Determinants of Population Size and Growth-Birth Rate, Death Rate and Migration

There are three main factors which determine the population size and growth of a given country. There three factors are birth rate, death rate and migration.

Birth rate

The birth rate 9or natality rate) of a country refers to the rate at which children are being given birth to in that country. Generally, high birth rate may lead to increase in population or over population while low birth rate can lead to low population. Birth rate can be influenced by:

1. Early marriage: In many communities in the developing nations or Islamic regions, people encourage early marriage and this gives rise to increase in population as many children being given birth to.

2. Desire for large families: In most communities in developing nations and some races making up a facet of the American population, people tend to have many children as this places them in a special class or gives them better grounds of residency. Some men even go ahead to marry many wives just to achieve this.

3. Religious belief: While certain religion, eg, Christianity discouraged polygamy, others like Islam encourage marrying of many wives that will give birth to many children.

4. Improved medical services: as a result of improved medical services, death rate has reduced while birth rate has been boosted.

5. Government aids: Where the government increases the aids it gives to people, families are encouraged to have more children thereby increasing the population.

6. Improved standard of living: This encourages men to marry more wives in favorable communities thereby increasing birth rate.

Death rate

Also known as mortality rate of a country and it refers to the rate at which people (both adult and children) die in a country. Generally, high death rate leads to population decrease or low population, while low death rate leads to increase in population. Death rate can be influenced by:

1. Ratio of male to female: When there are more males than female, there will be a low child-bearing rate, which will reduce the population.

2. Poor medical services: When medical services are poor, death rate tends to increase.

3. High rate of infant mortality: High rate of infant mortality leads to decrease in population.

4. Poverty: High level of poverty among the people leads to high death rate, as such people may not have the means of taking care of their families.

5. Natural disasters: Natural disasters like earthquakes, flooding can lead to high death rate.

6. Man-made disasters: The occurrence of man-made disasters like wars, conflicts, pollutions etc, is capable of leading to high death rate.


This is the movement of people from one geographical area to another, involving permanent or temporary residence or settlement. In migration, the region where people are leaving is called the source region while the region where people are entering is called the receiving or destination region. There are two major types of migration. These are emigration and immigration. Emigration is the type of migration in which people leave their own countries, i.e movement out of a country. Immigration is the type of migration in which people enter into another country, ie, movement into another country. Migration from one place to another takes different forms, these include:

1. Rural-urban migration: This is the movement of people from rural areas.

2. Rural-rural migrations: This is the movement of people from one rural area to another rural area or from one ghetto to another ghetto.

3. Urban-rural migration: This is the movement of people from one Urban center to rural areas (especially the missionaries or for creating establishments).

4. Urban-Urban migration: This is the movement of people from one Urban center ( Town or city) to another.

5. International migration: This is the movement of people from one country into another.

6. Seasonal migration: This is the movement of people from one place to another at a particular season, maybe going abroad during summer holidays.

Stabilzing these three factors can contribute to a very strong economy. The United states of America is a good example of a nation which has created an equilibrium between these three factors and still find huge success. It has been estimated that immigrants now contribute to 30% of the nation’s economy. Definitely, the United states visa lottery is not just there for a game-it has a purpose in which it is realizing.

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