Calculating Death Rates for the COVID-19 Virus during an On-Going Epidemic

For several reasons the death rate from an epidemic (deaths per infected persons) is difficult to determine before the epidemic ends. I proposed a procedure to calculate the death rate mid-epidemic by estimating the relationship between daily reported deaths and the daily time lag structure for reported cases associated with deaths. The structure is the spread of days over which cases are associated with deaths. The death rate is calculated by dividing the deaths by a weighted average of cases in that spread. I calculate the lag structure for COVID-19 cases worldwide, excluding China and Korea. This produces an estimated death rate of approximately 4.5 percent of reported cases.