People who study population trends have developed a special type of bar graph to show how the population of an area is divided by age and gender. It is called a POPULATION PYRAMID.

Interactive exercise. Assistance may be required. Scroll over the image below to learn more about the parts of the population pyramid.

The information that can be derived from these bars on the graph can tell a lot about what the changes in the birth and death rates of a particular area.

Interactive exercise. Assistance may be required. Roll over the three pyramids below to learn more.

Below are some items to look for when reading a population pyramid:

  • Width of the base- birth rate varies with the width of the base.
  • Symmetry- pyramids should be symmetrical. Any asymmetry indicates a difference in the male and female population.
  • Shape of sides- Concave sides (curving inward) indicate a high death rate and convex sides (bulging outward) indicate a low death rate.
  • Bumps in the sides- irregularities in the sides indicate a demographic anomaly.

 

The shape of population pyramids can provide a lot of information just by looking at it. Read the chart below which describes the various types of pyramids.

Interactive exercise. Assistance may be required. Click on the name of each type to see an example.

Name Shape Description What does it mean?
Expanding Classic pyramid/triangle Wide base(high birth rate) and narrow top (high death rate) An expanding pyramid represents a lower standard of living; High birth rate is due to lack of access to birth control/lack of education. High death rate is due to poor health care and nutrition.
Stable/Stationary 1/2 Elipse Base width is equal to the width of reproductive years' width Low birth rate because of good family planning and education; low death rate because of good healthcare and nutrition.
Contracting Pyramid contracts at the base. Sometimes called a beehive. The base is narrower than the reproductive ages. Low birthrate represents a well-developed country.