Background: Fertility decline in sub-Saharan Africa has been slower than in other regions, with the periods of extremely slow transitions frequently described as stalled. Lack of investment in family planning programs has been proposed as a key contributing factor. However, while there is a large literature on fertility transition stalls, similar phenomena in contraceptive prevalence trends have received less attention. Objective: We propose a probabilistic method for detecting plateaus in modern contraceptive prevalence (MCP) and in demand for family planning satisfied by modern methods (DS). Methods: We defined a contraceptive prevalence plateau in terms of level, rate, and probability conditions, each with associated thresholds for a plateau to be identified. We used probabilistic annual model-based estimates of family planning indicators and a simple smoothing approach to produce annual estimates of plateau probabilities under a variety of thresholds. Results: We applied our method to 48 countries in sub-Saharan Africa over the period 1980–2019 and found plateaus in MCP in ten countries (half in western Africa) and plateaus in DS in two (Niger and Nigeria). We found no indication of a temporal association between MCP plateaus and fertility transition stalls, although we observed that some fertility transition stalls occurred when MCP was low. Contribution: Our method provides an updated, robust way to identify plateaus in contraceptive prevalence. Moreover, it could feasibly be applied to probabilistic model-based estimates of other demographic indicators, such as total fertility.

中文翻译：

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撒哈拉以南非洲避孕普及率高原的新视角：概率方法（作者：Mark Wheldon、Vladimíra Kantorová、Joseph Molitoris、Aisha Dasgupta）

背景：撒哈拉以南非洲地区的生育率下降速度比其他地区要慢，极其缓慢的转变时期通常被称为停滞期。计划生育方案投资不足被认为是一个关键因素。然而，虽然有大量关于生育转变停滞的文献，但避孕普及趋势中的类似现象却很少受到关注。目的：我们提出了一种概率方法，用于检测现代避孕普及率（MCP）的平稳状态和现代方法满足的计划生育需求（DS）。方法：我们根据水平、比率和概率条件定义了避孕普及率平台，每个条件都具有要识别的平台的相关阈值。我们使用基于概率年度模型的计划生育指标估计和简单的平滑方法来生成各种阈值下平台概率的年度估计。结果：我们在 1980 年至 2019 年期间将我们的方法应用于撒哈拉以南非洲的 48 个国家，发现 10 个国家（一半在西非）的 MCP 处于平稳状态，2 个国家（尼日尔和尼日利亚）的 DS 处于平稳状态。尽管我们观察到当 MCP 较低时会出现一些生育率转变停滞，但我们没有发现 MCP 平台期与生育率转变停滞之间存在时间关联的迹象。贡献：我们的方法提供了一种更新的、可靠的方法来识别避孕普及率的平稳期。此外，它还可以应用于基于概率模型的其他人口指标（例如总生育率）的估计。