Team Penalty Splits Expanded

Over at the Team Ratings and Statistics page is, among other things, an overview of how teams score and defend when in and out the penalty. It’s a situation in the NBA beginning after a team draws or commits four fouls in one quarter or, if not that, just one foul during the last two minutes[1. In overtime, this goes from four fouls to give to three.], and from that point on both shot fouls and personal fouls lead to two free throws. This always seemed like a big deal, rightfully an every-game topic for broadcasters and Twitter, but we haven’t had more than just an idea of how important the penalty was until this season.

Though what I’ve published so far relating to the penalty has only been a simple overview, we now know at least some essentials. Below is a look at two of them which are how much time teams actually spend in the penalty and the net rating when this situation happens compared to when teams have fouls to give:

On average, teams spend about one-fourth of their total possessions in the penalty situation and while every advantage counts, this one has been inflated by late-game fouling.[1. Some situations, rare or not, to factor into the first three quarters would be using the foul to give, heaves, and having more bench players on the floor during the latter-half of the first and third quarters, but fourth quarters have their own plays like desperation shots and team turnovers out of sportsmanship when the game is out of reach.] Maybe the penalty just does not offer the same advantage in this era of basketball compared to the past thanks to a decline in offensive rebounding, more three-point shooting, and committing fewer fouls. A post from 82games.com a decade ago, for example, showed that the increase in offensive efficiency was about three times as large back then compared to now, and teams spent about five percent more of the game in the penalty, though the latter appeared to be measured in minutes instead of possessions.[1. Probably obvious but penalty time, measured in minutes and seconds, would be a slightly larger percentage because of possible shot fouls on the fourth team foul or second foul with two minutes remaining. There’s also the occasional end-of-quarter foul to give that leads to no shot, free throws, or turnover, so a possession is not credited.]

Of course, league averages are helpful, but solid scoring teams have opposing defenses in the penalty more often and good defenses stay out of this situation, which can lead to strange results by itself. Five of the top six teams in possessions with opposing defenses in the penalty have scored less efficiently with that advantage compared to without it, and when taking out fourth quarters the top seven teams have all been one to nine points worse per 100 possessions. Meanwhile on defense, the Lakers are not exactly fantastic on that end, but they came into Sunday defending 7.2 points better per 100 possessions with no fouls to give versus having some in their back pocket. When taking out fourth quarters, the Lakers’ difference increases to 12 points.

So that’s all hopefully helpful to know, but until now there hasn’t been anything to help answer why teams are better or worse in this situation of the game. The splits I’ve added now still won’t answer everything, but maybe they’ll explain things a bit better for why the Lakers have defended much better when they’re in the penalty, for example. Some statistics included were true shooting, and effective field goal percentages, but also others such as free throw rate, three-point accuracy and percentage of field goals being assisted.

To start, below is a quick look at league-averages in and out of the penalty. Some important stats weren’t included because of timeliness:[1. I wanted to include, of course, fouls, but also rebounding. At the moment I haven’t had a chance to throw either in. Using just nba.com’s play by play data, rebounds aren’t specified whether they’re offensive or defensive, and filtering types of fouls takes too long. At least at the moment.]

So free throw rates have more than doubled when in the penalty, teams shoot worse on three-pointers and assist on fewer made field goals in general, but at least they turn it over less frequently. Some of this was covered in an introduction post, but it’s still worth noting that the results are similar after a couple more months. Fourth quarters were a problem, though, throwing some statistics off. A couple weeks ago I split this all by quarters[1. I wanted to update those quarter-by-quarter splits, but it simply takes too long with the current way get them. Working on finding a quicker way with R and stuff.], and free throw rates in fourth quarters while in the penalty were at 61.5 percent and the Rockets and Clippers had free throw rates over 100. There were slightly fewer turnovers per 100 possessions and true shooting percentage during that quarter jumped to 56.5 percent.

As for a look at each team, below is a table look at scoring with options to sort and also a couple filters:

I’m not going to cover every team, but some things stick out. The Clippers lead the league in portion of their possessions with the penalty to their benefit, but are 4.5 points per 100 possessions worse than when the defense has fouls to give. Their free throw rate, thanks to DeAndre Jordan, increases by over 50 percent, but of course they make a smaller percentage of their free throws in that situation and they’ve shot nine percent worse from the three-point line. That doesn’t answer everything about the Clippers, but hopefully it’s worth noting.

The Timberwolves have been pretty unusual, too, fifth in offensive rating with the penalty on their side at 113.4, but they’ve struggled badly when not in the penalty with an offensive rating of just 100.9. Clicking on the ‘Diff’ filter shows that they have some of the largest differences in the first three statistics.

Some other notes:

• When having the defense in the penalty versus being out of it, every team improves their free throw rate by at least 17 percent.
• Only the Sixers and Knicks assist on more field goals when in the penalty.
• Oklahoma City, Milwaukee, and Boston are the only teams to turn it over more per 100 possessions in the penalty.
• Golden State’s the only team to improve their three-point percentage by over one percent, and their rate has improved by 3.6.

As mentioned earlier, the Lakers were a team to note on the defensive end. We can get something of an idea why when looking at splits for that side of the floor, too:

The difference for the Lakers in three-point defense has been 12 percent, highest in the league. The Wizards are right behind them with a difference of 11.5, but the difference in their defensive rating is nowhere near as large since they’ve been a not-terrible defense with fouls to give. There are plenty of other things to note, significant or not, like Dallas being the only team to allow more assisted made field goals with no fouls to give.

Hopefully, those splits offer a better idea of why certain teams have performed the way they have when the penalty comes into play, but there’s still plenty of work to be done. Teams might shoot a higher or lower percentage at the rim, or maybe the difference in offensive rating is not as large as expected partly because of shots coming from mid-range. Defender distance also seems pretty important since touch fouls lead to free throws, which makes it seem like some players, like Chris Paul, thrive when defenses have no fouls to give.[1. For example, Paul drew 47 shot fouls last season with 13 and-1s, according to Basketball-Reference, but had 321 free throw attempts. Pretty weird even with late-game fouling to consider.] Splits not just for teams but for players could also be done.

There’s a lot more to look at, but this seemed like a halfway decent next step.

Statistics were from NBA.com play-by-play data unless noted otherwise.