Mathematical Malpractice Watch: Hurricanes

There’s a new paper out that claims that hurricanes with female names tend to be deadlier than ones with male names based on hurricane data going back to 1950. They attribute this to gender bias, the idea that people don’t take hurricanes with female-names seriously.

No, this is not the onion.

I immediately suspected a bias. For one thing, even with their database, we’re talking about 92 events, many of which killed zero people. More important, all hurricanes had female names until 1979. What else was true before 1979? We had a lot less advanced warning of hurricanes. In fact, if you look up the deadliest hurricanes in history, they are all either from times before we named them or when hurricanes all had female names. In other words, they may just be measuring the decline in hurricane deadliness.

Now it’s possible that the authors use some sophisticated model that also account for hurricane strength. If so, that might mitigate my analysis. But I’m dubious. I downloaded their spreadsheet, which is available for the journal website. Here is what I found:

Hurricanes before 1979 averaged 27 people killed.

Hurricanes since 1979 average 16 people killed.

Hurricanes since 1979 with male names average … 16 people killed.

Hurricanes since 1979 with female names averaged … 16 people killed.

Maybe I’m missing something. How did this get past a referee?

Update: Ed Yong raises similar points here. The authors say that cutting the sample at 1979 made the numbers too small and so therefore use an index of how feminine or masculine the names were. I find that dubious when a plain and simple average will give you an answer. Moreover, they try this qualifier in the comments:

What’s more, looking only at severe hurricanes that hit in 1979 and afterwards (those above $1.65B median damage), 16 male-named hurricane each caused 23 deaths on average whereas 14 female-named hurricanes each caused 29 deaths on average. This is looking at male/female as a simple binary category in the years since the names started alternating. So even in that shorter time window since 1979, severe female-named storms killed more people than did severe male-named storms.

You be the judge. I average 54 post-1978 storms totally 1200 deaths and get even numbers. They narrow it to 30 totally 800 deaths and claim a bias based on 84 excess deaths. That really crosses as stretching to make a point.

Update: My friend Peter Yoachim did a K-S test of the data and found a 97% chance that the male- and female-named hurricanes were drawn from the same distribution. This is a standard test of the null hypothesis and wasn’t done at all. Ridiculous.