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	Singulate Mean Age at Marriage	Total Fertility Rate
Field	Demography	Demography
Family	Process / pipeline	Process / pipeline
Year of origin	1953	2001
Originator	John Hajnal	Classical demographic index (formalized by Preston, Heuveline & Guillot)
Type	Indirect estimate of mean age at first marriage from census proportions	Period summary fertility index synthesizing age-specific fertility rates
Seminal source	Hajnal, J. (1953). Age at marriage and proportions marrying. Population Studies, 7(2), 111–136.	Preston, S. H., Heuveline, P., & Guillot, M. (2001). Demography: Measuring and Modeling Population Processes. Blackwell. ISBN: 9781557864512
Aliases	SMAM, Hajnal's Mean Age at Marriage, Singulate Mean Age at First Marriage	TFR, Period total fertility rate, Sum of age-specific fertility rates, Toplam Doğurganlık Hızı
Related	4	4
Summary	The singulate mean age at marriage (SMAM) is an indirect demographic estimate of the average age at first marriage, computed entirely from the proportions of people who have never married by age, as recorded in a single census or survey. Introduced by John Hajnal in 1953, it sidesteps the need for registered marriage dates: by treating the never-married proportions as a synthetic-cohort survival curve in the single state, it recovers the mean number of years lived single before first marriage among those who eventually marry.	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.