearance of epidemics (vaccination)
  • Discoveries in medicine
  • Improving sanitation
• Socio-cultural changes:
  
  • Improvements in personal hygiene

Late stage: decline in crude birth rate

Question 9

What happens during the pre-transition era?

Answer 9

High mortality rates:

• Famine
• War
• Epidemics (e.g. plague)

High natality:

• Traditional actions for birth control:
  
  • Later marriage or none
  • Long breastfeeding
  • No pre-marriage intercourse

Short life expectancy

Question 10

What happens post-transition era?

Answer 10

• Low(er) mortality
• Low natality (modern contraception)
• Long life expectancy

Question 11

What are the demographic/epidemiology transitions?

Answer 11

Question 12

What are the sources of demographic data for each axis of demography?

Answer 12

Structure:

• Census
• Calculation
• Microcensus (intercensus surveys)

Population dynamic:

• Registration of births and deaths (civil registration)
• Location of residence registry
• Immigration registry
• Cause of death - death certificate (ICD)