Parity progression ratios
A parity progression ratios (PPR) is a measure commonly used in demography to study fertility. The PPR is simply the proportion of women with a certain number of children who go onto have another child. Calculating the PPR, also known as , can be achieved by using the following formula:
In more developed countries 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.
- Hinde, A (1998) "Demographic Methods", Hodder Arnold Publication.