Population, Migration, and Demographic Change
Demographic Key Terms and Metrics
Crude birth rate is defined as the total number of live births per individuals in the population per year.
Crude death rate is defined as the total number of deaths per individuals in the population per year.
Natural change is defined as the difference between the crude birth rate and the crude death rate:
If the birth rate is higher than the death rate, then there is a natural increase in the population. If the death rate is higher than the birth rate, there is a natural decrease in the population.
Factors Influencing Population Change Over Time
Populations undergo change over time due to several critical factors that impact mortality, fertility, and movement:
Food security plays a central role, as stable access to food prevents starvation and improves general population survival.
Sanitation and water systems control the spread of infectious disease and maintain overall public health.
Medical improvement brings enhanced treatment options, modern healthcare infrastructure, and extended life expectancy.
War causes severe demographic disruption, increased mortality rates, and population displacement.
Migration alters population numbers as individuals move into or out of specific geographical areas.
Fluctuations in the total number of births and deaths directly impact overall demographic growth or decline.
Factors Contributing to Declining Death Rates
Death rates decrease due to specific public health and healthcare enhancements:
Having more doctors enables a higher volume of patients to be diagnosed, managed, and treated.
Better hygiene practices lead to a reduced risk of infection across communities.
Access to clean drinking water prevents waterborne illnesses and significantly reduces overall mortality.