Trends in Population (College Board AP® Human Geography)

Demographic Factors & Population Growth

• Population change must take into account the number of:

  • births

  • deaths

  • immigrants

  • migrants

• Demography refers to the study of the population, including its:

  • size

  • distribution

  • change over time

• The study of population change includes data for the birth rate, death rate, fertility rate, and infant mortality rate

  • The crude birth rate (CBR) is the number of live births per one thousand people in the population

    • While the crude birth rate indicates the population change in a country, the total fertility rate is a better indicator of social norms

  • The crude death rate (CDR) is the number of deaths per one thousand people in the population

  • The total fertility rate (TFR) is the average number of children a woman is expected to have during her childbearing years (ages 15–49)

    • If a country has a high TFR, women in that country are less likely to work outside the home and more likely to take on more traditional roles

    • If a country has a low TFR, women are more likely to pursue higher education, marry later, and work outside the home

  • The infant mortality rate (IMR) is the number of children who die during their first year per one thousand live births in a country

    • High infant mortality rates imply that a country has lower levels of development, less access to health care, and fewer government services such as water and electricity

• Doubling time refers to the amount of time it takes for a population to double in size

  • The shorter the doubling time, the faster the rate of population growth

• Life expectancy is the average number of years an individual is expected to live

  • High life expectancy correlates with more developed countries and greater access to health care

  • Low life expectancy correlates with developing countries and less access to health care and government services

• Though birth rates have declined over time, longer life expectancies and lower death rates mean that the world’s population continues to expand

Natural Increase

• The rate of natural increase (RNI) (also known as the natural increase rate or NIR) is expressed as the Crude Birth Rate minus the Crude Death Rate divided by 10 (CBR=CDR/10)

  • A positive RNI means a population is growing 

  • A negative RNI means a population is shrinking

• It is important to note that the RNI does not take account of immigration or emigration

Factors Affecting Fertility, Mortality, & Migration

• Factors that have resulted in lower mortality rates and higher life expectancies include:

  • increased food production

  • better medical care

  • advances in sanitation systems

• Factors affecting fertility, mortality, and migration may be:

  • social

  • cultural 

  • political (government)

  • economic

Social factors

• Social factors include:

  • the role of genders in society

  • whether family planning is socially acceptable

  • the average age at marriage

  • traditional family size values 

• If marrying young is culturally expected, the fertility rate is going to be higher because women have a longer period over which they are likely to have children

Cultural factors

• Cultural factors include:

  • that some religions may forbid birth control

  • how acceptable it is to seek health care, versus using home remedies to cure diseases

Political factors

• Governments can play a role in population trends including 

  • policies that limit or encourage children

  • supporting and funding healthcare for society

  • encouraging or discouraging immigration into the country

Economic factors

• Economic factors that affect population trends include:

  • The number of women working in the economy

    • The more women in the workforce, the lower the fertility rate tends to be

  • The overall level of economic development

    • Higher economic development tends to correlate with lower fertility rates, lower crude birth rates, lower crude death rates, and longer life expectancies

    • Lower levels of economic development tend to correlate with higher fertility rates, higher crude birth rates, higher crude death rates and decreased life expectancies