The COVID 19 pandemic has expanded our vocabulary with terms like “social distancing” and “self-isolation.” In an article in Slate, Jeremy Samuel Faust who is a physician and instructor at Harvard medical school gave us one more; “case fatality rate” or CFR. Initial reports have the CFR for this disease at 2 to 3 percent but Faust writes that the actual numbers could be much lower. Using the cruise ship the Diamond Princess - a unique petri dish -  as his case study he explains that of the 3711 people on board, at least 705 tested positive for the virus and 6 people have died. A CFR of 0.85 percent.