Singulate Mean Age at Marriage

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.