Aggregate measures of family planning are used to monitor demand for and usage of contraceptive methods in populations globally, for example as part of the FP2030 initiative. Family planning measures for low- and middle-income countries are typically based on data collected through cross-sectional household surveys. Recently proposed measures account for sexual activity through assessment of the distribution of time-between-sex (TBS) in the population of interest. In this paper, we propose a statistical approach to estimate the distribution of TBS using data typically available in low- and middle-income countries, while addressing two major challenges. The first challenge is that timing of sex information is typically limited to women's time-since-last-sex (TSLS) data collected in the cross-sectional survey. In our proposed approach, we adopt the current duration method to estimate the distribution of TBS using the available TSLS data, from which the frequency of sex at the population level can be derived. Furthermore, the observed TSLS data are subject to reporting issues because they can be reported in different units and may be rounded off. To apply the current duration approach and account for these data reporting issues, we develop a flexible Bayesian model, and provide a detailed technical description of the proposed modeling approach.

翻译：家庭计划的综合指标用于监测全球人群对避孕方法的需求和使用情况，例如作为FP2030倡议的一部分。低收入和中等收入国家的家庭计划指标通常基于横断面家庭调查收集的数据。近期提出的指标通过评估目标人群中性行为间隔时间（TBS）的分布来考虑性活动。本文提出了一种统计方法，利用低收入和中等收入国家通常可获取的数据来估计TBS分布，同时解决两大挑战。第一个挑战是性行为时间信息通常仅限于横断面调查中收集的女性末次性行为时间（TSLS）数据。在我们的方法中，采用当前持续时间法，利用可用的TSLS数据估计TBS分布，从而推导出人群层面的性行为频率。此外，观察到的TSLS数据存在报告问题，因为它们可能以不同单位报告或被四舍五入。为应用当前持续时间法并处理这些数据报告问题，我们开发了一个灵活的贝叶斯模型，并提供了所提出建模方法的详细技术描述。