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)

    “The true charm of pedestrianism does not lie in the walking, or in the scenery, but in the talking. The walking is good to time the movement of the tongue by, and to keep the blood and the brain stirred up and active; the scenery and the woodsy smells are good to bear in upon a man an unconscious and unobtrusive charm and solace to eye and soul and sense; but the supreme pleasure comes from the talk.”
    —Mark Twain [Samuel Langhorne Clemens] (1835–1910)