Population Pyramids

How to read a population pyramid

• Imagine 2 sideways bar graphs

• Males – left• Females – right• Vertical axis

– age– year of birth

• Horizontal axis– Thousands– Millions– Percent

• Year• 3 types of pyramids…

Expansive type

• Triangle/pyramid• Base – widest part• Birth rate – high or low? Note the concave sides• Death rate – high or low?• Rate of Natural Increase – high or low? • Which stage of Demographic Transition Model?

Stationary type

• Half ellipse shape• Base – about the same width as middle• Birth rate – high or low?• Death rate – high or low? Note the convex sides• Rate of Natural Increase – high or low? • Which stage of Demographic Transition Model?

Constrictive type

• Base – narrower than middle• In extreme cases, upside-down pyramid• Birth rate – high or low?• Death rate – high or low?• Rate of Natural Increase – high or low? • Which stage of Demographic Transition

Model?

Asymmetry in Pyramids• typically, most pyramids show symmetry. Any asymmetry means . . .a.) there is something that happened/happens that accounts for a difference in female and male population – examples: war, restrictive population policies, migrant workforceb.) there was a baby boom

Population Pyramids for Several US Cities & Towns

(Upper left corner is the whole US.)

Dependency Ratio• Compares population of

dependents (children and elderly) to working-age population

• 0-14• 15-64• 65+• Why do we use these ages?• What might be some

problems with using these ages? Percent of population under age 15

(darker color means higher percent)

Goldilocks Moment

• Too hot! Too cold! Just right.• Too young! Too old! Just right.

• Low dependency ratio• Not too many children or elderly• Good for economy – why?

More pyramids to explore• Immigrants to US from various countries http://www.migrationinformation.org/DataHub/pyramids.cfm • US 1850-2000 http://vis.stanford.edu/jheer/d3/pyramid/shift.html - but link doesn’t work• Canada 1921-2009 http://strategy.sauder.ubc.ca/antweiler/edutainment/pyramid.pdf • Several major countries 1950-2050 http://visualization.geblogs.com/visualization/aging/ • Australia 1971-2056

http://www.abs.gov.au/websitedbs/d3310114.nsf/4a256353001af3ed4b2562bb00121564/ca0b3137794a766bca256f6c0078cb0b!OpenDocument

• World 1950-2100 http://populationpyramid.net/ • Various, including some historical US, and WWII Germany

http://gero.usc.edu/AgeWorks/core_courses/gero500_core/demographics_lect/index_a.htm • UK vs. Mozambique

http://www.bbc.co.uk/schools/gcsebitesize/geography/population/population_change_structure_rev5.shtml

• UK 1971-2085 http://www.neighbourhood.statistics.gov.uk/HTMLDocs/dvc1/UKPyramid.html • China 1950-2050 http://www.china-europe-usa.com/level_4_data/hum/011_7a.htm • India http://populationcommission.nic.in/facts1.htm • Japan 1950-2050 http://econviews.wordpress.com/2011/03/19/japans-demographic-crisis-part-2/

Connecting to your project• Think about the country that you are researching for your Status of Development

Project. – If you’ve already looked at your country’s population pyramid, use what you remember

about it.– If you haven’t looked at it yet, make an educated guess based on what you know about

the country.

• Questions to consider:– How can you use what we learned today in your project? – What shape is your country’s population pyramid? Why? – What can you tell about your country from its pyramid?– Is there anything distinctive in your country’s pyramid? Why? What does it mean?

• Examples - Very high or very low numbers of people in certain age groups? A sex imbalance? Etc.