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	Net Reproduction Rate	Mean Age at Childbearing
分野	人口学	人口学
系統	Process / pipeline	Process / pipeline
提唱年	2001	1968
提唱者	Richard Böckh and Robert Kuczynski (formalized in Preston, Heuveline & Guillot)	Standard demographic practice (fertility schedule moments)
種類	Period measure of generational replacement combining fertility and mortality	Summary location measure of the age pattern of fertility
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	NRR, Net reproduction ratio, Net reproductive rate, Net Üreme Hızı	MAC, Mean age of the fertility schedule, Mean age of mothers at birth, Ortalama Doğurganlık Yaşı
関連	4	4
概要	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.	The mean age at childbearing is the average age of mothers at the birth of their children, computed as the fertility-rate-weighted mean of maternal age over the age-specific fertility schedule. As the first moment of the fertility curve, it summarizes the tempo — the timing — of childbearing in a single number, complementing the total fertility rate, which measures quantum, or how many children are born.