Generation Time

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

T = \frac{\sum_{x=\alpha}^{\omega} x l(x) m(x) }{\sum_{x=\alpha}^{\omega} l(x) m(x) }

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:

T = \sum_{x=\alpha}^{\omega} x e^{-rx} l(x) m(x)

where is the Malthusian parameter of the population.

Famous quotes containing the words generation and/or time:

    “Man is distinguished, not only by his reason; but also by this singular passion from other animals ... which is a lust of the mind, that by a perseverance of delight in the continual and indefatigable generation of knowledge, exceeds the short vehemence of any carnal pleasure.”
    —Thomas Hobbes (1588–1679)

    “Huck was always willing to take a hand in any enterprise that offered entertainment and required no capital, for he had a troublesome superabundance of that sort of time which is not money.”
    —Mark Twain [Samuel Langhorne Clemens] (1835–1910)