Download MORTPAK FOR WINDOWS - the United Nations

N. Description of PRESTO
Purpose of procedure
Provides integrated estimates of intercensal mortality, fertility and age distribution
based on recorded age distributions from two censuses and assumption of a United
Nations, Coale-Demeny or user-designated model life table pattern. Starting in version
4.3, new output tables were added to display q(15,45) and q(15,35) values.
Description of technique
Preston (1983) has demonstrated a simple method for estimating intercensal
mortality, fertility and age distributions in a closed population based on two recorded
census age distributions and assumption of a model life table pattern. The method is
referred to as the "integrated method" because it combines Brass's one-parameter logit
mortality system (Brass and others, 1968) with the generalized stable population equation
(Preston and Coale, 1982).
The one-parameter (α) Brass system relates a chosen model life table (referred to
as the standard) to any other life table within the same model life table system according
to the equation
where ps(a) is the probability of surviving to age a in the model life table, p(a) is the
corresponding value for any other life table within the same system, and α is a parameter.
The generalized stable population equation applies to any closed population and
relates the current age distribution to current levels of mortality, fertility and age-specific
growth rates. Namely,
where c(a) is the proportion of the population aged a, b is the crude birth rate, r(x) is the
growth rate of persons age x, and p(a) is the probability of survival to age a.
If we assume that p(a) in equation (1) describes the current life table for the population
described by equation (2), we can solve equation (1) for p(a), substitute into equation (2)
and after further manipulation,
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