# POPULATION GEOGRAPHY Measurements and Metrics AP HG SRMHS

• Slides: 16

POPULATION GEOGRAPHY Measurements and Metrics AP HG SRMHS Mr. Hensley

Population Geography • The scientific study of population characteristics is called demographics • Typical demographics include birth rate (fertility), death rate (mortality) population density and family size • Population geography connects demographics to location and region

Rates, Cohorts and Per Capita • Rates refer to the frequency of an event within a population made up of all ages • Cohort measures are data for one specific age group • Per capita means we are controlling for size or taking it to an individual level • Per capita is the default

Crude Rates • Expressed as x per thousand • CBR: crude birth rate • CDR: crude death rate • NIR: Natural Increase Rate = CBR-CDR • NIR divided by 10 gives you percentage change in the population

Rule of 72 • Quick and easy way to determine doublings • X = NIR • 72/NIR = time (in years) it takes for population to double • Works for any percentage metric • Make sure you are using percentages!

Exercise • Current NIR is 1. 2% how long until we double Earth’s population? • Club of Rome (1970) NIR was 2. 2% – how long would it take to double?

NIR Worldwide

Another Metric: TFR • Total Fertility Rate or TFR is the average number of children each woman will have in her lifetime • Worldwide TFR is 2. 7 • TFR below 2. 0? Problem? • USA TFR about 2. 2 • Replacement rate is 2. 1

TFR World Map

Infant Mortality Rate (IMR) • Count up the total number of deaths in children one year old or younger • Compare that to total live births - IMR • Expressed as the number of deaths per 1, 000 infants • Easily converted to percentage

What is IMR measuring? • Primarily, access to medical care • Also, quality of medical care • Also, access to regular food supplies • Safety and security • To a lesser extent: availability of birth control?

IMR Worldwide

Population Pyramids • A population pyramid is a graphical representation of age and sex distribution in a given nation • Dependency ratios: how many children and elderly supported by the 18 -65 cohort • The broader the base the faster the growth • Asymmetries - China

Three Different Pyramids

What’s Going on? Predictions?

Why is there a difference?