A parity progression ratios (PPR) is a measure commonly used in demography to study
fertility
Fertility is the capability to produce offspring through reproduction following the onset of sexual maturity. The fertility rate is the average number of children born by a female during her lifetime and is quantified demographically. Ferti ...
. The PPR is simply the
proportion of women with a certain number of children who go on to have another child.
Calculating the PPR, also known as
, can be achieved by using the following
formula
In science, a formula is a concise way of expressing information symbolically, as in a mathematical formula or a ''chemical formula''. The informal use of the term ''formula'' in science refers to the general construct of a relationship betwe ...
:
[Hinde, A (1998) "Demographic Methods", Hodder Arnold Publication.]
In more
developed countries
A developed country (or industrialized country, high-income country, more economically developed country (MEDC), advanced country) is a sovereign state that has a high quality of life, developed economy and advanced technological infrastruct ...
where two-child families are seen as the norm
(or the proportion of women with two children who go on to have a third) is of critical importance in determining overall fertility levels.
is simply the proportion of women who become mothers.
References
{{Reflist
Human pregnancy