Covid-19: NYC 5 Boroughs, Nassau & Westchester to 10.19.20
These are plots of daily counts of confirmed cases as reported to/by Johns Hopkins. The peaks and troughs partly reflect reporting quirks – such as reporting times of labs, weekends or holidays when some are open, others closed, etc. The plot would be a lot smoother if we average them out. But we would also lose valuable information depending on what we are looking at. If you’re looking at stock prices over the last year – averaging out to make the graph smoother makes sense. Brokers selling volatile stocks understand this. A smooth upward sloping graph sells, a busy graph that rises and plunges day to day scares people. But if a person is sick and had a temp of 101ºF, that is the temp you are reporting to the doctor. Not a moving average of the last week or two weeks. Which stock to pick depends on its return over a period of time. A doctor’s course-of-treatment decision depends on the patient’s readings, and on the centrality of time to the decision. Your fever is here and now, the specific last few readings are very important. Contrariwise, your HbA1C, your average blood glucose over the last three months, is useful in diagnosing diabetes. Here and now, in my book, precludes the luxury of averages. Speaking of responding in real time, see my note about Hofstra below.
Nassau county is adjacent to New York City on the east and Westchester county is adjacent to NYC to the north. Unsurprisingly they move in tandem with the city. Around the end of August, Hofstra University re-opened for in-person classes. Almost immediately they experienced a spike in cases. You can see this in the line for Nassau county, where Hofstra is located. From under 4 cases per 100,000 population per day all through August, Nassau spiked towards 7 cases per day the last days of August and first week of September. Governor Cuomo of New York reacted in real time to this spike in daily reports, not an average, and threatened to shut down Hofstra for in-person classes unless they got a better handle on new infections in and around the campus. Three weeks later, Nassau is back in sync with the rest of the NYC area.