Estimating excess mortality is challenging. The metric depends on the expected mortality level, which can differ based on given choices, such as the method and the time series length used to estimate the baseline. However, these choices are often arbitrary, and are not subject to any sensitivity analysis. We bring to light the importance of carefully choosing the inputs and methods used to estimate excess mortality. Drawing on data from 26 countries, we investigate how sensitive excess mortality is to the choice of the mortality index, the number of years included in the reference period, the method, and the time unit of the death series. We employ two mortality indices, three reference periods, two data time units, and four methods for estimating the baseline. We show that excess mortality estimates can vary substantially when these factors are changed, and that the largest variations stem from the choice of the mortality index and the method. We also find that the magnitude of the variation in excess mortality is country-specific, resulting in cross-country rankings changes. Finally, based on our findings, we provide guidelines for estimating excess mortality.

中文翻译：

---

对 COVID-19 大流行导致的超额死亡率的敏感性分析

估计超额死亡率具有挑战性。该指标取决于预期死亡率水平，该水平可能因给定选择而异，例如用于估计基线的方法和时间序列长度。然而，这些选择通常是任意的，不受任何敏感性分析的影响。我们揭示了仔细选择用于估计超额死亡率的输入和方法的重要性。利用来自 26 个国家的数据，我们调查了超额死亡率对死亡率指数的选择、参考期包含的年数、方法和死亡序列的时间单位的敏感程度。我们采用两个死亡率指数、三个参考期、两个数据时间单位和四种方法来估计基线。我们表明，当这些因素发生变化时，超额死亡率估计值可能会发生很大变化，并且最大的变化源于死亡率指数和方法的选择。我们还发现，超额死亡率的变化幅度因国家而异，导致跨国排名发生变化。最后，根据我们的发现，我们提供了估计超额死亡率的指南。