Analysis of Flagrant Fouls in the 2024 WNBA season

Caitlin Clark was flagrantly fouled 6 times this year. What’s the probability of that happening? I answer this question and more with a Poisson process.

Network plot of flagrant fouls in the 2024 WNBA Season. Chart by Vaughn H.

When I took a look at this WNBA regular season’s flagrant fouls, one thing stood out. Caitlin Clark has been on the receiving end of a lot of flagrants this year. The above network plot shows all of this year’s flagrants, with the arrow pointing to who was fouled. Just looking at the network plot, it’s clear that an unusual amount of these flagrants have been directed towards Clark, the majority of which are from the Chicago Sky. Before I get yelled at in the comments, let me make myself clear: I am not writing this to paint the Chicago Sky in a bad light. I am also not here to write a pity story for Clark. But, fans and reporters alike have focused on this issue, and I figured it’d make for an interesting analysis. In this write-up, I hope to create two things: a formula for expected flagrant fouls (based on minutes played) and a probability for each player’s number of flagrants.

Before diving into how I did the analysis, some quick stats:

• There were 35 flagrant fouls called this year in the WNBA

  • 34 if you exclude Diana Taurasi’s later-removed call. Values in parentheses represent percentages without this flagrant. Example: 34/35 and 34/34 reported as 97% (100%)

• Players fouling Caitlin Clark accounted for 17.1% (17.6%) of all flagrants this year

• 11.4% (11.8%) of all flagrant fouls were Chicago Sky players fouling Caitlin Clark

Calculating Expected Flagrants

When analyzing flagrant fouls across players, I wanted to calculate an expected flagrant foul metric. To do this, I used a Poisson process, which assumes fouls happen uniformly over time. This also assumes that events are random and occur independently of each other.

First, I calculated the MLE (Maximum Likelihood Estimate) for the rate at which fouls occur. This was done by dividing the total number of flagrant fouls by the total minutes played by all players across all games. Next, I needed to figure out how likely it was for each player to have committed the number of fouls they did, based on the time they spent playing.

I calculated the expected number of fouls for each player by multiplying their minutes by the MLE. This gave me an estimate of how many fouls each player "should" commit if fouls were distributed uniformly. Using the Poisson distribution, I then computed the probability of observing the actual number of fouls each player committed. This allowed me to see if certain players were committing more (or fewer) fouls than expected, helping me identify those who were outliers in terms of flagrant foul behavior. These probabilities can be found in the “probability” column of the following tables.

When assessing flagrant fouls given in the WNBA, one surprisingly nice idea comes to mind. There aren’t actually that many flagrants called. In the age of league reviews and slow-motion cameras, I’d like to think that players in the WNBA are relatively clean. I’d like to also highlight that a flagrant doesn’t mean a player is dirty. Rather, it simply means there was a foul given for a play that was interpreted to be unnecessary.

Flagrant fouls were less common this year, with 35 being called, compared to last year’s 65. Furthermore, nobody with multiple flagrants last year had multiple flagrants this year. This year’s leader in flagrants, Chennedy Carter who had four, didn’t even have a single flagrant in her career before 2024.

This chart is interesting, as it shows Clark was fouled flagrantly double the next person in the league this year. Assuming everyone has the same chance of being fouled, the probability of Clark being on the receiving end of six flagrants is 1 in 100,000 or 0.001%. This leads me to believe, pretty confidently, that players were being called for flagrant fouls on Clark at a higher rate than others in the WNBA. Does this mean she was targeted because of the off-court narrative? Not necessarily.

So why is Clark fouled so much?

Three main reasons come to mind. First, if players have ill intentions for a specific person. Second, if someone requires more intensity than defenders are used to. Third, if referees are especially cautious around a specific individual. In the case of Caitlin Clark, I think all three reasons are at play. I don’t think the “out to get her” narrative is the only one, and hopefully, I can convince you that.

Yes, some of the players are more physical with Clark, and at least one or two of the flagrants seem intentional. But, that doesn’t mean every foul requires a specific narrative to be pushed. Clark is unique on offense, and her talents likely require a higher intensity than defenders are used to giving. As more intensity is given, sloppy plays are more likely to occur. Clark also will often “blow by” defenders, with the defender contesting a driving layup from behind. This could lead to more people hitting her in the head, even if on accident.

I don’t think the referees like Clark more than anyone else (she did lead the league in technical fouls this year) but unprecedented attention has been placed on her. If a ref has the idea in their head that Clark is at higher risk for a flagrant, they’re more likely to call one regardless if the foul is a flagrant or not. Bias is tricky to quantify, but I think it may be a factor at play.

To summarize this section, Caitlin Clark represents a perfect storm of factors that may cause more flagrants to be called when she is fouled. Are a couple of the flagrants on her due to ill intention? Probably. Are they all? I don’t think so.

Conclusions

Hopefully, this analysis has added some rationality to a common talking point we’ve seen across the league. Yes, Caitlin Clark is being treated differently. Is it by the refs or the players? That’s the question people can’t seem to agree upon. From my perspective, it seems both seem to be at play, and each foul would need to be assessed individually to make any strong conclusions.

I’m also very cautious that these statistics would be extrapolated. This does not mean that the Chicago Sky is a dirty team, or targeting a specific individual. Investigating on a case-by-case basis, with player interviews, would be the only way to figure this out. Assuming the players would be honest, of course. There are a lot of factors at play here and they all are worth considering.

As always, thanks for giving this a read. If you have further ideas for improvement or other WNBA stats you’d be interested in seeing, please leave a comment!