Fertility decline as a national, unitary phenomenon: the interwar intellectual inheritance

Since the end of the Second World War virtually all social scientific and historical research into large-scale change in fertility behaviour has been strongly influenced by the ‘theory’, or idea, of demographic transition. The seminal statement is considered to have been published in 1945, the product of the collective efforts of the group of social scientists who had spent much of the war producing strategic population projections for the US State Department, working under the leadership of F. W. Notestein at the Princeton Office of Population Research.

The original theory of demographic transition posited a general historical model, purporting to explain the course of any nations's changing demographic history during industrialisation. Reduced to its essentials, the model envisaged a three-stage process. In an initial pre-industrial era, high rates of gross fertility were more or less cancelled out by equally high rates of mortality. This was a ‘high pressure’ equilibrium exhibiting little secular trend of population growth or decline. A subsequent period of industrialisation and sustained economic growth then effected a period of transition – the second stage – to a new post-industrial ‘low pressure’ equilibrium. Rapid population growth typically occurred during the transition, or second stage, which normally lasted for several decades, as mortality rates fell more rapidly than fertility rates. In the third and final stage relatively low mortality rates would be offset by low fertility rates, once again resulting in population stasis.