Nylon Calculus: Fouls drawn don’t mean as much as you think

There was an interesting tweet posted by Trevor Lane of Lakers Nation that got my attention, and I thought it was worth reviewing how fouls are related to shots close to the basket, and whether they show any relation to having a high offensive rating, SRS, and overall team winning percentage.

It’s interesting because fouls have a big impact most certainly on how fans watch a basketball game. If the team you’re rooting for can’t catch a break underneath the hoop from the ref, it can take the air out of the building and ruin momentum. Even fans can get pretty upset. But does this discrepancy in fouls called versus the number of close field goal attempts hold weight? Are the Los Angeles Lakers not getting any help from the referees down low?

I looked at data from 2017 to yesterday to help work through the tweet, and see what we might be able to unravel from the data. All presented data are per game and up to date as of last night.

Is any team getting help at the rim?

There’s the assumption that teams attempting the most shots down low are deserving of more fouls called because the presumption exists that there’s more physicality in that part of the court. If a basketball team attempts more shots within five feet, they’re bound to rack up more overall fouls. The following graph shows how that thinking might be incorrect.

As indicated by the low-value R2, attempting more within five feet doesn’t necessarily mean the team will get more overall foul calls. In fact, you’ll notice that the Los Angeles Lakers specifically are getting more calls this year in comparison to last year already. That of itself might be due to the increased pace we’ve witnessed this season, or due to some superstar effect.

Anyways, how much value are we really seeing from teams attempting a bunch of shots down low? We have to ask what difference is there in overall fouls drawn per game for teams that have high or low offensive ratings.

At this point, I suppose it’d be nice for teams looking to increase offensive productivity to be demanding more foul calls but it may not even matter. To be clear, the above graph is looking at all fouls drawn, not just at the rim. But let’s say a team like the Los Angeles Lakers does get rewarded two or three extra calls per game, it’s not going to help the Lakers on the offensive end, let alone by overall team performance.  

Some of the most elite teams (SRS > 8) don’t draw as many foul calls as one might expect. This year’s Milwaukee Bucks have run a great offense this year without using fouls as leverage to win games. One could argue that too many fouls would, in essence, be stalling teams from achieving offensive efficiency.

The value down low

Since it’s most probable that getting fouls shots down low may not be all that valuable, why strive for so many buckets in the paint? For the Los Angeles Lakers, they’re probably happy with how things are turning out for them because of the shots they’re making down low.

Specifically, the additions of JaVale McGee and LeBron James alongside Kyle Kuzma have been a boon to the Lakers’ offense down low this season. Those three players are in the top 20 in terms of field goals attempted within five feet, making a combined 17.2 field goals at a 71.5 percent clip in that zone. That’s about 34 guaranteed points per game, and honestly more fouls might just disrupt that flow. Combined, the three Lakers combined for a free throw percentage of about 74 percent. If these Lakers players were awarded three more fouls per game down low, that risks potential automatic buckets they’re already getting.

And as far as trying to switch some of these attempts down low over to 3, that might not even be worth it, especially for this season. The Lakers might be onto something in terms of exploiting 2-point shots underneath the basket. The team has been making the same amount of 3-point shots this year — compared to last year — achieving a just-outside-of-top-ten type of offense.

The real problem, instead, might just be their torrid defensive efficiency.