Here’s the coronavirus growth rate through March 31. Italy continues to slowly flatten and still has a chance of peaking within a week. Everybody else is tracking about the same as usual too.

I’ve gotten a lot of comments lately about the particular way I construct my charts. The most frequent questions have to do with my choice of Day 0 and whether or not I should simply show absolute death tolls rather than growth rates.

Day 0 is an interesting question. I am a per-capita guy: I think you need to account for a country’s population to get an accurate picture of how they’re doing. That’s why I chose to count Day 0 as the first day that deaths surpassed one in ten million. I figure that 33 deaths in the United States is about equivalent to 6 deaths in Italy.

But there’s an argument for simply assigning Day 0 to the day with the very first death. After all, in the early stages of an epidemic the numbers are so small that the size of the country doesn’t really matter: it’s going to grow at an exponential rate for at least several weeks until it starts to hit resistance as a significant percentage of the population becomes infected. So let’s take a look at mortality rates counting from the day of the first COVID-19 death in each country:

Note that I’m still using deaths per million. Especially now that we have more than a month of the pandemic under our belts, I can’t persuade myself that this is wrong. Using absolute deaths seems like nothing but a way to make big countries look gratuitously bad. It’s like calling California the drunk driving capital of the country without mentioning that this is only because it has more people than any other state.

As it turns out, this chart doesn’t look all that different from my usual batch. Using a different definition of Day 0 just doesn’t change much. For now, then, I’m going to keep them the way they are so that they’re comparable from day to day. I may change them later if I need to.

How to read the charts: Let’s use France as an example. For them, Day 0 was March 5, when they surpassed one death per 10 million by recording their sixth death. They are currently at Day 26; total deaths are at 588x their initial level; and they have recorded a total of 52.7 deaths per million so far. As the chart shows, this is slightly below where Italy was on their Day 26.

The raw data from Johns Hopkins is here.