I’ve analyzed enough health care data to know that this can’t be a real increase in cases. It has to be a data reporting glitch. I just have to work out what it is.
Here’s the answer: This is a result of the Memorial Day. And it will disappear tomorrow. The reason is that today’s seven-day moving average actually has eight days’ worth of cases it in, for states that didn’t report data on Memorial Day.
A simple spreadsheet illustrates what’s happening. Here I’ve represented a day’s worth of new cases with a “1”. A lot of states didn’t report new cases on Memorial day, but instead reported two days’ worth of cases the next day. With that reporting pattern, you’ll see a dip in the seven-day moving average reported on Memorial day, and an offsetting jump in the seven-day moving average seven days later.
