Michael Metz 10-8-11 Chapter 2, Key Issue 2 Natural Increase What are 3 ways geographers measure population change? Geographers most commonly measure population change in a country or the world as a whole through 3 measures: Crude Birth Rate (CBR) Crude Death Rate (CDR) Natural Increase Rate (NIR) What does the NIR affect? The doubling time is affected by the NIR Fertility For what do geographers use the total fertility rate (TFR)? Geographers use the TFR to measure the number of births in society. Mortality What are 2 useful measures of mortality? Two useful measures of mortality are: The infant mortality rate (IMR) Life expectancy Vocabulary: CBR- Total number of live births annually per 1,000 people. CDR- Total number of deaths annually per 1,000 people. NIR- The percentage by which a population grows per year. Doubling Time- Number of years needed to double a population TFR- The Average number of births in a society Life Expectancy- Measures the average number of years a baby can expect to live at current mortality levels. IMR- Annual number of deaths of infants under 1 year of age Where has the World’s Population Increased?