Demographic Basics


  • Fertility
  • Crude Birth Rate (CBR) the number of births in one year in a country, divided by the country's population, and multiplied by 1000. 
  • Fertility rate Number of live births, divided by the female population of child bearing age, multiplied by 1000
  • Natality birth as a component of population change


  • Mortality
  • Crude Death Rate (CDR) divide the number of deaths in one year by the population and then multiply by 1000. 

Calculating change

  • Natural increase = births deaths
  • Growth rate = Natural increase +- net migration
  • Doubling time = the amount of time it would take for a given population to double
  • The Rule of 72: 72 ÷ growth rate = years to double
    • example: if a country's growth rate is 3%, the population will double in about 24 years 
    • example: if a country's population doubles in 18 years, its growth rate is about 4%
  • History of world population

Young vs old populations

  • If more than 35% of a country's population is under the age of 15, it is considered a young population 
  • If more than 15% of a country's population is over the age of 65, it is considered an old population 

Life expectancy

  • The average number of years a person could expect to live (if current mortality trends continue)
  • All Americans: 76.9
  • All Males: 74.1
  • All Females: 79.5

Demographic Transition

  • the shift from high to low levels of both fertility and mortality
  • more info here