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	Tempo-Adjusted Fertility	Net Reproduction Rate
Field	Demography	Demography
Family	Process / pipeline	Process / pipeline
Year of origin	1998	2001
Originator	John Bongaarts & Griffith Feeney	Richard Böckh and Robert Kuczynski (formalized in Preston, Heuveline & Guillot)
Type	Tempo-and-quantum adjustment of the period total fertility rate	Period measure of generational replacement combining fertility and mortality
Seminal source	Bongaarts, J., & Feeney, G. (1998). On the quantum and tempo of fertility. Population and Development Review, 24(2), 271–291.	Preston, S. H., Heuveline, P., & Guillot, M. (2001). Demography: Measuring and Modeling Population Processes. Blackwell. ISBN: 9781557864512
Aliases	Bongaarts-Feeney adjustment, Tempo-adjusted TFR, Quantum-tempo decomposition of fertility, Tempo Düzeltmeli Doğurganlık	NRR, Net reproduction ratio, Net reproductive rate, Net Üreme Hızı
Related	4	4
Summary	Tempo-adjusted fertility is the Bongaarts-Feeney correction of the period total fertility rate that removes the distortion introduced when the timing of childbearing changes. When women collectively postpone (or advance) births, the conventional period total fertility rate is artificially depressed (or inflated) even if the number of children women ultimately have is unchanged; the adjustment inflates each birth-order-specific rate by a factor based on the changing mean age at childbearing to recover an undistorted measure of fertility quantum.	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.