Population pyramid

This distribution is named for the pyramidal shape of its graph.

A population pyramid, also called age-sex pyramid and age structure diagram, is a graphical illustration that shows the distribution of various age groups in a human population (typically that of a country or region of the world), which normally forms the shape of a pyramid.

It typically consists of two back-to-back bar graphs, with the population plotted on the X-axis and age on the Y-axis, one showing the number of males and one showing females in a particular population in five-year age groups (also called cohorts). Males are conventionally shown on the left and females on the right, and they may be measured by raw number or as a percentage of the total population.

Population pyramids are often viewed as the most effective way to graphically depict the age and sex distribution of a population, partly because of the very clear image these pyramids present.^[1]

A great deal of information about the population broken down by age and sex can be read from a population pyramid, and this can shed light on the extent of development and other aspects of the population. A population pyramid also tells how many people of each age range live in the area. There tends to be more females than males in the older age groups, due to females' longer life expectancy.

A helpful analogy to facilitate understanding population pyramids is that just as a builder employs a blueprint for showing a house's structure, demographers and geographers employ population pyramids as a blueprint for showing population dynamics.^[2]

Types of population pyramid

Population pyramids for 4 stages of the demographic transition model

While all countries' population pyramids differ, four types have been identified by the fertility and mortality rates of a country.

Stable pyramid - A population pyramid showing an unchanging pattern of fertility and mortality.

Stationary pyramid - A population pyramid typical of countries with low fertility and low mortality, also called a constrictive pyramid.

Expansive pyramid - A population pyramid showing a broad base, indicating a high proportion of children, a rapid rate of population growth, and a low proportion of older people. This wide base indicates a large number of children. A steady upwards narrowing shows that more people die at each higher age band. This type of pyramid indicates a population in which there is a high birth rate, a high death rate and a short life expectancy. This is the typical pattern for less economically developed countries, due to little access to and incentive to use birth control, negative environmental factors (for example, lack of clean water) and poor access to health care.

Constrictive pyramid - A population pyramid showing lower numbers or percentages of younger people. The country will have a greying population which means that people are generally older.

Young and ageing populations

Generally a population pyramid that displays a population percentage of ages 1–14 over 30% and ages 75 and above under 6% is considered a "young population" (generally occurring in developing countries, with a high agricultural workforce). A population pyramid that displays a population percentage of ages 1–14 under 30% and ages 75 and above over 6% is considered an "aging population" (that of which generally occurs in developed countries with adequate health services, e.g. Australia). A country that displays all or none of these characteristics is considered neither.

Youth bulge

Median age by country. A youth bulge is evident for Africa, and to a lesser extent for South and Southeast Asia and Central America.

A world map showing countries by fertility rate, 2005-2010.

7-8 Children      6-7 Children      5-6 Children      4-5 Children

3-4 Children      2-3 Children      1-2 Children      0-1 Children

The expansive case was described as youth bulge by Gary Fuller (1995). Gunnar Heinsohn (2003) argues that an excess in especially young adult male population predictably leads to social unrest, war and terrorism, as the "third and fourth sons" that find no prestigious positions in their existing societies rationalize their impetus to compete by religion or political ideology. However this claim is disputed as many historical instances of social unrest related to young adult male populations are usually caused by a shortage of women for marriage.

Heinsohn claims that most historical periods of social unrest lacking external triggers (such as rapid climatic changes or other catastrophic changes of the environment) and most genocides can be readily explained as a result of a built-up youth bulge, including European colonialism, 20th-century fascism, rise of Communism during the Cold War, and ongoing conflicts such as that in Darfur and terrorism. Historical economic recessions; such as the Great Depression of the 1930's, are also claimed to be explained in part due to a large youth population who cannot find jobs.

One problem with this line of reasoning is that under conditions prevailing before the introduction of modern medicine, death rates were much higher than they are now, and almost all societies had youth bulges even when their population growth rate was negligible. However, they certainly did not experience such youth bulge as prevails today in some parts of the world or as prevailed in twentieth century Germany or in Africa and the Middle East nowadays.

It is not just that most periods of unrest occurred in societies with youth bulges, but that some of the pre-modern periods of any sort existed in societies with such bulges as well. Nevertheless, since the improvement of medicine and its introduction, the element of youth bulge has become far more salient than before. Therefore, perhaps it cannot explain massacres throughout human history, but it can serve as rather plausible theory to explain the terror, social unrest, and uprisings in today's society.

Another problem is that it ignores the social consequences of poverty, corruption and mass unemployment among young males in developing countries, where most of the world's current population growth is occurring. The "youth bulge" is not an accurate predictor of social unrest, war and terrorism, because they are the product of far more complicated and interrelated set of factors, of which demographics only plays a part. Yet, even when there are other factors and circumstance to enable mass unrest, a youth bulge is likely to be one of them.

Youth bulge theory represents one of the most recently developed theories of war and social unrest, and has become highly influential on U.S. foreign policy as two major U.S. proponents of the theory, U.S. political scientist Jack Goldstone^[3] and U.S. political scientist Gary Fuller,^[4] have acted as consultants to the U.S. government.

Afghanistan shows a classic youth bulge.

Angola shows the same, even more pronounced.

China had an extreme youth bulge until the 1960s, when it sharply curbed partly as an effect of the one-child policy.

Compare the population pyramid of the USA which was bulging until the 1960s and has steadily slimmed since.

Middle East and North Africa

The Middle East and North Africa are currently experiencing a prominent youth bulge. Structural changes in service provision, especially health care, beginning in the 1960s created the conditions for a population explosion, which has resulted in a population consisting primarily of younger people. It is estimated that around 65% of the regional population is under the age of 30.^[5]

The Middle East has invested more in education, including religious education, than most other regions such that education is available to most young people.^[6] However, that education has not led to higher levels of employment, and youth unemployment is currently at 25%, the highest of any single region^[7]. Of this 25%, over half are first time entrants into the job market.^[8]

The youth bulge in the Middle East and North Africa has been favorably compared to that of the Asian Tigers, which harnessed this human capital and saw huge economic growth in recent decades.^[9] The youth bulge has been referred to by the Middle East Youth Initiative as a demographic gift, which, if engaged, could fuel regional economic growth and development.

Uses of population pyramids

Population pyramids can be used to find the number of economic dependents being supported in a particular population. Economic dependents are defined as those under 15 (children who are in full time education and therefore unable to work) and those over 65 (those who have the option of being retired). In some less developed countries children start work well before the age of 15, and in some developed countries it is common to not start work until 30 (like in the North European countries), and people may work beyond the age of 65, or retire early. Therefore, the definition provides an approximation. In many countries, the government plans the economy in such a way that the working population can support these dependents. This number can be further used to calculate the dependency ratio in that population.

Population pyramids can be used to observe the natural increase, birth, and death rate.

See also

• Age class structure
• Baby boom
• Demographic transition
• Gender imbalance
• Sex-selective abortion and infanticide
• Population
• Population growth
• Demographic analysis
• Middle East Youth Initiative
• Waithood
• List of countries by median age

References

Other references

• Gary Fuller, "The Youth Crisis in Middle Eastern Society" (2004) download
• Gary Fuller, The Demographic Backdrop to Ethnic Conflict: A Geographic Overview, was born in 1989 and was produced by Edward Gewin: The Challenge of Ethnic Conflict to National and International Order in the 1990s, Washington: CIA (RTT 95-10039, October), 151-154.

External links

• Creating a population pyramid online.
• Navtej Dhillon, "Middle East Youth Bulge: Challenge or Opportunity?" (2008) The Brookings Institution
• "From Oil Boom to Youth Boon: Tapping the Middle East Demographic Gift" (2008) The Brookings Institution
• Graham Fuller, "The Youth Factor: The New Demographics of the Middle East and the Implications for U.S. Policy" (2003) The Brookings Institution
• Population Pyramids for 228 countries at the U.S. Census Bureau
• Canadian site with animations for different types of pyramids
• Australian animated population pyramids, Australian Bureau of Statistics
• China, Europe, USA: Population by Age and Sex, 1950-2050. Moving Age Pyramids.
• U.S. Census Bureau, Population Pyramids for Countries of the World
• The Security Demographic: Population and Civil Conflict after the Cold War
• The "Youth Bulge" (zmag.org)
• Creating a population pyramid with Excel.
• The Shape of Things to Come, Why Age Structure Matters To A Safer, More Equitable World
• Population age structure from the US Census Bureau in an interactive Excel dashboard
• Animation: a different approach to population pyramids using Excel
• A discussion on population pyramids as a data visualization tool