Texas Longhorns Basketball: Looking Back at the Defense

We now have a little bit of distance from the 2011-2012 basketball season. It is a good point to look back and reflect. Previously, I have taken a look at the Texas offense, leaning heavily on results pulled from my play-by-play database. In this post, I want to review the Texas defense.

Texas had the #44 rated defense in division one this season, based on the kenpom.com ratings, which adjust for tempo and quality of opponents. This was Texas' weakest defensive team since the 2006-2007 team that featured Kevin Durant, DJ Augustin, and a whole bunch of underclassmen. Durant's individual offensive greatness wasn't enough to overcome a team that had a pretty serious flaw -- they had trouble getting stops. In particular, the 2006-2007 team was undermined by their trouble rebounding the ball, and they didn't do enough else well defensively to make up for this. The 2011-2012 Longhorns had a similar problem.

When we review the Texas defense, we see that they really struggled with two things. Texas was the 247th best defensive rebounding team in college basketball, as measured by defensive rebounding percentage. Texas also fouled a lot, allowing their opponents to shoot 0.42 free throws for every field goal attempt (ranked #271 in division one).

On the positive side, Texas forced an NCAA median level of turnovers (opponents turned the ball over in 20% of their possessions), which is a bit better than what Rick Barnes' teams usually do. The best thing that Texas did defensively was to hold opponents to an effective field goal percentage of 47%. Texas had the 79th lowest opponent effective field goal percentage in division one basketball. While this was a good number, it wasn't as good as we are used to seeing from the Longhorns. It also wasn't good enough to compensate for the other defensive problems, and allow Texas to compete with the top teams in the country.

Let's dig carefully through the data, to see if we can learn a little more about the Texas defense.

Diving into Texas' field goal percentage defense

There are two ways that a defense can lower their opponent's effective field goal shooting percentage (eFG%).

1. Prevent the offense from taking high efficiency shots, forcing them to shoot from less efficient spots on the floor. For example, the University of Wisconsin allowed their opponents to only take 24% of their field goal attempts from three point range (33% is about the average for division one basketball). Wisconsin's opponents ended up taking 42% of their field goal attempts on two point jump shots. These sorts of shots are generally the least efficient shots a team can take, as 2 point jump shots typically go in around 35% of the time.

2. Lower their opponents' shooting percentages from various spots on the floor. For example, Kentucky blocked roughly 19% of their opponents' attempts at the rim this season. Averaged over all of the shots taken in my play-by-play database, approximately 10% of field goal attempts taken at the rim are typically blocked. All of these blocked shots lowered Kentucky's opponents to a 53% shooting percentage on shots at the rim (the database average is 61%).

The NCAA median effective field goal percentage allowed was 49%. 49% is also what you get if you average over all of the shots attempted in my play-by-play database. Texas allowed an effective field goal percentage of 47%. So what did Texas do better then average? Below, I have listed a few things pulled from my database.

Shot distribution against the Texas defense -- database averages in parentheses

Percent of field goal attempts at rim = 31% (34%)
Percent field goal attempts 2 pt jumpers = 38% (33%)
Percent field goal attempts 3 pt shots = 31% (33%)

A typical NCAA game has about one third of shots attempted at the rim, one third of shots as two point jump shots, and one third of shots attempted from three point range. Texas' opponents took fewer attempts at the rim and fewer attempts from three point range than we typically see. This accounts for a bit more than one percentage point of the difference between the Horns' 47% eFG%, and the average value of 49%.

On defense, everything that you do to turn shots at the rim and three point shots into mid-range two point jump shots brings a benefit. Due to differences in shooting percentages, shots that are taken at the rim are on average worth about 0.5 points more than two point jump shots. Shots attempted from three are worth about 0.3 points more than two point jump shots. Some of the very best defenses in the country, teams like Kansas, Wisconsin, and Virginia, were good in part because they forced their opponents to take 38% or more of their attempts as two point jump shots.

Shooting percentages against the Texas defense -- database averages in parentheses

FG% at rim = 60% (61%)
FG% 2 pt jumpers = 32% (35%)
FG% 3 pt jumpers = 35% (34%)

Texas also received a small benefit from having opponents shoot 60% on shots at the rim, and 32% on two point jump shots. Texas' allowed shooting percentages for each type of shot accounts for a little less than one percentage point of the difference between the Horns' 47% eFG%, and the average value of 49%.

So we can conclude that a little more than half of the difference between Texas' defensive eFG% of 47% and the average value of 49% was due to the types of shots that Texas allowed, and a little less than half of it was due to a small change in shooting percentages for individual shot types.

Shot blocking data for the Texas defense -- database averages in parentheses

Blk% at rim = 10% (10%)
Blk% 2 pt jumpers = 8% (7%)
Blk% 3 pt jumpers = 1% (1%)
FG% at rim on unblocked shots = 67% (68%)
FG% at 2 pt jumpers unblocked shots = 35% (37%)

One of the main ways that teams have to reduce shooting percentages is by blocking shots. Texas was pretty much an average shot blocking team this season, blocking 10% of opponent's attempts at the rim, 8% of two point jump shots, and 1% of three point shots. Clint Chapman blocked an estimated 7.6% of opponents' two point shots while he was on the court. Alexis Wangmene, Jonathan Holmes, and Jaylen Bond each blocked between 3-4% of opponents' two point shots.

Texas' field goal percentages allowed on unblocked shots were pretty typical of the results in the database, and are similar to the percentages allowed by some of the better defenses in college basketball.

Shooting percentages broken down by time after taking possession

In my review of the Texas offense, I made use of shooting percentages on the first shot of a possession, broken down by how long they occurred after the start of the possession. We can use the same approach to look at the Texas defense. In the table below, I have listed the percent of initial field goal attempts Texas' opponents took broken down by time after taking possession. I have also listed the eFG% on these shots. Also shown are the average values for my database.

	% of FGAs		eFG%
Time	Texas	Average	Texas	Average
< 10 s	34%	31%	56%	54%
11-25 s	54%	54%	44%	47%
26-35 s	12%	15%	41%	43%

I have previously written about how transition opportunities work in basketball. Virtually every team scores more effectively in transition, and defenses struggle in transition. Even really good defensive teams, like the Kentucky Wildcats, gave up an effective field goal percentage near the database average in the first 10 seconds of a possession. Texas' opponents had a higher effective field goal percentage than the database average in transition, and took more attempts in transition than the database average.

First, let's look at the effective field goal percentage in transition for Texas' opponents. Texas' opponents shot the lights out from three point range in the first 10 seconds of a possession. 38% of the shots attempted against Texas early in possessions were three point attempts, and Texas' opponents made 43% of these threes, which is good for an effective field goal percentage of 64%. The database average for three point field goal percentage taken in the first 10 seconds of a possession is 35%. It is hard to say how much of this difference is due to poor transition defense by Texas, good shooting by Texas' opponents, or simply bad luck. There is a high degree of randomness involved. Texas' opponents took 184 three point shots in transition. So the difference between Texas' allowed 3 point FG% in transition and the database average amounts to about 15 extra made three point shots, spread out over a 34 game season.

Texas also gave up a few more shots in transition than the database average. Looking at the database as a whole, one way that teams can give up a greater percentage of shots in transition can be blamed on the offense. Steals and rebounds are more likely to lead to quick transition shots than made baskets or dead ball turnovers. These factors are largely the fault of the offense. But in Texas' case, we can't really blame the greater quantity of transitions shots that they faced on the offense. Texas' opponents actually started a lower percentage of their possessions off of steals and rebounds than the database average. Instead, what we find is that no matter how the possession started, Texas' opponents shot more quickly than average. For example, Texas' opponents shot in the first 10 seconds after a made basket by Texas 19% of the time, compared with the database average value of 14% of the time. This probably reflects the preferred style of play of Texas' opponents as much as anything related to the Texas defense, but I would need to do more research on this point before concluding anything definitive. This is the problem with looking at numbers that haven't been adjusted for opponents, but adjustments in this case would require a lot of research to establish their validity.

After the first 10 seconds of a possession, Texas' field goal percentage defense was better than average. A large part of this was that Texas forced their opponents to take 44% of their initial shots as two point jump shots after the first 10 seconds of a possession, compared with the database average of 38%.

Summary and outlook

When we look back at the 2011-2012 Texas defense, we see a defense that had a few specific weaknesses. Poor defensive rebounding and a tendency to foul cost Texas points all season. Aside from this, Texas played good (but not great) field goal percentage defense, and forced a few turnovers. The most significant contribution to Texas' field goal percentage defense came from their success in limiting attempts at the rim and from three point range. Texas blocked an average percentage of shots. The addition of another shot blocker would have helped a lot. Texas was hurt some in transition, particularly by teams making an unusually high percentage of three point shots in these situations. There is good reason to believe that this three point shooting effect is a fluke, and not some sort of systemic problem, but we cannot know for sure.

Texas' defense is very likely to be better next year. Better rebounding should come from the bigger bodies arriving on campus, as well as from the development of Jaylen Bond and Jonathan Holmes as players. Fewer fouls are also a reasonable thing to expect from what will be a significantly more experienced lineup. And given the height in the incoming class of freshman, I expect that Texas will block a few more shots. If these three improvements occur, it is possible for Texas to have a top 20 defense.