Why Florida Doesn’t Look as Deadly as New York

(Bloomberg Opinion) -- A few weeks ago, I made a prediction that I in no way wanted to be correct: By early August, the Covid-19 death toll in Florida would average 600 a day, rivaling the worst days of the pandemic in New York.

I was wrong. As of August 4, Florida's seven-day average was just 184, according to the latest official data. Unfortunately, I don't see this as reason for relief.

Here's where I might have erred: I made some ambitious assumptions about how New York's experience could be applied to Florida. Specifically, I assumed a straightforward relationship between the percentage of Covid-19 tests coming out positive and the actual number of cases: The higher the percentage, the more cases are going unrecorded because people with mild or no symptoms aren't getting tested. The relevant positive rate for New York was more than double Florida's (44% versus 18%), so I estimated that New York's mid-April peak of 11,434 cases would be about 24,000 in Florida terms. It followed that if New York ended up with 1000 deaths a day, Florida — with about 15,000 cases — should see more than 600. Perhaps the relationship isn't that simple. Maybe New York actually had a lot more cases, or maybe Florida's death rate really is different.

That said, I also should have considered whether Florida's methodology for recording deaths was even comparable to New York's. States are supposed to follow Centers for Disease Control and Prevention guidelines, but in reality they all do things differently, and some use pretty narrow definitions. According to the watchdog organization Florida COVID Action, for example, last month Florida started attributing deaths to Covid-19 only if the disease is confirmed as the “primary cause.” This means that a lot of Covid deaths are probably being recorded as pneumonia or as acute respiratory distress syndrome.

So how much might Florida or New York be undercounting Covid-19 deaths? One way to get a sense: Look at how deaths overall compare to the same period last year. Granted, this is probably an underestimate of coronavirus fatalities, because deaths by other causes declined after the pandemic started compelling people to stay safe and away from each other. But it's better than nothing.

Data compiled by The New York Times suggest that New York State had about 9,600 excess deaths during its worst week in April, compared with about 6,600 official Covid-19 deaths — suggesting an undercount of about 30%. Florida had about 1200 excess deaths in the week ending July 11, compared with an official report of about 500, suggesting an undercount of almost 60%. Moreover, there's a lag in death reporting — and that lag appears to have gotten worse — so excess deaths are likely to end up higher still.

In other words, while my prediction about Florida's official Covid-19 death count was definitely wrong, the pandemic is probably taking a lot more lives in the state (and in other states) than meets the eye. Just applying the undercount estimate derived from excess deaths, Florida's 7-day average of 184 becomes about 440. The reality could be even worse. I certainly hope it's not, and that Floridians and all Americans will do what's needed to get the numbers down as quickly as possible.

This column does not necessarily reflect the opinion of the editorial board or Bloomberg LP and its owners.

Cathy O'Neil is a Bloomberg Opinion columnist. She is a mathematician who has worked as a professor, hedge-fund analyst and data scientist. She founded ORCAA, an algorithmic auditing company, and is the author of “Weapons of Math Destruction.”

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