Which statement represents the basic demographic equation?

Which statement represents the basic demographic equation?

• A. Growth rate = births - deaths + net migration
• B. Growth rate = births + deaths + net migration
• C. Growth rate = births - deaths
• D. Growth rate = net migration - births - deaths

Answer: (A)

Population change is determined by births, deaths, and net migration. Births add people, deaths subtract people, and net migration (the difference between those who move in and those who move out) can add to the population if there are more entrants than exits. So the growth rate is calculated as births minus deaths plus net migration. This correctly accounts for each factor’s impact and direction. Other formulations either treat deaths as adding to population, omit migration, or assign the wrong sign to net migration, which would misstate how the population changes.

Population change is determined by births, deaths, and net migration. Births add people, deaths subtract people, and net migration (the difference between those who move in and those who move out) can add to the population if there are more entrants than exits. So the growth rate is calculated as births minus deaths plus net migration. This correctly accounts for each factor’s impact and direction. Other formulations either treat deaths as adding to population, omit migration, or assign the wrong sign to net migration, which would misstate how the population changes.