COVID-19 deaths are underreported in different countries for different reasons, including limited capacity to test for infection, inadequate death registration systems, and inaccurate reporting due to political factors. As a result, health officials based their analysis on the concept of "excess mortality"- a measure of the difference between deaths from all causes observed or estimated during the pandemic and the number of deaths that would be expected from the past mortality trends. For example, the Economist, estimates 17.55 million (95%% uncertainty interval 16.62-18.48 million) excess deaths between 1 January 2020 and 31 December 2021.