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	Mean Age at Childbearing	Tempo-Adjusted Fertility
Field	Demography	Demography
Family	Process / pipeline	Process / pipeline
Year of origin	1968	1998
Originator	Standard demographic practice (fertility schedule moments)	John Bongaarts & Griffith Feeney
Type	Summary location measure of the age pattern of fertility	Tempo-and-quantum adjustment of the period total fertility rate
Seminal source	Preston, S. H., Heuveline, P., & Guillot, M. (2001). Demography: Measuring and Modeling Population Processes. Blackwell. ISBN: 9781557864512	Bongaarts, J., & Feeney, G. (1998). On the quantum and tempo of fertility. Population and Development Review, 24(2), 271–291.
Aliases	MAC, Mean age of the fertility schedule, Mean age of mothers at birth, Ortalama Doğurganlık Yaşı	Bongaarts-Feeney adjustment, Tempo-adjusted TFR, Quantum-tempo decomposition of fertility, Tempo Düzeltmeli Doğurganlık
Related	4	4
Summary	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.	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.