This chart is tracking the growth factor of daily new COVID-19 cases in Michigan.
Growth factor is the factor by which a quantity multiplies itself over time. We are also tracking the growth factor of the 7-day moving average of cases.
The formula used is every day’s new cases divided by new cases on the previous day.
According to Worldometers, which specializes in these types of charts, a growth factor above 1 indicates an increase, while one which remains between 0 and 1 it is a sign of decline, with the quantity eventually becoming zero, while a growth factor constantly above 1 could signal exponential growth.
Exponential growth is defined as growth whose rate becomes ever more rapid in proportion to the growing total number or size.
The following chart shows Michigan’s daily COVID-19 cases, as reported by the state. There were 1,481 new cases reported April 4, then 1,493 new cases reported April 5, then 1,503 new cases reported April 6. Those are all relatively close daily new cases totals, and that’s why the growth factor for April 5 and April 6 is close to 1 on the chart above.
Then, on April 8, we saw the state’s lowest daily new cases report total since March 31. The 1,376 daily new cases on April 8 registered a less than 1 growth rate since April 7.
A .53 growth factor on April 12 was the lowest since March 16.