Generation time is a quantity used in population biology and demography to reflect the relative size of intervals of offspring production. Generation time usually expresses the average age of breeding females within a population. In epidemiology, it is defined as the interval of time between receipt of infection by a host and maximal infectivity of that host. Suppose females begin breeding at age and stop breeding (or die) at age, then the average age of first reproduction of a cohort of females is
where is the hazard function and is the fecundity of females aged .
When the population is in stable age distribution, we can express the generation time as the average age of mothers of zero-year-olds:
where is the Malthusian parameter of the population.
Famous quotes containing the words generation and/or time:
“Where do whites fit in the New Africa? Nowhere, I’m inclined to say ... and I do believe that it is true that even the gentlest and most westernised Africans would like the emotional idea of the continent entirely without the complication of the presence of the white man for a generation or two. But nowhere, as an answer for us whites, is in the same category as remarks like What’s the use of living? in the face of the threat of atomic radiation. We are living; we are in Africa.”
—Nadine Gordimer (b. 1923)
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Never in seventy years be more a man
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—Philip Larkin (1922–1986)