Understanding Population Dynamics: Birth, Death, and Fertility Rates
Mortality Rate
The mortality rate depends on factors such as food and resources, and hygienic-sanitary conditions. High mortality rates are observed in Russia and Africa.
Infant Mortality Rate (IMR):
- [Total deaths of children under one year (x) / total births (x)] · 1000
- IMR high: above 35‰
- IMR moderate: between 15 and 35‰
- IMR low: up to 15‰
Infant mortality in underdeveloped countries is often caused by infectious or parasitic diseases.
Once we have the birth rate and death rate, we can calculate the vegetative or natural growth of the population.
TM = TN – TM or natural vegetative growth.
Fertility Rate
Fertility Rate (5.3): The average number of children per woman. There are several formulas to calculate it:
General or Gross Fertility Rate:
Number of births in a year (x) among women of childbearing age · 1000
_______________________________________________________
Total women of childbearing age [15-49 years]
Fertility Rate by Age:
Number of births in a year among women between 30 and 35 years · 1000
_______________________________________________________
Total women between 30 and 35 years
Synthetic Index of Fertility (ISF):
Sum of different Fertility Rates by Age (TFE)
_______________________________________ = Average children per woman
1,000
Because there is a growing need for 2.1 children per woman. All developed countries are below the replacement level, while underdeveloped countries are well above it.
Causes of Low Fertility in Developed Countries
The causes of low fertility in developed countries include a delay in the age of marriage or childbearing, the increased incorporation of women into the workplace, and the widespread use of contraceptives. As fertility is so low in these countries, many have tried to incentivize births by supporting people to have more children, donating money, and providing subsidies. Creating free kindergartens and increasing maternity leave are also common measures.
Policies in Underdeveloped Countries
In underdeveloped countries, on the contrary, anti-natalist policies have been implemented, such as promoting the use of contraceptives, creating family planning services, and facilitating abortion and sterilization. There are extreme cases such as China, where having more than one child results in a fine (one-child policy).
Other Demographic Indicators
Marriages: The number of marriages concluded in one year per thousand inhabitants. In the past, this indicator was useful, but it has now lost much of its value. However, it has generally served in demographic studies of a few years ago. For example, marriages can influence the total number of inhabitants. When marriages are delayed, the number of children decreases.
Model of Demographic Transition
This is a theory that attempts to explain the evolution of a population over time. We will use Britain as an example, but this model can be applied to other countries. In principle, all countries must pass through these four phases.
1st Phase: Old Demographic Regime
This phase spans from prehistory to 1750.
- High and oscillating mortality, which fluctuates up and down.
- High and oscillating birth rate, which rises and falls.
- Therefore, there is no population growth.
We are in a rural society, where many children are born as insurance for the future and to work in the field. But at the same time, many people die. These oscillations are due to the so-called subsistence crises (crises caused by nature), which depended on good or bad harvests, and epidemics. Evidently, hygienic and sanitary conditions were very bad, and people died of things that people do not die of today. There is no country that is currently in this phase.
Transition
The transition is a theory that tries to explain how people from an old regime passed to a new regime. It has four phases. The demographic transition starts with the second phase.
* The old demographic regime: very high mortality rate, and oscillating high birth rate and also oscillating, so there is almost no demographic growth.
2nd Phase of Expansion (1750-1880)
- The first important feature is the decrease in mortality.
- Improvements in nutrition, sanitary-hygienic conditions.
- Discovery of the potato, which saved many people from famine. In Ireland, it was very important.
- In improving health, coal heating was invented.
- Also, the substitution of wool for cotton (which is much more hygienic).
Therefore, all this progress made mortality decrease.