# Parity progression ratio

From Demography

## Definition

The term **parity progression ratio** (**PPR**) is typically used in the context of a cohort of females (such as a birth cohort) that has completed its childbearing years. Given such a cohort, and a nonnegative integer , the parity progression ratio from birth order to birth order is defined as the ratio of the completed cohort fertility for that cohort for birth order , to the completed cohort fertility for that cohort for birth order .

Alternatively, the PPR describes the probability that a person in that cohort who has had children will proceed to have an child.