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:

    Against my will, I became a witness to the most terrible defeat of reason and to the most savage triumph of brutality ever chronicled ... never before did a generation suffer such a moral setback after it had attained such intellectual heights.
    Stefan Zweig (18811942)

    Easily, with a few convulsive quirks, they give up their watery ghosts, like a mortal translated before his time to the thin air of heaven.
    Henry David Thoreau (1817–1862)