Caught in Transit: Identifying Stalls, Upswings and Reversals in Fertility Transitions using a Probabilistic Approach

Possible stalls in fertility transitions, especially in sub-Saharan Africa, have been discussed frequently in the demography literature. However, the various methods used to identify stalls were limited by reliance on irregular inter-survey intervals, inconsistent definitions, and failure to account for measurement uncertainty. We propose a new probabilistic approach for identifying fertility transition stalls based on the results of the 2024 revision of World Population Prospects (United Nations, 2024a) and apply it to all countries for periods when total fertility is above 2.1 live births per woman. Our method is not restricted to inter-survey intervals; it uses all available data from all available data sources, incorporates biases and measurement errors, and provides probabilistic estimates of fertility stalls. We compared our findings for sub-Saharan Africa to those in the literature and found that the probability of many previously identified stalls is quite low based on the data available. We also identify several stalls (or reversals) in fertility decline across all regions since 1950 and discuss potential reasons for these changes in fertility trends.