Do Matchups Matter?

The following is my entry for Stat Geek Idol. The contest is run by TeamRankings.com. Check out some of the entries from last year's competition here.

Introduction:

There are 347 teams in Division I college basketball. The nature of the sport allows for all different kinds of styles of play. Every team has varying player personnel and coaching philosophy. College basketball analysts are given the tough task of forecasting the end result of games featuring contradicting styles. It seems undeniable that, in some cases, certain teams can be bad matchups for other teams. Still, quite frequently analysts just say what sounds good. To illustrate this point, let’s look at a first round matchup from this year’s NCAA tournament:

The four factors (shooting, rebounding, taking care of the ball, and drawing fouls) are a very good way to assess style of play. The Minnesota-UCLA matchup featured the best offensive rebounding team in the country (Minnesota) and the 263rd defensive rebounding team in the country (UCLA). A smart analyst would point this compatible Minnesota strength and UCLA weakness out, but what does it really mean for the expected outcome of a game? On one hand, Minnesota should kill UCLA on the offensive boards, possibly creating a huge advantage for Minnesota. On the other hand, Minnesota kills just about everyone on the offensive boards. UCLA wouldn't be able to stop the lethal Minnesota rebounding attack regardless, so maybe this is a waste of an opponent weakness for Minnesota.

Essentially, the question I am asking here is simply: If you are really good at one of the four factors, would you rather play a team that is normally good at defending that factor (strength on strength) or really bad at defending that factor (strength on weakness)? At first thought, strength on weakness feels like the right choice. The goal of the following analysis is to try to answer this question.

Part 1: The effects of opponent on each four factor

To begin this study, I compiled a sample size of every single Division I college basketball game from 2009, 2010, 2011, and 2012. Games from 2013 (up until around the first week of March) were also included. I wound up with exactly 26,000 games to draw conclusions from.

In order to look at what happens when a {good/bad} offensive {eFG/TO/OR/FTR} team played a {good/bad} defensive {eFG/TO/OR/FTR} team, I had to define what exactly good or bad means. I decided that any team in the 90th percentile or better of a given four factor was “good” at that skill and any team in the 10th percentile or worse of a given four factor was “bad” at that skill.

NOTE: Good/bad is just the opposite for defense (i.e. - you want your opponent’s eFG% to be low)

The next step was to use these definitions of good and bad to find instances of strengths meeting strengths, weaknesses meeting weaknesses, and so on in the 26,000 game sample. First, let’s take a look at what happens when a good shooting team plays a good defensive shooting team:

The above table shows that there were 409 games where a good offensive eFG% team played a good defensive eFG% team. The offense averaged an eFG% of 54.5% on the season. However, when they played a good eFG% defense, that number decreased to 49.8%.

I did this same analysis for all types of matchups and all the four factors. The results are below:

There is a lot going on here, but the two biggest takeaways are:

1. Bad vs. bad brings out more good than good vs. good brings out bad. Basically, when two bad teams at one factor play each other, the offense improves a lot. When two good teams at one factor play each other, the offense does not diminish quite as much.

2. The defense controls FTR the most and eFG% the least. If you look at the percent change column, an offenses ability to get to the foul line changed a lot depending on the defense. On the other hand, an offenses ability to make shots did not change nearly as much. This is consistent with past research on similar topics.

Part 2: The effects of style on efficiency

Part 1 showed exactly what happens to the individual four factor based on opponent, but that is only so helpful in determining if there is evidence for good/bad matchups. The more important thing to look at is the effects of style on points per possession. Let’s go back to UCLA-Minnesota. Say UCLA decided that they needed to make an extra effort to keep Minnesota off the offensive glass. This decision might come at the risk of a different four factor. Maybe UCLA focusing on defensive rebounding diminishes their ability to create turnovers. This idea wouldn’t show up in the part 1 results, but it would show up in points per possession.

To look at the effects of efficiency, I first calculated an expected points per possession using simply the ORtg (adjusted for schedule) of the offense and the DRtg (adjusted for schedule) of the defense. This expected PPP was made without looking at matchups or style of play at all. Then, the expected PPP could be compared to the actual PPP. If the two numbers significantly differ, that means that mismatches in four factors can give us more information on which team will most likely win the game.

As you can see, matchups had virtually no effect on the actual points per possession of the game. I was able to predict PPP by simply using the offensive and defensive averages extremely effectively. Here are the final key takeaways from the tables above.

1. Four factor matchups don’t increase prediction accuracy. If we once again go back to Minnesota-UCLA, this means that we shouldn’t have looked too far into the offensive rebounding advantage. Simply looking at which team is better efficiency wise is adequate.

2. FTRate had very little effect on the points per possession of an offense. If you look at the Actual PPP column, there is not much change in general. This particular study indicates the eFG% is the most important four factor, followed by OR%, TO%, and finally FTR.

Conclusion

It would be foolish to say that specific matchups have no effect on the outcome of a basketball game. It doesn't mean that matchups can’t possibly matter just because this study shows no evidence for it. However, the study does indicate that it may not be wise to focus too much on the compatibility of the strengths and weaknesses of opponents. Trying to breakdown strength and weaknesses may be a futile activity. Simply put, the best way to predict the winner of a game appears to be just picking the better of the two teams.

Shabazz's Rebounding

Shabazz Muhammad's season ended on Friday at the hands of Minnesota. The Bruins had two big things working against them: the injury to Jordan Adams and the task of keeping Minnesota off the boards. The Golden Gophers are first in the country in offensive rebound percentage, grabbing 44% of their missed shots. On the other hand, UCLA has struggled all season long with rebounding. They rank 206th in the country in offensive rebounding and 264th in the country in defensive rebounding. At 6'6", Shabazz's personal OReb% was a solid 9.9%, but his DReb% was an awful 8.5%. To put that into perspective, Gonzaga's 5'11" David Stockton's was higher this season (9.2%).

Trying to keep Minnesota off the offensive glass had to have been a main priority for Ben Howland on Friday. The Bruins as a whole actually did a pretty good job of this. Minnesota had 10 offensive rebounds (32.4% OReb%, well below their season average). Still, if you look at the box score you will see that Shabazz had ZERO defensive rebounds in 39 minutes. That's actually pretty hard to do, you would think a ball is going to fall in your lap at some point in the game. 

How does an athletic 6'6" forward not get a single defensive rebound in 39 minutes? Well to answer that question I decided to go back and look at the film. Of Minnesota's 10 offensive rebounds, Shabazz was on the court for nine of them. The photos below highlight where Shabazz was on the court when Minnesota got their nine rebounds.

1. In good position but flat footed, spectating

For Shabazz's sake, I was hoping the reason for his lack of rebounding was to leak out in transition. Although this might not be an optimal strategy, it would mean there is at least an advantage to his lack of rebounding. Otherwise, Shabazz is simply very bad at the skills involved in rebounding or not hustling (or both). This first attempt shows a flat footed Shabazz under the hoop. In his defense, he has three UCLA teammates in the paint with him.

2. Boxing out

The problem with this analysis is we can't be sure of Howland's gameplan. Basketball purists are quick to teach the box out, but the fact is that's much easier said than done against Minnesota. Still, I think it's safe to say that Shabazz did a pretty good job on this possession

3. Late getting back in transition

Here Minnesota got an easy put back in transition off of Shabazz's miss on the other end. He was very late getting back, but we're not too concerned about this one in terms of rebounding ability.

4. Sort of boxing out the shooter

Shabazz was guarding the initial shooter on this one. He didn't box out immediately, but at least tried to recover after he realized the ball wasn't going in.

5. Flat footed, spectating

The ball doesn't go to Shabazz's side, but he is still pretty much just standing and watching the play unfold. This is an example of the worst scenario for Shabazz. There are obviously very few times in a basketball game where standing and watching isn't a bad thing.

6. Elevating for the rebound 

Shabazz gets his hand on this ball, but was not able to come up with it. The ball got batted out for a long rebound. By getting his hand on the ball, he may have prevented  an easy layup for Minnesota (even though they were still able to maintain possession).

7. Flat footed, spectating

Another negative play for Shabazz. He's not boxing out or going after the ball. He's not even leaking out, he's just standing and watching.

8. In good position but flat footed, spectating

More of the same here.

9. A bit more of pursuit

Shabazz took steps towards the basket to potentially grab a rebound, but the ball bounced off the rim hard. You can see in the photo he is changing his momentum to either try to continue to pursue the ball or possibly to leak out.

Obviously, this analysis is only nine plays from one game and is by no means definitive. I'll let the film speak for itself and not over generalize, but Shabazz's rebounding (and motor) might be a long term concern for his NBA career. Statistically, his rebounding numbers are somewhat similar to DeMar DeRozan. DeRozan was a pretty good offensive rebounder and a not so good defensive rebounder, but not quite as bad as Shabazz.

Minnesota and Rebounds: The Art of Cherry Picking

Last month, I looked at Bucknell and turnovers in college basketball strategy. Another interesting team in the 2013 season has been Tubby Smith's Minnesota team. The Golden Gophers rolled through non conference play, but are just 8-9 in the Big Ten. Despite the struggles, Minnesota is still 16th in efficiency in the country largely due to a ridiculous offensive rebounding percentage.

Minnesota ranks first in the OReb% by a wide margin and just 239th in DReb%. Offensive and defensive rebounding aren't exactly the same skill by any means, but it doesn't make sense that a team would be so far off in the two categories. Instead, I think that the large difference is more a product of the coach's system. Here are the two schematic possibilities for Minneosta's differential.

1. Cherry picking - Minnesota is great at rebounding, but they decide to cherry pick (get out in transition) instead of having everyone defensive rebound.
2. Allowing cherry picking - Minnesota is not quite as good at rebounding as their OReb% indicates, but they decide to crash the glass relentlessly on offense instead of worrying about transition defense.

The point here is that there is a natural trade-off between rebounding and transition plays.

To further examine this, I first looked at teams with the biggest differentials between offensive and defensive rebounding. To do this, I took the z-score of each, meaning I found how far away a team's OReb% and DReb% are away from the NCAA averages.

The 10 teams on the left are all Minnesota-like. They are much better at offensive rebounding than defensive rebounding. This means we would expect a much higher number of transition players per game than the teams on the right. The teams on the right are conservative when it comes to rebounding (notice Bucknell again). They get back on defense instead of going for offensive rebounds and box out instead of cherry picking. In both cases, the two strategies by the teams on the right limit plays in transition.

I decided to put this theory to the test using hoop-math.com. Using the data from that site, we can see how often these teams both go in transition on offense and allow transition plays on defense. I did this by looking at the percentage of times a team shoots in 10 seconds off missed shots versus the percentage of times a team shoots in 11-35 seconds into the shot clock off missed shots.

The table above illustrates the trade-off between cherry picking and transition. The teams on the left (the cherry pickers) are in transition 42% of the time and allow transition 41% of the time. The teams on the right (the conservatives) are only in transition 32% of the time and allow transition only 35% of the time. 

To me, three things particularly stick out about individual teams from the tables above:

1. Minnesota is a weird team. It looks like the Golden Gophers are really just that good at offensive rebounding. I expected them to allow an extremely high percentage of transition plays due to crashing the boards, but it was actually the lowest of the top 10 teams at 36%.
2. Northwestern St. is the biggest cherry picker in the country. I haven't watched film, but the stats show that Northwestern St. takes a shot within 10 seconds of getting a defensive rebound 58% of the time. This was by far the highest percentage and might be a reason why Northwestern St. is the second best team in the Southland.
3. Bucknell ran a fast break once, just to see what it felt like. Yes, I think Bucknell is the most interesting team in the NCAA. Dave Paulsen's squad focuses on boxing out and holding teams to one shot. They only get out in transition on 14% of missed shots (not a typo).

For those of you statistically inclined, here are the scatter plots of the cherry pickers and non cherry pickers. You can see the r-squared values and how big of an outlier Minnesota is in all of this. Removing Minnesota increased correlation tremendously.

Cherry Pickers:

Conservatives:

Impossible is Nothing

The Siena Saints have been one of the more successful mid major teams in the last three years. What might have been the best recruiting class in school history (Ronald Moore, Edwin Ubiles, and Alex Franklin) led Siena to two NCAA Tournament victories in the last three years.

This season, much has changed for the Saints. Fran McCaffery has been replaced by Mitch Buonaguro and the three stars have graduated. Clarence Jackson and Ryan Rossiter are the go-to guys and team leaders. The point guard position is the one with the biggest question mark. Kyle Griffin started the first two games, but gave way to freshman Rakeem Brookins in game three.

So the Saints went into their second game of the season (@ Minnesota) with question marks at the point and searching for a new identity. They got off to a hot shooting start early (and by they I mean Clarence Jackson), but cooled off by the middle of the first half. Ultimately, the Saints lost 76-69. The problem for the Saints? Lots and lots of turnovers.

After the game, Coach Buonaguro said:

“It really came down to us turning the ball over,” Buonaguro continued. “I thought we outplayed Minnesota in a lot of areas, but the turnover battle was 24-15 (for Minnesota). You can’t win on 24 turnovers on the road. It’s impossible.”

Impossible is a strong word. I decided to further investigate Buonaguro's claim. Of course, winning with 24 turnovers on the road is not common by any stretch, but not impossible either. In fact, Coach Buonaguro should be very familiar with one game from last year when his claim was proven false. The 2009-2010 Siena Saints defeated Tennessee State on the road despite a ridiculous 29 turnovers. Buonaguro was an assistant coach last season.

NCAA Basketball Stats

The four factors tell the whole story. Despite 29 turnovers, this game wasn't even close. The final score was 85-69. Turnovers are certainly important (and most of the time underrated), but in this case Siena had enough talent to overcome them. Buonaguro's quote is not valid. An added stipulation might have made more sense: "You can’t win on 24 turnovers on the road against a Big Ten team." That could be something to look further into in the future.

The Calm Before the Storm

College basketball is back. The beginning of the season provides interesting matchups and early adjustments. Today there are no D1 games on the schedule, but tomorrow the games start rolling in. Teams will be finding out what they have and how they can improve. Here are the games we are looking forward to.

The Potential Red Line Upset

Georgetown @ Old Dominion

KenPom Prediction: 64-63 Georgetown

2010 Interesting Fact: Old Dominion won more NCAA Tournament games (1) than Georgetown (0)

Georgetown kicks off the season with a tough one. Last year, ODU played at a slow pace and grinded out games on defense. The mentality paid off as they defeated Notre Dame 51-50 in the first round of the NCAA Tourney. This is a rematch of the game last year at the Verizon Center. ODU won that one 61-57. Georgetown will not be looking past the Monarchs this season.

The Team with Upside

Seton Hall @ Temple

Kenpom Prediction: 71-65 Temple

2010 Interesting Fact: Seton Hall (32nd in the nation) averaged nearly 10 more possession per game than Temple (336th in the nation).

Seton Hall is a big unknown coming into the season. They have the players to be competitive in the Big East, but don't have program stability just yet. This game is another rematch from last season. In that game, Seton Hall blew an early second half lead as Temple won 71-65. Seton Hall does not have a very challenging non-conference schedule, so this will be one of the best times to get a look at them. However, Lavoy Allen and company are certainly favored at home.

The Player Worth the Price of Admission

Wofford @ Minnesota

KenPom Prediction: 70-61 Minnesota

2010 Interesting Fact: Noah Dahlman was in the top 300 in shooting (eFG), offensive rebounding (OR%), taking care of the ball (TO%), and getting to the line (FTRate). Basically, he's really good.

Wofford will have a chance to start their season with an upset at Williams Arena. Last year Wofford ended the season in the Tourney with a close loss to Wisconsin prior to winning 13 straight SoCon games in a row. Dahlman is excellent and Minnesota is an interesting team themselves. Give the SoCon some love and tune in to watch one of the best players most have never heard of.

Big Ten: 2010-11 Preview

A team to review from last year...
Minnesota

The Gophers were quietly a quality team last season. They shot the ball very well and took care of the ball. On defense, they also had success. As a result, Tubby Smith's club had a number of big wins. Minnesota defeated Butler, Ohio St., Wisconsin, Michigan St., and Purdue. Still, they struggled with consistency finish 8-8 in the Big Ten.

This season, the Gophers are a step behind the top heavy Big Ten. A couple months ago, we interviewed The Daily Gopher about Blake Hoffarber and Minnesota. The guys over there summed it up best, "There is the talent to compete for a conference title but the starts kind of have to align for that to be realistic possibility. If guys do not become eligible and Williams doesn't figure out how to get himself on the floor, this team will miss the NCAA Tournament and could finish way down in the Big Ten pecking order."


A flaw to consider...
Michigan State's turnovers

Turnovers and turnovers only are what kept Coach Izzo's club out of the top 20 in adjusted efficiency rankings. They were the problem on both offense and defense. Offensively, only two players had a TO% of under 18%. Defensively, the Spartans only caused their opponents to turn the ball over 18.7% of possessions. Michigan St. rebounded and shot the ball extremely well. However, if the Spartans are a true national title contender the turnovers will have to improve this season.


A team that will get more attention than their body of work merits...
Michigan

The expectations aren't very high for the Wolverines entering this season. Manny Harris and DeShawn Sims are gone from a team that finished just 7-11 in conference. Ballin' is a Habit has some interesting words about Michigan, "On paper, this looks like a team destined for a rebuilding year. But keep in mind, this is the kind of team that Beilein succeeds with. A bunch of scrappy underachievers willing to buy into Beilein's system." However, scrappiness is sometimes (not always) more perception than reality. Michigan probably just won't be good enough to compete this season.


A team that will get less attention than their body of work merits...
Wisconsin

The Badgers are probably the cliche team for this category. Nearly every year they fly under the radar. The Badgers play at a slow pace and are by no means flashy. With the losses of Trevon Hughes and Jason Bohannon, new names will have to emerge. Knowing Bo Ryan's team, however, new players will step up. Jordan Taylor appears ready to breakout in the backcourt. Wisconsin will almost certainly shoot the ball well, take care of the ball, and rebound defensively. With these three attributes, the Badgers seem to be a lock to contend in the Big Ten.


PLAYER OF THE YEAR: Jon Leuer, Wisconsin

Last year, Leuer had great numbers co-starring with Trevon Hughes. He shot 39% from three and 55% from two. He also had a ridiculous 8.5 TORate. The 6'10" senior will be back for part two, but minus Hughes. Leuer will not only be one of the top players in the Big Ten, but a top player nationally.

Best of the Rest:

1) Robbie Hummel, Purdue
2) Joe Shurna, Northwestern
3) Kalin Lucas, Michigan State
4) Demetri McCamey, Illinois
5) Talor Battle, Penn State
6) William Buford, Ohio State
7) Maurice Creek, Indiana


BREAKOUT PLAYER: Jordan Taylor, Wisconsin

Taylor does not fit the standard definition of a breakout player we have been using throughout the conference previews. He was third on the Badgers in minutes played. However, Taylor's role will go way up with the departures of Trevon Hughes and Jason Bohannon. As Dylan Burkhardt of umhoops.com pointed out, Taylor's sophomore season numbers were very similar to Hughes' sophomore numbers. Taylor is ready to emerge as the go-to guard for Bo Ryan.

Best of the Rest:

1) Rob Wilson, Wisconsin
2) Tyler Griffey, Illinois
3) Rodney Williams, Minnesota
4) Luka Mirkovic, Northwestern

Varying Impacts - Blake Hoffarber

A while ago, we did a post on the varying impacts an efficient basketball player can have. In order to explore this subject further, we have conducted a series of interviews. We have discussed three different types of players with team specific bloggers. This first post features an interview with The Daily Gopher (twitter: @TheDailyGopher) on Blake Hoffarber.

Hoop Vision: Blake Hoffarber was first in the nation in offensive rating. Outstanding shooting percentages and quality turnover prevention were the driving factors. Where and when did Hoffarber's shots occur in 2009-2010?

The Daily Gopher: The easy answer is that Hoffarber's shots came from behind the arc. 75.8% of his shots were threes. I'm not sure where that stat compares to the rest of SGs around the country but 5.2 three-point attempts per game compared to just 1.7 twos is a pretty significant ratio. More specifically he was most proficient in transition. The Gophers turned their opponents over at a pretty high rate, especially early in the season. Hoffarber is very good at running wide, finding an open spot on the wing and then draining the three when receiving the pass. In the half-court the Gophers really were not very good at running offensive sets to get him some open shots. His shots in the half-court set usually would come on a ball reversal when the defender would fall asleep and choose to not close out on him.

Hoop Vision: Was Hoffarber's low turnover percentage more from his overall timidness in the Gopher's offense or quality decision making?

The Daily Gopher: I'll say a little of both and a lot of neither. Hoffarber's low turnover rate is largely due to the fact that he does not put the ball on the floor that often. He is a great shooter and a great passer, but he is not athletic enough to create shots with penetration. He is smart enough to know that and rarely did he put the ball on floor, putting him in position to turn the ball over.

Hoop Vision: Hoffarber shot 47% from 3 and 59% from 2, both excellent marks. However, he shot more than three times as many 3's as 2's. How big of an impact did Hoffarber's three point efficiency have on the other Minnesota players? Did his range open up space for Westbrook, Johnson, Joseph, and company?

The Daily Gopher: Yes, yes and yes. Not only was everyone better but the Gophers were 13-1 when Hoffarber scored 11 points or more last year (19-2 over the last two years). The problem is he doesn't hit that magical 11 point mark nearly enough. For a guy with his shooting ability, he really should be more of a focal point and be taking at least two or three more shots per game. This gets back to an earlier point that the Gopher offense doesn't do nearly enough to run him off screens and run offensive sets exclusively for him. He really should not be 4th on his own team for shots attempted. When you break it down by minutes he would take a shot every 4 minutes, 7th on the team for guys over 300 minutes. Lawrence Westbrook led the team taking a shot every 2.7 minutes.

Hoop Vision: Did Hoffarber best utilize his talents in the Gopher's offense or could he have played a more prominent role while keeping his excellent efficiency?

The Daily Gopher: I think if he was more of an offensive focal point, you would obviously see his efficiency drop off a little but not by much. The thing is that defenses already focus on him at all times. So if the Gopher offense were to run more of their offense through him, it is not like defenses would adjust and spend more time trying to slow him down. They already put one of their best defenders (usually a longer and more athletic one) on him and that defender typically is not responsible for helpside defense. Maybe fatigue would be more of a factor if he is running off screens and not allowed to sit out behind the arc quite as much. But that would go both ways as his defender would be taxed more as well. In the end, the Gophers need to at least find out how much his efficiency would drop. He isn't the most athletic player on the floor and he won't create his own shots, but he is savvy. Give him the opportunity to come off screens and trust him to make good decisions with the ball. Putting the defense in more situations where someone has to choose to leave their man to guard Hoffarber or let him have an open three is exactly the kind of situations the Gopher offense needs to get itself into.

Hoop Vision: Hoffarber was not nearly as efficient during his sophomore season. His turnover percentage was 22.6% and he only shot 34% from long range. Will the tremendous strides made from sophomore to junior year remain for 2010-11 or is regression due to occur?

The Daily Gopher: His sophomore year was the abberation. I do not think you will see great statistical improvement from his JR to SR year, but I'd be shocked to see him regress to anything near his Sophomore year numbers. His sophomore year was a year where he could just never get on track. Shooters go through droughts but his was started in January and lasted through the NCAA Tournament loss to Texas.

Hoop Vision: What can we expect from Minnesota as a whole in 2010-11?

The Daily Gopher: There is plenty of talent on this roster but there are a number of question marks. Two key players are still in limbo as to whether or not they'll be playing this year, both starters and key positions for this team. Al Nolen missed half the season due to academic issues and Trevor Mbakwe missed the entire season due to pending legal issues (UPDATE). If both issues are resolved then Nolen is our starting PG and Mbakwe is our starting PF. So step one is getting everyone eligible, adding those two completely change the outlook of the 2010-11 season. After getting those guys on the roster it comes down last year's sophomores and freshman improving. The soon to be juniors are the nucleus of the team. Devoe Joseph, Ralph Sampson and Colten Iverson have all been solid but they need to be better and more consistent. Rodney Williams showed flashes of great athleticism in his freshman season but he needs to grow by leaps and bounds in his sophomore year. He is capable of being our most dynamic player but he needs to understand his role in the offense and how to play Tubby's demanding defensive system. Assuming Mbakwe and Nolen play, and assuming even just moderate improvement from the rest of the roster I believe this team will fighting to finish anywhere from 3rd to 5th in the Big Ten. There is the talent to compete for a conference title but the starts kind of have to align for that to be realistic possibility. If guys do not become eligible and Williams doesn't figure out how to get himself on the floor, this team will miss the NCAA Tournament and could finish way down in the Big Ten pecking order.