Differences in COVID-19 mortality: Implications of imperfect and diverse data collection systems

The worldwide COVID-19 emergency has led to substantial variations in the data collection process across countries scrambling to produce real-time information, resulting in imperfect mortality statistics. To address this problem, we analyze COVID-19 death counts from the Demography of COVID-19 Deaths database (https://dc-covid.site.ined.fr/en/) and discuss their limitations. We describe and illustrate important data-related issues that may hinder international comparisons. To alleviate these difficulties, we classify sources according to their data’s completeness then analyze and compare death counts for 16 countries. Finally, we discuss the importance of understanding data collection characteristics and provide recommendations for dealing with imperfect statistics.