“If you look at the rates of new cases that are being diagnosed, we’re on an exponential curve,” NIH Director Francis Collins told Peter Wehner for an article in The Atlantic. What does this mean, “we’re on an exponential curve”, and why does it matter? First, what it means is that the best function to describe the rate at which the number of cases is changing day-by-day is an exponential function with the form: y = a∙b^x Where: y is the number of cases a and b are both just some constant, like 7 or 0.2983, and these are found by some fancy mathematical process so that the resulting plotted curve is as close to the actual data points as possible. x is the number of days from when you started