Support for Forecast

I commented on May 17th that the relaxation of social restrictions would show up in the data between May 15th through the end of June and included a table of projected dates for each state.

I’ve also explained the 3+ week lag from social changes/impacts to visibility in the data.

The graph below is essentially a derivative. The blue line represents the slope of the data from the three weeks prior to the date indicated. The slope of a line indicates how steeply it is climbing or falling. If it’s climbing, the slope will be above zero, if it is falling, it will be below zero. The distance from zero indicates how quickly it’s either rising or falling.

Right click on images to open in a new window to enlarge and scale properly.

Remember, I had said that releasing restriction would only BEGIN to show up in the data about May 15th. Given the roughly weekly cycles in the data, I had no way of having any indication the data to make that forecast on May 17th. It was strictly based on my understanding of the clinical course and epidemiology of the disease.

I added a black dotted trend line that is a moving average over a 7-day period to eliminate this cycling. Look at the lowest point of this trend line. It’s right about May 16th or 17th.

The important point though is that we have seen the impact of only some states easing restrictions. There also has been incremental easing of them, where things like allowing 25% capacity in restaurants, gathering of people at worship services with restrictions on crowd size, etc. have come into play. This is also with at least some social distancing taking place in many areas (see map below).

Also, look at the red line on the graph. That is zero. When the slope graph goes above it, cases are increasing. Given that we aren’t even toward the end of the period of seeing impacts from states opening up which will be at the end of the month, it’s pretty safe to assume from this trend that we are going to see cases rising again, and I have been telling people to expect that it will become obvious to most people about June 15th. What remains to be seen after that date is how quickly they will rise. I’m putting my money on exponential growth that will overwhelm the ICU capacity in many areas by the end of the June.


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