Is the fertility transition also a ‘phase transition’? A closer look at historical evidence from the U.S. and Ireland

Paul A. David, Stanford University
Warren C. Sanderson, International Institute for Applied System Analysis

We propose to investigate the hypothesis the forces that resulted eventually in a widespread and readily observable reduction of completed marital fertility produced discernable systematic changes in ‘pre-transitional’ fertility behaviour. This view, if supported, would offer an alternative to the two familiar (and conflicting) assertions regarding the onset of historical fertility transitions: (1) the Himes [1936/1970]–MacLaren [1990] view that fertility control methods were known since Biblical times and were used only ineffectually and episodically before the 19th century; (2) Coale’s contention that fertility regulation was not within the calculus of conscious choice of pre-transition populations characterised by “natural fertility.” Using the methodology of Cohort Parity Analysis (CPA) in conjunction with Barrett’s microsimulation model of natural fertility behaviour, the paper examines early 20th century census data from the U.S. and Ireland for indications of the joint evolution of fertility regulation and alterations in the fertility of the “non-controllers.”