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	Total Fertility Rate	Net Reproduction Rate
分野	人口学	人口学
系統	Process / pipeline	Process / pipeline
提唱年	2001	2001
提唱者	Classical demographic index (formalized by Preston, Heuveline & Guillot)	Richard Böckh and Robert Kuczynski (formalized in Preston, Heuveline & Guillot)
種類	Period summary fertility index synthesizing age-specific fertility rates	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	TFR, Period total fertility rate, Sum of age-specific fertility rates, Toplam Doğurganlık Hızı	NRR, Net reproduction ratio, Net reproductive rate, Net Üreme Hızı
関連	4	4
概要	The total fertility rate (TFR) is the central period measure of fertility in demography: the average number of children a woman would bear over her lifetime if she experienced, at each age, the age-specific fertility rates observed in a given year. Computed by summing age-specific fertility rates across the reproductive ages, the TFR removes the influence of population age structure and gives a single, intuitive figure — children per woman — that is comparable across populations and over time.	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.