The future of low fertility: first results from a global survey of experts

Stuart A. Basten, University of Oxford
Tomas Sobotka, Vienna Institute of Demography
Bilal Barakat, Vienna Institute of Demography
Wolfgang Lutz, International Institute for Applied Systems Analysis (IIASA)

In Summer 2011 an Internet survey on the likely future trends in fertility, mortality, and migration and the main factors behind them has been conducted among the members of major population associations. The survey, organised as a collaboration of IIASA and Oxford University, will become a basis for new global probabilistic population forecasts by age, sex, and level of education. By allowing a large number of experts to participate and by providing an argument-based underpinning of numerical estimates about future fertility trends, the survey addresses two common weaknesses of population projection-making: 1) very limited or no theoretical foundation and 2) a participation of a small and often closed group of experts in formulating the parameters of projection scenarios. Our study presents first results of the survey module on low fertility, which focuses on countries that are relatively rich and have at present low fertility. The experts were offered 46 arguments potentially relevant for the future trends in fertility, and clustered into six groups of factors. They have selected a country or a group of countries, to which their assessment pertains, and also provided numerical estimates of the likely range of the period total fertility rates in 2030 and 2050. Altogether, 184 experts have assessed the low-fertility module of the survey. These experts represented 41 low-fertility countries on 6 continents. We cluster these countries into regions and analyse the responses along several key dimensions: numerical estimates of future period TFR, the relevance and impact of individual arguments, and the relative importance of the clusters of arguments. We pay special attention to the arguments where experts gave contrasting views about their likely importance and impact on fertility. These diverging views either indicate existence of region-specific factors, or they signal considerable disagreement about the likely impact of some factors on future fertility trends.