March 20 – Forecasting COVID-19 in Mississippi

Yesterday I published a forecast for 70 total cases in Mississippi today. That forecast was based on the hope that we could manage to stay below a 50% daily increase in the number of reported cases. Unfortunately, Mississippi continues to see cases increasing by 50-60% each day. I had a bad feeling we would be closer to 80 cases today, and it turns out that my gut was right. Continuing this trend means that we may wake up on Monday morning and find out Friday’s 80 cases have turned into over 250-275 cases. By the end of next week, that number rises to around 1,500 cases.

March 20 – Daily growth of COVID-19 in Mississippi

Slowing the growth rate now is really important. I showed you yesterday how that makes a huge difference in the overall outcome for the people of Mississippi. This graph shows you what can happen if the daily growth rate stays around 50%. It shows the entire population of Mississippi being infected within 30 days. 

Daily forecast of COVID-19 in Mississippi with constant growth rates (next 30 days)

Before you start to panic, let me tell you that I don’t think the whole state will be infected in the next 30 days. There are a variety of reasons why this looks possible in a model but not in reality.

In order for everyone to be infected, every person must come into contact with another contagious person. Our distance and social networks naturally keep us isolated into relatively small groups. Social distancing effectively reduces those interactions even more. I am staying at home except for brief trips into my office. When I do visit my office, my interactions are limited to a very small set of people. Therefore, I cut down potential interactions that would be necessary for the whole state of Mississippi to end of sick in the next 30 days. If I am lucky, I won’t encounter a contagious person at all. Social distancing can both slow the growth rate and cap the number of people who will be infected by the virus.

If you don’t believe any of this is a big deal and are not staying at home, how many cases need to be reported for you to do so? How many people have to be sick, in the hospital, or dead for you to believe? 500? 1,000? What if I told you that by the time we get to 500, you are a week away from having over 5,000 cases? This is why there is a call to “flatten the curve.” As silly as it may seem right now with 80 confirmed cases in Mississippi, it’s time to do your part to slow the spread now.

Don’t fear the green line but be aware of the green line. This is what could happen if we did nothing. If we can manage to cut the growth rate in half as quickly as possible, it has enormous consequences over the long term. Cutting the growth rate in half today would mean the difference between having 524 cases in 10 days or having 4,441 cases in 10 days. 

Cutting the growth rate in half makes a BIG difference!


I am not a medical doctor, a healthcare specialist, biologist, or public health professional. I am a trained financial economist building an economist growth model and explaining the impact of personal and policy outcomes on that model.

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