Sources of error and bias in methods of fertility estimation contingent on the P/F ratio in a time of declining fertility and rising mortality

Almost all commonly used indirect fertility estimation methods rely on the P/F ratio. As originally conceived, the ratio compares cumulated cohort fertility with cumulated period fertility on the basis of three, fairly strong, assumptions. The intention of this paper is to interrogate what happens to the results produced by the P/F ratio method as each of these three assumptions is violated, first independently, and then concurrently. These investigations are important given the generally poor quality of census data collected in developing countries, particularly sub-Saharan Africa, and the radically altering demographic conditions associated with a generalised HIV/AIDS epidemic in the region.