Social Demography 2024-2025
Inhoudsopgave
Chapter 1: Basic Calculations ....................................................................................................... 2
Chapter 2: Size & Evolution of the World Population ....................................................................... 4
Chapter 3: Population structure .................................................................................................... 9
Chapter 4: Demographic Data ...................................................................................................... 14
Chapter 5: Natality, fertility and reproduction ............................................................................... 17
Chapter 6: Nuptiality ................................................................................................................... 29
Chapter 7: Mortality ..................................................................................................................... 34
Chapter 8: Migration .................................................................................................................... 38
1
,Chapter 1: Basic Calculations
Population: a delimited collection of individuals/elements that have something in
common
à often geographic and historical criteria
But in reality much more complex (what with non-o=icial population? Students, expats,
sans papiers…)
Demography: study of population structures and processes
- Structures: distribution of the population according to relevant characteristics
(biological or socio-economic)
- Processes: population dynamic through demographic events
Fundamental demographic equation
2 elements:
- Stock statistics (N(0) and N(T)) that describe the state of a population
- Movement statistics: number of events during a specific time in interval
Goal of calculations in demography: eliminate/neutralize the impact of the size and
structure of the population on demographic events in order to make them comparable.
Indicators of composition:
- Rate: relation of one population subgroup to another subgroup
- Proportion: relation of a population subgroup to the entire population
- Percentage: same as proportion but multiplied by 100
Indicators of dynamic processes
- Counts: absolute number of events in a specific time period (and area)
2
, - Probability: number of events/number of persons who can experience the event
at the beginning of the interval
- Risk or rate: number of demographic events in a population during a specified
time period (usually a year) divided by the population at risk of the event
occurring during that time period. Denominator = persons years lived
Basic demographic rates: crude rates
- Crude birth rate
- Crude death rate
- Crude immigration rate
- Crude emigration rate
- Crude growth rates
Usually expressed per 1000 (and thus multiplied by 1000). This is the di=erence between
the crude birth rate and the crude death rate. Crude migration growth rate: di=erence
between the crude immigration rate and the crude emigration rate.
Crude rates only take the size of the population into account, not the structure of the
population. It doesn’t take into account the impact of age and sex but other
demographic indicators aim at neutralizing the impact of age and sex.
Methods for person years lived
3
, Method of the midyear population:
Only valid if population grow linearly and if the period of reference (0,T) it not too
long.
Method of the mean population:
If the period of reference (0,T) is not too long we can estimate the number of
person years by the arithmetic (rekenkundig) mean of the population at the
beginning and the population at the end of the period of observation multiplied by
T. When annual data are available, it is better to take the mean of the T annual
mean populations.
Now that we know how to calculate PY we can calculate rates because they need PY in
the denominator.
Chapter 2: Size & Evolution of the World Population
The population explosion?
- Population growth in pre-modern times
o World population of 10-250 million at the time of ancient Rome
o Slow but gradual growth, cyclical
o Higher density à di=usion of illnesses, wars
o Vulnerable to crop failure, climatological changes, famines,
undernutrition (lower fecundity)
o High fertility and high mortality
o European population: strong shrink since the 3rd century AD
- 17th – 14th century: gradual population growth
o Especially in fertile areas
o Expansion of the agricultural land
o Increase of productivity (iron plough, three-fields system)
- Demographic crisis in 14th centuty
o Black death 1347-1351
o By 1400: 2/5 of the population had disappeared
o Also general mortality crisis in the 12th – 14th century: fragmented soil, less
fertile soils for exploitation, increasing weed prices
Causes of population growth
4
Inhoudsopgave
Chapter 1: Basic Calculations ....................................................................................................... 2
Chapter 2: Size & Evolution of the World Population ....................................................................... 4
Chapter 3: Population structure .................................................................................................... 9
Chapter 4: Demographic Data ...................................................................................................... 14
Chapter 5: Natality, fertility and reproduction ............................................................................... 17
Chapter 6: Nuptiality ................................................................................................................... 29
Chapter 7: Mortality ..................................................................................................................... 34
Chapter 8: Migration .................................................................................................................... 38
1
,Chapter 1: Basic Calculations
Population: a delimited collection of individuals/elements that have something in
common
à often geographic and historical criteria
But in reality much more complex (what with non-o=icial population? Students, expats,
sans papiers…)
Demography: study of population structures and processes
- Structures: distribution of the population according to relevant characteristics
(biological or socio-economic)
- Processes: population dynamic through demographic events
Fundamental demographic equation
2 elements:
- Stock statistics (N(0) and N(T)) that describe the state of a population
- Movement statistics: number of events during a specific time in interval
Goal of calculations in demography: eliminate/neutralize the impact of the size and
structure of the population on demographic events in order to make them comparable.
Indicators of composition:
- Rate: relation of one population subgroup to another subgroup
- Proportion: relation of a population subgroup to the entire population
- Percentage: same as proportion but multiplied by 100
Indicators of dynamic processes
- Counts: absolute number of events in a specific time period (and area)
2
, - Probability: number of events/number of persons who can experience the event
at the beginning of the interval
- Risk or rate: number of demographic events in a population during a specified
time period (usually a year) divided by the population at risk of the event
occurring during that time period. Denominator = persons years lived
Basic demographic rates: crude rates
- Crude birth rate
- Crude death rate
- Crude immigration rate
- Crude emigration rate
- Crude growth rates
Usually expressed per 1000 (and thus multiplied by 1000). This is the di=erence between
the crude birth rate and the crude death rate. Crude migration growth rate: di=erence
between the crude immigration rate and the crude emigration rate.
Crude rates only take the size of the population into account, not the structure of the
population. It doesn’t take into account the impact of age and sex but other
demographic indicators aim at neutralizing the impact of age and sex.
Methods for person years lived
3
, Method of the midyear population:
Only valid if population grow linearly and if the period of reference (0,T) it not too
long.
Method of the mean population:
If the period of reference (0,T) is not too long we can estimate the number of
person years by the arithmetic (rekenkundig) mean of the population at the
beginning and the population at the end of the period of observation multiplied by
T. When annual data are available, it is better to take the mean of the T annual
mean populations.
Now that we know how to calculate PY we can calculate rates because they need PY in
the denominator.
Chapter 2: Size & Evolution of the World Population
The population explosion?
- Population growth in pre-modern times
o World population of 10-250 million at the time of ancient Rome
o Slow but gradual growth, cyclical
o Higher density à di=usion of illnesses, wars
o Vulnerable to crop failure, climatological changes, famines,
undernutrition (lower fecundity)
o High fertility and high mortality
o European population: strong shrink since the 3rd century AD
- 17th – 14th century: gradual population growth
o Especially in fertile areas
o Expansion of the agricultural land
o Increase of productivity (iron plough, three-fields system)
- Demographic crisis in 14th centuty
o Black death 1347-1351
o By 1400: 2/5 of the population had disappeared
o Also general mortality crisis in the 12th – 14th century: fragmented soil, less
fertile soils for exploitation, increasing weed prices
Causes of population growth
4
