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	Population Pyramid Analysis	Net Reproduction Rate
分野	人口学	人口学
系統	Process / pipeline	Process / pipeline
提唱年	1874	2001
提唱者	Francis A. Walker (early age-sex diagrams); standard demographic practice	Richard Böckh and Robert Kuczynski (formalized in Preston, Heuveline & Guillot)
種類	Graphical and tabular analysis of population age-sex structure	Period measure of generational replacement combining fertility and mortality
原典	Preston, S. H., Heuveline, P., & Guillot, M. (2001). Demography: Measuring and Modeling Population Processes. Blackwell. ISBN: 9781557864512	Preston, S. H., Heuveline, P., & Guillot, M. (2001). Demography: Measuring and Modeling Population Processes. Blackwell. ISBN: 9781557864512
別名	Age-sex pyramid, Population age structure diagram, Age structure analysis, Nüfus Piramidi Analizi	NRR, Net reproduction ratio, Net reproductive rate, Net Üreme Hızı
関連	4	4
概要	Population pyramid analysis is the description and interpretation of a population's age-sex structure through a back-to-back horizontal bar chart, with males on one side, females on the other, and age groups stacked from youngest at the bottom to oldest at the top. The shape of the pyramid encodes a population's fertility, mortality, and migration history and is the demographer's first diagnostic of whether a population is young and growing, ageing, or contracting.	The net reproduction rate (NRR) is the demographic measure of generational replacement: the average number of daughters a woman would bear who survive to the age their mother was when she bore them, given the period's age-specific fertility rates and female mortality. By combining fertility with survival, the NRR answers the fundamental question of whether a population is replacing itself — an NRR of one means each generation of women exactly reproduces the next, below one signals long-run decline, and above one signals growth.