# Birth rate

File:Birth rate figures for countries.PNG
Countries by birth rate, CIA map, not dated

In demography, natality, or rather the crude birth rate (CBR) of a population is the number of childbirths per 1,000 people per year. It can be mathematically represented by $CBR = \frac{n}{p}{1000}$ where n is the number of childbirths in that year, and p is the current population. This figure is combined with the crude death rate to produce the rate of natural population growth (natural in that it does not take into account net migration).

Another indicator of fertility is frequently used: the total fertility rate — average number of children born to each woman over the course of her life. In general, the total fertility rate is a better indicator of (current) fertility rates because unlike the crude birth rate it is not affected by the age distribution of the population.

Fertility rates tend to be higher in less economically developed countries and lower in more economically developed countries.

## Other methods of measuring birth rate

General fertility rate (GFR) – This measures the number of births per 1,000 women aged 15 to 45.

Standardised birth rate (SBR) – This compares the age-sex structure to a hypothetical standard population.

Total fertility rate (TFR) – The mean number of children a woman is expected to bear during her child-bearing years. It is also independent of the age-sex structure of the population.

## Factors affecting birth rate

• Pro-natalist policies and Anti-natalist policies from government
• Abortion rates
• Existing age-sex structure
• Social and religious beliefs - especially in relation to contraception
• Female literacy levels
• Economic prosperity (although in theory when the economy is doing well families can afford to have more children in practice the higher the economic prosperity the lower the birth rate).
• Poverty levels – children can be seen as an economic resource in developing countries as they can earn money.
• Infant Mortality Rate – a family may have more children if a country's IMR is high as it is likely some of those children will die.
• Urbanization
• Homosexuality - homosexual men and women most commonly do not become mothers and fathers, decreasing the number of births per year.
• Typical age of marriage
• Pension availability
• Conflict