About/Best Of

Mathletix is a website about statistics, sports, machine learning, AI and behavioral economics, written by me, Casey Durfee. You can contact me at csdurfee@gmail.com.

All code is available at https://github.com/csdurfee or https://www.kaggle.com/code/caseydurfee

The highlights, so far:

The hot hand in the NBA

Read the full series: https://mathletix.net/tag/the-hot-hand.html

The "hot hand" doesn't exist for field goal attempts in NBA basketball. In fact, NBA players are significantly less streaky than they should be. This unstreakiness is mostly due to shot selection. For NBA players, their shooting percentage by type of shot doesn't change much based on how well they've been shooting lately -- there is definitely no hot hand in that sense. A player who has made 4 or 5 out of the last 5 shots isn't significantly more likely than average to make the next one, controlling for shot difficulty.

While FG% by type of shot doesn't change, shot selection does -- on average, NBA players take higher percentage shots when they've been shooting poorly recently (they go get a bucket), and lower percentage shots when they're shooting well (they take a heat check). These heat check shots tend to be more inefficient shots as well (lower expected value), so this behavior definitely costs teams points, and possibly wins.

The real world is far streakier than our brains are equipped to deal with. Players believe they are streaky, which causes them to do things that make them less streaky than they would be by chance. Even though they're not as streaky as they should be, NBA players still seem streaky to people who watch basketball, myself included. We tend to treat 3 or more makes or misses in a row as a significant event, even though it's fairly likely.

Sports betting

https://mathletix.net/tag/your-parlay-sucks.html

A long investigation into sports gambling and how it works, mathematically and psychologically. So far, I've published pieces about betting spreads, line movements, which teams get bet on the most, and how random walks work.

Some educational value

https://mathletix.net/tag/some-educational-value.html

Pieces about statistics and machine learning including how normal approximations work, pitfalls of ensemble learning, and harmonics in music.