  Factors such as non-uniform definitions of mortality, uncertainty in disease
prevalence, and biased sampling complicate the quantification of fatality
during an epidemic. Regardless of the employed fatality measure, the infected
population and the number of infection-caused deaths need to be consistently
estimated for comparing mortality across regions. We combine historical and
current mortality data, a statistical testing model, and an SIR epidemic model,
to improve estimation of mortality. We find that the average excess death
across the entire US is 13$\%$ higher than the number of reported COVID-19
deaths. In some areas, such as New York City, the number of weekly deaths is
about eight times higher than in previous years. Other countries such as Peru,
Ecuador, Mexico, and Spain exhibit excess deaths significantly higher than
their reported COVID-19 deaths. Conversely, we find negligible or negative
excess deaths for part and all of 2020 for Denmark, Germany, and Norway.
