How do demographic trends change? The onset of birth masculinization in Albania, Georgia, and Vietnam 1990–2005

The theory of demographic transistion assumes the gradual move from a pre-transitional equilibrium of birth and death rates to a new equilibrium corresponding to lower vital rates. While this model remains largely correct,research on more than two centuries of demographic change has pointed to a signifcant number of variants and departures from the model. For instance, the secular decline in vital rates was often preceded by a short-term rise, starting from different high-fertility levels (Dyson and Murphy1985), and was at times followed by unexpected stalls and rebounds as in post war Europe (Van Bavel and Reher 2013), Southeast Asia (Hull 2012),sub-Saharan Africa (Shapiro and Gebreselassie 2013), and Central Asia(Spoorenberg 2015).