Stable populations based on a life table and assumed growth rate

Stationary populations (revision)

See PAPP101_S08 for an overview of a stationary population.

Stationary populations are the simplest form of stable populations. Age-specific fertility and mortality rates are constant, and their net effects "cancel out" – that is, for a given period there will always be equal numbers of births and deaths. A life table represents a stationary population in which the _nL_x life table function is equivalent to the population in the age group x to x+n.

The age-specific fertility rates that generate this stationary life table population are not usually specified in practice, but it is assumed that they result in an annual number of births that is equal to the radix of the life table. The size of a stationary population will, by definition, always be the same, and the crude birth and death rates will never change and will always be equal.

In a stationary population, the proportion in each age group is constant as in any stable population, but unlike a growing or shrinking stable population, the numbers in each age group are also constant over time.