Parity Progression Ratio

A parity progression ratio is the conditional probability that a woman who has already had a given number of children goes on to have one more. By converting a static parity distribution into a sequence of birth-by-birth transition probabilities, the method reveals where childbearing stops within a cohort and lets demographers rebuild completed fertility from the bottom up. It is the natural fertility analogue of a survival or life-table transition, treating each additional birth as a further step a woman may or may not take.