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'{{Short description|Graphical illustration showing distribution of age groups in a population}} [[File:Angola population pyramid 2005.svg|upright=1.5|right|thumb|Population distribution by age and sex for Angola in 2005]] A '''population pyramid''' (age structure diagram) or "'''age-sex pyramid'''"<!--"age-sex pyramid" is about 40 times more common than "age-gender pyramid"--> is a graphical illustration of the distribution of a [[population]] (typically that of a country or region of the world) by age groups and sex; it typically takes the shape of a [[pyramid]] when the population is growing.<ref>{{cite web|url=http://populationpyramid.net/|title=Population Pyramids of the World from 1950 to 2100|website=PopulationPyramid.net|access-date=21 April 2018}}</ref> Males are usually shown on the left and females on the right, and they may be measured in absolute numbers or as a percentage of the total population. The pyramid can be used to visualize the age of a particular population.<ref>{{Cite book|title=Population An introduction to concepts and issues|last=Weeks|first=John|publisher=Wadsworth|year=2001|pages=307}}</ref> It is also used in ecology to determine the overall age distribution of a population; an indication of the reproductive capabilities and likelihood of the continuation of a species. Number of people per unit area of land is called [[population density]]. ==Structure== {{More citations needed section|date=September 2018}} A population pyramid often contains continuous [[bar chart|stacked-histogram bars]], making it a horizontal bar diagram. The population size is shown on the x-axis (horizontal) while the age-groups are represented on the y-axis (vertical).<ref>{{Cite encyclopedia|url=https://www.britannica.com/topic/population-pyramid|title=population pyramid {{!}} sociology|encyclopedia=Encyclopædia Britannica|access-date=2017-03-29|language=en}}</ref> The size of each bar can be displayed either as a [[percent]]age of the total population or as a raw number. Males are conventionally shown on the left and females on the right. Population pyramids are often viewed as the most effective way to graphically depict the age and distribution of a population, partly because of the very clear image these pyramids provide.<ref>[http://www.health.state.pa.us/hpa/stats/techassist/pyramids.htm Department of Health Home<!-- Bot generated title -->] {{webarchive|url=https://web.archive.org/web/20090830154203/http://www.health.state.pa.us/hpa/stats/techassist/pyramids.htm |date=2009-08-30 }}</ref> 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 [[Sustainable development|extent of development]] and other aspects of the population. The measures of central tendency ([[Arithmetic_mean|mean]], [[median]], and [[Mode_(statistics)|mode]]) should be considered when assessing a population pyramid. For example, the average age could be used to determine the type of population in a particular region. A population with an average age of 15 would be very young compared to one with an average age of 55. Population statistics are often mid-year numbers. A series of population pyramids could give a clear picture of how a country transitions from high to low [[fertility rate]]s. If the pyramid has a broad base, this indicates that a relatively high proportion of the population lies in the youngest age band, such as ages 0–14, which suggests that the fertility rate of the country is high and above [[sub-replacement fertility|replacement fertility]] level.<ref>{{Cite web|url=http://www.prb.org/Publications/Articles/2013/population-pyramids.aspx|title=From Population Pyramids to Pillars|website=www.prb.org|access-date=2017-03-29}}</ref> If a population is below replacement fertility level, the older population is declining with age, due to a combination of mortality and an increase in the number of births over time. There are usually more females than males in the older age ranges since, for a variety of reasons, women have a greater life expectancy. The shape of the pyramid can also reveal the age-dependency ratio of a population. Populations with a high proportion of children and/or of elderly people have a higher [[dependency ratio]]. This ratio refers to how many old and young people are dependent on the working-age groups (often defined as ages 15–64). According to Weeks' ''Population: an Introduction to Concepts and Issues,'' population pyramids can be used to predict the future, known as a population forecast. [[Population momentum]], when a population's birth rates continue to increase even after fertility rate has declined to replacement level, can even be predicted if a population has a low mortality rate since the population will continue to grow. This then brings up the term [[doubling time]], which is used to predict when the population will double in size. Lastly, a population pyramid can even give insight into the economic status of a country from the [[age stratification]] since the distribution of supplies is not evenly distributed through a population. == Demographic transition == {{multiple image | height = 200 | footer = | image1 = Switzerland population pyramid in 1900.svg | width1 = 200 | caption1 = 1900 | image2 = Switzerland population pyramid in 2000.svg | width2 = 200 | caption2 = 2000 | image3 = Switzerland population pyramid in 2100.svg | width3 = 200 | caption3 = 2100 | header = The development and transition of Switzerland's population pyramid over 2 centuries }} In the [[demographic transition]] model, the size and shape of population pyramids vary. In stage one of the demographic transition model, the pyramids have the most defined shape. They have the ideal big base and a skinny top. In stage two, the pyramid looks similar but starts to widen in the middle age groups. In stage three, the pyramids start to round out and look similar in shape to a tombstone. In stage four, there is a decrease in the younger age groups. This causes the base of the widened pyramid to narrow. Lastly, in stage five, the pyramid starts to take on the shape of a kite as the base continues to decrease. The shape of the population is dependent upon what the economy is like in the country. More developed countries can be found in stages three, four, and five, while the [[least developed countries]] have a population represented by the pyramids in stages one and two. ==Types== [[File:Nigeria single age population pyramid 2020.png|thumb|Population age pyramid of [[Demographics of Nigeria|Nigeria]] in 2020, similar to all of sub-Saharan Africa]] Each country will have a different population pyramid. However, population pyramids can be categorised into three types: stationary, expansive, or constrictive. These types have been identified by the fertility and mortality rates of a country.<ref name=osu>[http://www.fsl.orst.edu/pnwerc/wrb/Atlas_web_compressed/5.Human_Populations/5h.pyramids_web.pdf Population Pyramids] - Oregon State University</ref> ;"Stationary" pyramid or constant population pyramid :A pyramid can be described as stationary if the percentages of population (age and sex) remain approximately constant over time.<ref name=":0">{{Cite book|title=Population An Introduction to concepts and issues|last=Weeks|first=John|publisher=Wadsworth|year=2011|isbn=978-1305094505|pages=309}}</ref> In a stationary population, the numbers of births and death roughly balance one another. ;"Expansive" pyramid or Expanding population pyramid :A population pyramid that is very wide at the younger ages, characteristic of countries with a high birth rate and perhaps low life expectancy therefore leading to high death rate.<ref name=osu/> The population is said to be fast-growing, and the size of each birth cohort increases each year. <ref name=":1">{{Cite journal|last=Korenjak-Cˇ erne, Kejžar, Batagelj|year=2008|title=Clustering of Population Pyramids|journal=Informatica|volume=32}}</ref> ;"Constrictive" pyramid or Declining population :A population pyramid that is narrowed at the bottom. The population is generally older on average, as the country has long life expectancy, a low death rate, but also a low birth rate.<ref name=osu/> This may suggest that in future there may be a high dependency ratio due to reducing numbers at working ages. This is a typical pattern for a very developed country, with a high level of education, easy access to and incentive to use birth control, good health care, and few negative environmental factors.<ref>{{Cite web|url=https://www.populationeducation.org/content/what-are-different-types-population-pyramids|title=What are the different types of population pyramids?|last=Boucher|first=Lauren|date=10 March 2016|website=www.populationeducation.org |access-date=29 March 2017}}</ref> <gallery> File:Afghanistan single age population pyramid 2020.png|Population pyramid of [[Demographics of Afghanistan|Afghanistan]] (Expansive) File:Ecuador single age population pyramid 2020.png|Population pyramid of [[Demographics of Ecuador|Ecuador]] (Stationary) File:Italy Population Pyramid.svg|Population pyramid of [[Demographics of Italy|Italy]] (Constrictive) File:Qatar single age population pyramid 2020.png|Population pyramid of [[Demographics of Qatar|Qatar]] (Unbalanced) </gallery> ==Youth bulge== {{See also|Baby boom|List of countries by median age}} [[File:2017 world map, median age by country.svg|thumb|300px|[[Median]] age by country. A youth bulge is evident for [[Demographics of Africa|Africa]], and to a lesser extent for West Asia, South Asia, Southeast Asia and Central America.]] [[File:Total Fertility Rate Map by Country.svg|thumb|right|upright=1.35|Map of countries by fertility rate ({{CURRENTYEAR}}), according to the [[Population Reference Bureau]]]] Gary Fuller (1995) described a youth bulge as a type of expansive pyramid. [[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. 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 [[genocide]]s can be readily explained as a result of a built-up youth bulge.<ref>{{Cite news|url=http://www.washingtonexaminer.com/article/2615183|title=Why a two-state solution doesn't guarantee peace in the Middle East|work=Washington Examiner|access-date=2017-04-05}}</ref> This factor has been also used to account for the [[Arab Spring]] events and the rise of extremist [[populism]] in the 2010s.<ref name="cliodynamics.ru">[[Andrey Korotayev|Korotayev A.]] et al.[http://cliodynamics.ru/index.php?option=com_content&task=view&id=309&Itemid=1 A Trap At The Escape From The Trap? Demographic-Structural Factors of Political Instability in Modern Africa and West Asia. ''Cliodynamics'' 2/2 (2011): 1-28].</ref> [[Economic recession]]s, such as the [[Great Depression]] of the 1930s and the late 2000s [[Great Recession]], are also claimed to be explained in part due to a large youth population who cannot find jobs.<ref name="cliodynamics.ru"/> Youth bulge can be seen as one factor among many in explaining social unrest and uprisings in society.<ref name="cfr.org">{{cite web|url=http://www.cfr.org/society-and-culture/effects-youth-bulge-civil-conflicts/p13093|title=The Effects of 'Youth Bulge' on Civil Conflicts|access-date=21 April 2018|archive-url=https://web.archive.org/web/20130527020909/http://www.cfr.org/society-and-culture/effects-youth-bulge-civil-conflicts/p13093|archive-date=27 May 2013|url-status=dead}}</ref> A 2016 study finds that youth bulges increase the chances of non-ethnic civil wars, but not ethnic civil wars.<ref>{{Cite journal|title = Youth bulge and civil war: Why a country's share of young adults explains only non-ethnic wars|journal = Conflict Management and Peace Science|date = 2016-02-01|issn = 0738-8942|pages = 25–44|volume = 33|issue = 1|doi = 10.1177/0738894214544613|language = en|first1 = Omer|last1 = Yair|first2 = Dan|last2 = Miodownik|s2cid = 144349983}}</ref> A large population of adolescents entering the labor force and electorate strains at the seams of the economy and polity, which were designed for smaller populations. This creates unemployment and alienation unless new opportunities are created quickly enough&nbsp;– in which case a 'demographic dividend' accrues because productive workers outweigh young and elderly dependents. Yet the 16–29 age range is associated with risk-taking, especially among males. In general, youth bulges in developing countries are associated with higher unemployment and, as a result, a heightened risk of violence and [[political instability]].<ref>Huntington, Samuel P. 1996. The Clash of Civilizations and the Remaking of World Order. New York, NY: Simon and Schuster</ref><ref>[[Henrik Urdal|Urdal, Henrik]]. 2006. "A Clash of Generations? Youth Bulges and Political Violence." International Studies Quarterly 50:607-29 {{doi|10.1111/j.1468-2478.2006.00416.x}}</ref> For Cincotta and Doces (2011), the transition to more mature age structures is almost a [[sine qua non]] for democratization.<ref>Cincotta, Richard, and John Doces. 2011. "The Age-structural Maturity Thesis: The Youth Bulge's Influence on the Advent and Stability of Liberal Democracy?" In [http://www.paradigmpublishers.com/books/BookDetail.aspx?productID=280257 Political Demography: identity, conflict and institutions ed. J. A. Goldstone, E. Kaufmann and M. Toft. Boulder, CO: Paradigm Press] {{Webarchive|url=https://web.archive.org/web/20170226182539/http://www.paradigmpublishers.com/books/BookDetail.aspx?productID=280257 |date=2017-02-26 }}</ref> To reverse the effects of youth bulges, specific policies such as creating more jobs, improving family planning programs, and reducing over all infant mortality rates should be a priority.<ref>{{Cite news|url=http://www.cfr.org/world/effects-youth-bulge-civil-conflicts/p13093|title=The Effects of 'Youth Bulge' on Civil Conflicts|work=Council on Foreign Relations|access-date=2017-04-05|language=en}}</ref> ===Middle East and North Africa=== {{Further|Demographic trap}} [[File:Egypt population pyramid 2005.svg|thumb|Population pyramid of [[Demographics of Egypt|Egypt]] in 2005. Many of those 30 and younger are educated citizens who are experiencing difficulty finding work.]] [[File:LibyaPopulation2011.jpg|thumb|Nearly half of [[Demographics of Libya|Libya]]'s 2011 population consists of people younger than age 20.]] The [[Middle East]] and [[North Africa]] are currently experiencing a prominent youth bulge. "Across the Middle East, countries have experienced a pronounced increase in the size of their youth populations over recent decades, both in total numbers and as a percentage of the total population. Today, the nearly 111 million individuals aging between 15 to 29 living across the region make up nearly 27 percent of the region's population."<ref name="Hassan and Dyer">{{cite journal|last1=Hassan|first1=Islam|last2=Dyer|first2=Paul|title=The State of Middle Eastern Youth.|journal=The Muslim World|date= 2017|volume=107|issue=1|pages=3–12|doi=10.1111/muwo.12175|url=https://repository.library.georgetown.edu/bitstream/handle/10822/1042998/TheMuslimWorld_CIRS_Special_Issue_Intro_January2017.pdf?sequence=1}}</ref> Structural changes in service provision, especially health care, beginning in the 1960s created the conditions for a demographic 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 25.<ref>{{cite web|url=http://www.shababinclusion.org/content/blog/detail/986/|title=Middle East Youth Initiative|website=Middle East Youth Initiative|access-date=21 April 2018}}</ref> The youth bulge in the Middle East and North Africa has been favorably compared to that of East Asia, which harnessed this human capital and saw huge economic growth in recent decades.<ref>{{cite web|title=Youth – An Undervalued Asset: Towards a New Agenda in the Middle East and North Africa, Progress, Challenges and Way Forward," Middle East and North Africa Region Human Development Department (MNSHD), The World Bank, 2007|url=http://www.childmigration.net/files/433720SR0WHITE11PUBLIC10YPN1English.pdf|access-date=27 October 2011|archive-url=https://web.archive.org/web/20120119014914/http://www.childmigration.net/files/433720SR0WHITE11PUBLIC10YPN1English.pdf|archive-date=19 January 2012|url-status=dead}}</ref> 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.<ref>{{cite web|title=Middle East Youth Initiative: About: Why Shabab?|url=http://www.shababinclusion.org/section/about/why_shabab|access-date=27 October 2011}}</ref> "While the growth of the youth population imposes supply pressures on education systems and labor markets, it also means that a growing share of the overall population is made up of those considered to be of working age; and thus not dependent on the economic activity of others. In turn, this declining dependency ratio can have a positive impact on overall economic growth, creating a demographic dividend. The ability of a particular economy to harness this dividend, however, is dependent on its ability to ensure the deployment of this growing working-age population towards productive economic activity, and to create the jobs necessary for the growing labor force."<ref name="Hassan and Dyer" /> ==See also== {{div col|colwidth=22em}} * [[Age class structure]] * [[Demographic analysis]] * [[Demographic transition]] * [[Middle East Youth Initiative]] * [[Human overpopulation|Overpopulation]] * [[Political demography]] * [[Population growth]] * [[Human sex ratio|Sex ratio]] * [[Waithood]] {{div col end}} ==References== === Citations === {{Reflist}} ===Additional references=== * U.S. Census Bureau, Demographic Internet Staff (June 27, 2011). [https://www.census.gov/data-tools/demo/idb/informationGateway.php "International Programs, International Data Base"]. Information Gateway. U.S. Census Bureau. * [http://www.prb.org/data/ "Population Reference Bureau – Inform, Empower, Advance"]. Population Reference Bureau. * [http://www.un.org/en/databases/index.html "Databases"]. United Nations. * Zarulli, Virginia, et al. [http://www.pnas.org/content/early/2018/01/03/1701535115 "Women Live Longer than Men Even During Severe Famines and Epidemics"]. ''Proceedings of the National Academy of Sciences'', National Academy of Sciences, Jan 3 2018. ==External links== {{Commons category|Population pyramids}} * [https://web.archive.org/web/20150508162816/http://esa.un.org/unpd/wpp/Demographic-Profiles/index.shtm World Population Prospects, the 2010 Revision], Website of the United Nations Population Division with population pyramids for all countries * [https://www.census.gov/programs-surveys/international-programs/about/related-sites.html U.S. Census Bureau, International Statistical Agencies] * [https://www.census.gov/data-tools/demo/idb/informationGateway.php U.S. Census Bureau, International Database (IDB)] * [http://www.abs.gov.au/websitedbs/d3310114.nsf/home/population%20pyramid%20preview Australian animated population pyramids, Australian Bureau of Statistics] * [http://www.insee.fr/fr/ppp/bases-de-donnees/irweb/projpop0760/dd/pyramide/pyramide.htm Interactive population pyramids of metropolitan France 1901-2060 (INSEE)] {{Population}} {{Authority control}} {{DEFAULTSORT:Population Pyramid}} [[Category:Demographic economics]] [[Category:Ageing]] [[Category:Demographics]] [[Category:Demography]] [[Category:Population geography]] [[Category:Statistical charts and diagrams]]'