An alternative stochastic framework for estimating pure measures of fertility

A stochastic fertility model is developed that incorporates a state of "viable pregnancy" within parity i. This model is used as a framework to derive formulas expressing relationships between various central rates and probabilities within parity i. Specifically, formulas are derived to relate the total fertility rate with the parity progression probability, a pregnancy rate with a pregnancy progression probability, and a direct fertility rate with a direct parity progression probability.