Simpson’s Paradox can make sports stats look weird
Simpson’s Paradox can make sports stats look weird
Let’s look at two NBA legends, Larry Bird and Reggie Miller.
When it came to two-point shots, Larry shot 50.9% and Reggie shot 51.6%, so Reggie was better there.
When it came to three-point shots, Larry shot 37.6% and Reggie shot 39.5%, so Reggie was better there as well.
However, when you add them together Larry was the better overall shooter (49.6% to 47.1%)! How is that possible?
Simply put, Larry shot many more two-point shots than three-pointers, at least compared to Reggie, so his total average was closer to the (higher) two-point number.
It’s weird, I know.
This old video from “singingbanana” helps explain it using a medical example:
As James says in the video, it’s a case that shows how important it can be to pay attention. Initial logic says that Reggie was a better overall shooter or that “Drug B” was more effective, but the math just doesn’t play out that way.
This can apply to medical data or website stats or a variety of other things you might come across. People will often try to show numbers in a way that supports a particular agenda, so knowing about little oddities like this can help you to always be able to sniff out the truth.