One year ago, we had some fun with spreadsheets and used a number of different methods to predict the ACC Tournament. Unfortunately, the raw numbers had no way of knowing the status of Ty Lawson's ankle, so the team predicted to win about 30% of the time grabbed the title, while UNC rested for bigger fish. In the past year the number of Pomeroy Disciples has grown, and so traditional "log5" predictions of the conference tournaments can be found all across teh internets (although this one in particular, from Basketball Prospectus, is a must read).
I like to find my little niche here at the Immaculate Inning, and that means simulating the hell out of things. The method is the same as for last years' ACC tournament. This year, I used raw offensive and defensive efficiencies that were tabulated here. This means that a team did not have their stats adjusted for home games or for the strength of opponent: the only values in the stat is points scored (or allowed) per possession. Via the Pythagorean Expectation Formula (with KenPom's exponent for unadjusted efficiencies = 8.5), I calculated a team's "expected winning percentage."
To determine the chances that team A beats team B, a form of Bayes Formula is applied, which in the stat-head world has come to be known as "The log5 Method." The method could be applied to any scenario where the probability of a single outcome is desired, given the prior probability for each of two alternatives. Here, we have two teams, each with an expected winning percentage, and can calculate the probability of a .900 team beating an .800 team. If we assume that the result of each game is independent, then we can multiply probabilities together to get a team's overall probability of making a certain round.
Personally I find the method rather deterministic, in what essentially is a stochastic process. Instead, I run the tournament 1 million times and calculate the percentage of simulations n which each team makes it to each round. The results of my simulations for the 2010 ACC Tournament are below:
The spreadsheet has two tabs, one for a simulation done using stats from all games, while the other is for ACC games only. The way to read it is that each team (row) won a certain number of games (0,1,2,3, or 4) in a certain percentage of the 1 million ACC tournaments I simulated. For the top four seeds, the maximum number of wins is 3, while the other 12 teams could potentially win four games and the tournament.
Duke's chances of winning the tournament is severely if stats from the entire season are used, and they go from a near 2-to-1 favorite to not even winning a majority of simulations. Part of this has to do with the raw nature of the efficiencies; accounting for Duke's tough schedule (and it was one of the toughest in the country by most any measure: KenPom, Sagarin, RPI) would probably account for most of the discrepancy.
On the other end of the spectrum is Miami, which gained an incredibly high percentage (from 0.1% to 3.4%) because they had a highly positive efficiency margin for all games, while it was highly negative in ACC games only. The Canes played very very well against a bunch of schools I've barely heard of, followed by getting clobbered in ACC play. Their adjusted efficiency margin is still decent due to the ACC games they played, but it's hard to give the full season stats much regard in this instance.
The numbers for the ACC-only simulations differ from those seen at Basketball Prospectus; I imagine most of the differences here also have to do with using raw efficiencies rather than Pomeroy's adjusted numbers. The adjusted numbers, Pomeroy claims, are the best for predicting "the chance of beating an average D-1 team on a neutral floor." The raw numbers, then, are skewed based on home-court advantage, schedule (remember, the ACC is no longer "balanced"), and the overall strength of offenses and defenses a team faces. In particular the predictions differ in that Maryland's chances are reduced, at the expense of better chances for FSU and VPI. Both methods agree that fifth-seed Wake has one hellish path towards an ACC title; much worse than sixth-seeded Clemson's chances. Overall, it will be interesting to see whether raw or adjusted efficiencies do a better job predicting the ACC tournament.
Another advantage that these simulations have is the amount of fun I can have with the results. Below I present the "Fan Anxiety Matrix." Each cell in the Matrix represents the chances that a team (in the rows) loses in the ACC tournament to a specific team (in the columns):
So, Duke's "Fan Anxiety Matrix" says that, in the 37% of simulations when they didn't win the whole thing, the most common opponent taking down the Blue Devils was Maryland (Using the ACC stats here). Perhaps no surprise there, but then there were still 8.3% of the simulations in which the Blue Devils fell in the semi-finals to Virginia Tech. Duke's first round game is against either Boston College or Virgina, and the combined percentage of simulations in which the Blue Devils' ACC run ended against those two teams was six percent. It should be of some comfort that UNC's chances of taking down Duke (this would have to be in the finals) clocked in at a tiny 0.029%.
Looking at the matrix, Clemson's path is an interesting one. The Tigers are seeded sixth and must at least pass through NCSU and FSU to get to the semifinals; the Matrix has them losing to these teams 22.5% and 37.1%, respectively. Maryland (22.4%) and Duke (10.1%) also appear in the double-digit percentages as Clemson's final ACC foe, with the remaining 3.2% speaking for Clemson's ACC title chances.
Virginia Tech's bubble position would certainly be helped with a win in their quarterfinal matchup; things are looking up according to the simulations, which have them falling to Duke in the semifinals 50% of the time. Wake Forest has a rough road to the ACC title, as they must win Thursday versus Miami (losing %: 30.5), Friday versus Virginia Tech (39.5%), Saturday versus (with 94% probability) Duke, who accounted for a further 25% of Wake's losses in the simulations.
For posterity's sake, here are the official Immaculate Inning ACC Tournament Predictions:
Thursday winners: Virginia, Wake Forest, Georgia Tech, Clemson
Friday winners: Duke, Virginia Tech, Maryland, Clemson
Saturday winners: Duke, Maryland
ACC Champion: Duke 75, Maryland 60
Showing posts with label ACC Tournament. Show all posts
Showing posts with label ACC Tournament. Show all posts
Thursday, March 11, 2010
Friday, March 13, 2009
Updated ACC Tourney Probabilities
With the first six games in the ACC Tournament complete, let's revisit the log5 predictions, which are based on tempo-free efficiency ratings accrued in ACC games only:
These are up to date following FSU's escape of Georgia Tech in the second afternoon game. As you can see, North Carolina has increased their chances of winning the tournament to better than 50/50. Duke's tournament chances have actually gone down, caused by no longer having the possibility of playing Virginia. Both of tonight's quarterfinal games have a similar 4-to-1 advantage for favorites Duke and Wake Forest. Maryland doesn't have much of a chance of winning the tournament, but should they pull the upset tonight, would that be enough to get the ACC a seventh team in Teh Dance?
The other story lines remaining in the ACC tournament are all about seedings. Carolina probably locked up their #1 seed with a win, considering that they're actually still playing, unlike UConn, Pitt, and Oklahoma. The ACC results are not in a vaccuum, the seedings of Duke and Wake are heavily influenced by the results of the other tournaments. For example, someone upsetting Memphis or Louisville capturing the Big East tournament would have top-seeded implications.
Stay tuned to Immaculate Inning for all your March Madness projection needs. We've got a big project in the works to unveil late Sunday or early Monday. NCAA Hoops- Awesome!
These are up to date following FSU's escape of Georgia Tech in the second afternoon game. As you can see, North Carolina has increased their chances of winning the tournament to better than 50/50. Duke's tournament chances have actually gone down, caused by no longer having the possibility of playing Virginia. Both of tonight's quarterfinal games have a similar 4-to-1 advantage for favorites Duke and Wake Forest. Maryland doesn't have much of a chance of winning the tournament, but should they pull the upset tonight, would that be enough to get the ACC a seventh team in Teh Dance?
The other story lines remaining in the ACC tournament are all about seedings. Carolina probably locked up their #1 seed with a win, considering that they're actually still playing, unlike UConn, Pitt, and Oklahoma. The ACC results are not in a vaccuum, the seedings of Duke and Wake are heavily influenced by the results of the other tournaments. For example, someone upsetting Memphis or Louisville capturing the Big East tournament would have top-seeded implications.
Stay tuned to Immaculate Inning for all your March Madness projection needs. We've got a big project in the works to unveil late Sunday or early Monday. NCAA Hoops- Awesome!
Labels:
ACC Tournament,
predictions
Wednesday, March 11, 2009
ACC Conference Play: Devourer of Stats
A few weeks ago, I made a very critical post about the 2008-2009 Duke team. Having come off of a very poor stretch, the once promising Blue Devils seemed to be succumbing to conference play, with disastrous consequences. I concluded that Duke's pounding of non-conference foes was clouding our view of their standing, statistically speaking. Pomeroy's rankings simply cannot account for the evolution of a team throughout a season; they treat a November blowout win the same as a February blowout win. And conventional wisdom would treat the latter as more indicative of a team's chances in March.
With the ACC season complete I thought I'd take one final look at Duke's performance between conference and non-conference play. The result is not pretty:
In red are all the categories in which Duke is performing worse in ACC play compared to out of conference play (this includes 2009 games against Davidson, Georgetown, and St. John's). With the exception of turnovers on offense, Duke is not playing as well. But clearly, the level of play in the ACC must affect all teams. So I then tallied up every team's tempo-free performances. Rather than post another spreadsheet, the results can be found here. Some major points:
1) Nearly team saw both their offensive and defensive efficiencies drop when they were playing against ACC opponents. In fact, nearly every cell in the "Difference" part of my spreadsheet is colored red, meaning teams were also worse in other statistical categories. This probably makes sense, since the ACC is ranked the #1 conference by Pomeroy, and the #1 conference by Sagarin.
2) Overall, offense was less affected than defense. During ACC play, the conference teams averaged an efficiency of 104.5. Compared to the national average (100.1), it means that the ACC has an offense-heavy atmosphere. It would take further analysis to prove this point, but I believe this could have an effect similar to the "ballpark effect" in baseball; if the Oakland A's hit 300 home runs as a team, it would be more impressive than if the Colorado Rockies did it. By analogy I am suggesting that having a good offense in the ACC is not as impressive as having a good defense. This points a praising finger squarely at teams like FSU and Duke, the only teams to have defensive efficiency ratings below 100 during conference play.
3) Florida State is a major exception. While everyone elses' offensive efficiency was dropping, Florida State actually improved their offensive efficiency in conference play. A large part of this comes from another category-- turnover rate. Along with Duke, the Seminoles are one of two teams to improve their turnover rate on offense against ACC foes. Their effective field goal percentage and offensive rebounding rate were not as affected by conference play as well.
4) NC State is probably the biggest culprit of Cupcake Syndrome. The Wolfpack's offensive efficiency dropped by 8.4 points in ACC play (the worst drop the conference), and their defensive efficiency also dropped, by 18.0 points. They were an average team until January, and simply not a very good team in conference play.
5) There is no evidence for the conception "The ACC refs call more fouls than the rest of the nation." Collectively, the ACC teams went to the charity stripe during 35.4% of their possessions during league play, compared to 41.4% of possessions in non-conference play. While free throw rate is not a perfect proxy for the number of fouls called, it is obvious that the the ACC refs aren't as whistle happy as some would have you believe. On the other hand, during non-conference play, the opponents of ACC teams went to the free throw line in just 30.0% of possessions. There is certainly a connection between level of play and the number of fouls called; bad teams have bad defensive positioning and would tend to be whistled more often.
6) Continuing on the foul theme, Duke was near the top of free throw rate in conference (39.9%, 4th) and out of conference (46.2%, 3rd), but by no means any fuel for the DukeGetsAllTheCalls morons. In fact, every team (including Duke) saw their opponents go to the free throw line more frequently during ACC play, except one. That would be the Carolina Tar Heels, who inexplicably allowed free throws on 4% fewer possessions, compared to out of conference play. I'm not suggesting conspiracy, it's probably due to their Swiss cheese approach to half-court defense...
7) Wake Forest's defensive woes may be a bit misleading. Sure, they saw the biggest drop in defensive efficiency (19 points) of any team in the league. But, during league play they still have the best defensive effective field goal percentage, and the best defensive rebounding rate, of any team in the ACC. In this case, I'm guessing the problem was a cupcake pre-conference schedule (ranked 275th by Pomeroy), rather than some exposure by better competition.
8) Finally, we return to the most overanalyzed team in the country: Duke. It's amusing to me that any casual college basketball fan in the country right now can point to seven different reasons why the Blue Devils are not poised for greatness: they lack depth, they can't stop quick guards, they can't stop an inside presence, they don't play enough zone, they don't adapt in-game, ad nauseum. I wonder if those fans can note weaknesses so easily in other top 10 teams? Still, even I was receptive to this line of thinking a few weeks ago. But my comparison is clear: Duke is in the middle of the pack when it comes to their statistics being "affected" somehow by non-conference play.
In fact, contrary to my conclusions a few weeks ago, Duke's defense is one of the least affected by ACC play. On offense, Duke turns the ball over less frequently than any ACC team, and have respectable rebounding numbers for a team with "no inside presence." The lesson: stop making judgments in a vaccum; statistics can be misleading if they are not in a relative context.
With the ACC season complete I thought I'd take one final look at Duke's performance between conference and non-conference play. The result is not pretty:
In red are all the categories in which Duke is performing worse in ACC play compared to out of conference play (this includes 2009 games against Davidson, Georgetown, and St. John's). With the exception of turnovers on offense, Duke is not playing as well. But clearly, the level of play in the ACC must affect all teams. So I then tallied up every team's tempo-free performances. Rather than post another spreadsheet, the results can be found here. Some major points:
1) Nearly team saw both their offensive and defensive efficiencies drop when they were playing against ACC opponents. In fact, nearly every cell in the "Difference" part of my spreadsheet is colored red, meaning teams were also worse in other statistical categories. This probably makes sense, since the ACC is ranked the #1 conference by Pomeroy, and the #1 conference by Sagarin.
2) Overall, offense was less affected than defense. During ACC play, the conference teams averaged an efficiency of 104.5. Compared to the national average (100.1), it means that the ACC has an offense-heavy atmosphere. It would take further analysis to prove this point, but I believe this could have an effect similar to the "ballpark effect" in baseball; if the Oakland A's hit 300 home runs as a team, it would be more impressive than if the Colorado Rockies did it. By analogy I am suggesting that having a good offense in the ACC is not as impressive as having a good defense. This points a praising finger squarely at teams like FSU and Duke, the only teams to have defensive efficiency ratings below 100 during conference play.
3) Florida State is a major exception. While everyone elses' offensive efficiency was dropping, Florida State actually improved their offensive efficiency in conference play. A large part of this comes from another category-- turnover rate. Along with Duke, the Seminoles are one of two teams to improve their turnover rate on offense against ACC foes. Their effective field goal percentage and offensive rebounding rate were not as affected by conference play as well.
4) NC State is probably the biggest culprit of Cupcake Syndrome. The Wolfpack's offensive efficiency dropped by 8.4 points in ACC play (the worst drop the conference), and their defensive efficiency also dropped, by 18.0 points. They were an average team until January, and simply not a very good team in conference play.
5) There is no evidence for the conception "The ACC refs call more fouls than the rest of the nation." Collectively, the ACC teams went to the charity stripe during 35.4% of their possessions during league play, compared to 41.4% of possessions in non-conference play. While free throw rate is not a perfect proxy for the number of fouls called, it is obvious that the the ACC refs aren't as whistle happy as some would have you believe. On the other hand, during non-conference play, the opponents of ACC teams went to the free throw line in just 30.0% of possessions. There is certainly a connection between level of play and the number of fouls called; bad teams have bad defensive positioning and would tend to be whistled more often.
6) Continuing on the foul theme, Duke was near the top of free throw rate in conference (39.9%, 4th) and out of conference (46.2%, 3rd), but by no means any fuel for the DukeGetsAllTheCalls morons. In fact, every team (including Duke) saw their opponents go to the free throw line more frequently during ACC play, except one. That would be the Carolina Tar Heels, who inexplicably allowed free throws on 4% fewer possessions, compared to out of conference play. I'm not suggesting conspiracy, it's probably due to their Swiss cheese approach to half-court defense...
7) Wake Forest's defensive woes may be a bit misleading. Sure, they saw the biggest drop in defensive efficiency (19 points) of any team in the league. But, during league play they still have the best defensive effective field goal percentage, and the best defensive rebounding rate, of any team in the ACC. In this case, I'm guessing the problem was a cupcake pre-conference schedule (ranked 275th by Pomeroy), rather than some exposure by better competition.
8) Finally, we return to the most overanalyzed team in the country: Duke. It's amusing to me that any casual college basketball fan in the country right now can point to seven different reasons why the Blue Devils are not poised for greatness: they lack depth, they can't stop quick guards, they can't stop an inside presence, they don't play enough zone, they don't adapt in-game, ad nauseum. I wonder if those fans can note weaknesses so easily in other top 10 teams? Still, even I was receptive to this line of thinking a few weeks ago. But my comparison is clear: Duke is in the middle of the pack when it comes to their statistics being "affected" somehow by non-conference play.
In fact, contrary to my conclusions a few weeks ago, Duke's defense is one of the least affected by ACC play. On offense, Duke turns the ball over less frequently than any ACC team, and have respectable rebounding numbers for a team with "no inside presence." The lesson: stop making judgments in a vaccum; statistics can be misleading if they are not in a relative context.
Labels:
ACC Tournament,
Duke,
Pomeroy Stats
Monday, March 09, 2009
2009 ACC Tournament Predictions
Some of the hardest days as a sports fan come during early March; the worst of all are the four days between Selection Sunday and the first full day of NCAA tournament games. For this ACC fan, it is equally hard to bear the four days between the Duke-Carolina rematch and the start of the ACC tournament. Sure, there are plenty of actual games between now and then, but few of them actually matter, save the random upset of a top 25 mid-major and the corresponding bubble implications. To pass the time, I repeated an exercise I completed two years ago this week: predictions for the ACC tournament using the log5 method.
There will no doubt be predictions using Ken Pomeroy's rating system, all over the internet. (Here's one simple example.) I want to do something different; how do the predictions change, based on whether I use:
1) Winning Percentage
2) Raw Points Scored/Allowed
3) Pomeroy's Rankings (Full Season)
4) Raw Efficiency (ACC Games Only)
What follows are four Google spreadsheets tallying the information. Each sheet has three tabs: the calcuated winning percentage for each team. For tests 2 through 4, my formula follows Ken Pomeroy's: PF^11.5/(PF^11.5+PA^11.5). The next tab shows the chances that the team in a given column will beat the team listed in a row, using the "log5" formula, discussed here. Finally, mindful of the ACC Tournament Bracket, I predict each team's chances to advance to the Quarterfinals, Semifinals, Finals, and their chances of being 2009 ACC Champion. Let's start with raw winning percentage.
So you can see that Duke has an .806 winning percentage, a 31.6% chance of beating UNC, and a 15. 6% chance of winning the ACC tournament. Of course, winning percentage is kind of silly, because blowouts and squeakers count exactly the same. For this reason many baseball stat-heads turned to Pythagorean Win Percentage, which calculates a team's likely winning percentage given how much they score and how much they allow. This can be applied to basketball as well, with the following result:
Some pretty big changes already. First off, Duke has vaulted above Wake and is now favored to make the finals against a still-overwhelmingly-favored UNC team. The middle of the pack has changed considerably; Miami has doubled their chances, while Clemson has had theirs halved. We know that the Pythagorean Winning Percentage is flawed, Baseball Prospectus also follows what they call "Third Order Wins." By this they mean that how much offense/defense is not as important as the context in which the points were scored.To put it in 2009 terms, which team has the better offense:
VMI-- Points/Game: 93.8 Possessions/Game: 81.2
Duke- Points/Game: 78.7 Possessions/Game: 70.1
It is true that VMI scores 15 more points per contest than the Blue Devils; they are the most prolific scorers in the nation. However, VMI plays at the fastest tempo in the country, getting over 11 possessions more per game than Duke. Teams play different opponents every game, which could have a wide variance in the number of possessions. So, a fair comparison of offenses requires looking not at a team's raw scoring numbers, but at how efficiently a team scores in the possessions it gets. With this, it is clear that Duke has the better offense.
So what if we were to predict the results of the ACC tournament using Offensive and Defensive Efficiency, as provided by Ken Pomeroy? For this run I will also take each team's schedule into account by using Pomeroy's "Adjusted" efficiency ratings; teams are penalized if they run up high efficiencies against bottom feeding teams. The results are provided in an earlier link, but I'm showing my work:
While the chances of favorite UNC have remained largely the same, the effect of tempo-free statistics and the schedule have boosted Duke's chances by 5%. Most of this comes from an ever-increasing chance of beating Wake Forest on a neutral court: from 46% using just win percentage to 56% with Pythagoras to 62% tempo-free.
Frequently, when I use these tempo-free statistics, some folks are not convinced. They think that the adjustments for schedule made by Pomeroy are not enough, and that teams are different in league play than they were playing non-league foes before the new year. In addition, the ACC tournament is taking place between only ACC teams, so shouldn't statistics within the ACC matter more? On the other hand, the ACC no longer has a balanced schedule; for example, Boston College played Duke once (at home) while they played #12 seed Georgia Tech twice. I have not attempted to adjust for schedule here, so these are raw efficiency numbers:
The most striking result is that the top three teams (UNC, Duke, Wake) have had their chances all go down, relative to the full-season Pomeroy ratings. These extra chances have been split among a few teams. Clemson's title chances went up by 3 percentage points. Florida State, whose defense has improved tremendously since the clock ticked to 2009, have doubled their title chances (as have Boston College).
NCAA Tournament Implications:
1) The 8-9 game is not the closest of the first round. That distinction belongs to NCSU vs Maryland, according to all four metrics. That is not a good matchup for anyone who thinks that Maryland is still on the bubble.
2) Virginia Tech is pretty screwed. Like Maryland, they are a 7-9 ACC team, and the committee doesn't usually take kindly to a sub-.500 conference record. They are probably out of the tournament picture unless they make it deep, and the statistics say it's not probable at all.
3) The final 7-9 team, Miami, has to avoid a collapse against Virginia Tech, and then they face 2-to-1 odds against in the matchup with Wake Forest. Should they prevail, would the committee consider what then would be a 20-win ACC team?
4) Statistically, the top three seeds are very heavy favorites for the semifinals, with Duke and UNC more likely to be there than Wake. Should Duke win the two games as expected, would they still have to beat Wake Forest to get a #2 seed in the NCAAT? Certainly, the Deacons probably need to win the ACC tournament to get their own #2 seed.
5) Clemson and Florida State should both be solidly into the NCAA tourament, but they are playing for favorable seedings. By the ACC numbers and the overall Pomeroy ratings, Clemson is favored in a matchup with Florida State, and the Tigers are more likely to knock off UNC.
6) Spreadsheets are fun!
There will no doubt be predictions using Ken Pomeroy's rating system, all over the internet. (Here's one simple example.) I want to do something different; how do the predictions change, based on whether I use:
1) Winning Percentage
2) Raw Points Scored/Allowed
3) Pomeroy's Rankings (Full Season)
4) Raw Efficiency (ACC Games Only)
What follows are four Google spreadsheets tallying the information. Each sheet has three tabs: the calcuated winning percentage for each team. For tests 2 through 4, my formula follows Ken Pomeroy's: PF^11.5/(PF^11.5+PA^11.5). The next tab shows the chances that the team in a given column will beat the team listed in a row, using the "log5" formula, discussed here. Finally, mindful of the ACC Tournament Bracket, I predict each team's chances to advance to the Quarterfinals, Semifinals, Finals, and their chances of being 2009 ACC Champion. Let's start with raw winning percentage.
So you can see that Duke has an .806 winning percentage, a 31.6% chance of beating UNC, and a 15. 6% chance of winning the ACC tournament. Of course, winning percentage is kind of silly, because blowouts and squeakers count exactly the same. For this reason many baseball stat-heads turned to Pythagorean Win Percentage, which calculates a team's likely winning percentage given how much they score and how much they allow. This can be applied to basketball as well, with the following result:
Some pretty big changes already. First off, Duke has vaulted above Wake and is now favored to make the finals against a still-overwhelmingly-favored UNC team. The middle of the pack has changed considerably; Miami has doubled their chances, while Clemson has had theirs halved. We know that the Pythagorean Winning Percentage is flawed, Baseball Prospectus also follows what they call "Third Order Wins." By this they mean that how much offense/defense is not as important as the context in which the points were scored.To put it in 2009 terms, which team has the better offense:
VMI-- Points/Game: 93.8 Possessions/Game: 81.2
Duke- Points/Game: 78.7 Possessions/Game: 70.1
It is true that VMI scores 15 more points per contest than the Blue Devils; they are the most prolific scorers in the nation. However, VMI plays at the fastest tempo in the country, getting over 11 possessions more per game than Duke. Teams play different opponents every game, which could have a wide variance in the number of possessions. So, a fair comparison of offenses requires looking not at a team's raw scoring numbers, but at how efficiently a team scores in the possessions it gets. With this, it is clear that Duke has the better offense.
So what if we were to predict the results of the ACC tournament using Offensive and Defensive Efficiency, as provided by Ken Pomeroy? For this run I will also take each team's schedule into account by using Pomeroy's "Adjusted" efficiency ratings; teams are penalized if they run up high efficiencies against bottom feeding teams. The results are provided in an earlier link, but I'm showing my work:
While the chances of favorite UNC have remained largely the same, the effect of tempo-free statistics and the schedule have boosted Duke's chances by 5%. Most of this comes from an ever-increasing chance of beating Wake Forest on a neutral court: from 46% using just win percentage to 56% with Pythagoras to 62% tempo-free.
Frequently, when I use these tempo-free statistics, some folks are not convinced. They think that the adjustments for schedule made by Pomeroy are not enough, and that teams are different in league play than they were playing non-league foes before the new year. In addition, the ACC tournament is taking place between only ACC teams, so shouldn't statistics within the ACC matter more? On the other hand, the ACC no longer has a balanced schedule; for example, Boston College played Duke once (at home) while they played #12 seed Georgia Tech twice. I have not attempted to adjust for schedule here, so these are raw efficiency numbers:
The most striking result is that the top three teams (UNC, Duke, Wake) have had their chances all go down, relative to the full-season Pomeroy ratings. These extra chances have been split among a few teams. Clemson's title chances went up by 3 percentage points. Florida State, whose defense has improved tremendously since the clock ticked to 2009, have doubled their title chances (as have Boston College).
NCAA Tournament Implications:
1) The 8-9 game is not the closest of the first round. That distinction belongs to NCSU vs Maryland, according to all four metrics. That is not a good matchup for anyone who thinks that Maryland is still on the bubble.
2) Virginia Tech is pretty screwed. Like Maryland, they are a 7-9 ACC team, and the committee doesn't usually take kindly to a sub-.500 conference record. They are probably out of the tournament picture unless they make it deep, and the statistics say it's not probable at all.
3) The final 7-9 team, Miami, has to avoid a collapse against Virginia Tech, and then they face 2-to-1 odds against in the matchup with Wake Forest. Should they prevail, would the committee consider what then would be a 20-win ACC team?
4) Statistically, the top three seeds are very heavy favorites for the semifinals, with Duke and UNC more likely to be there than Wake. Should Duke win the two games as expected, would they still have to beat Wake Forest to get a #2 seed in the NCAAT? Certainly, the Deacons probably need to win the ACC tournament to get their own #2 seed.
5) Clemson and Florida State should both be solidly into the NCAA tourament, but they are playing for favorable seedings. By the ACC numbers and the overall Pomeroy ratings, Clemson is favored in a matchup with Florida State, and the Tigers are more likely to knock off UNC.
6) Spreadsheets are fun!
Labels:
ACC Tournament,
Duke,
predictions
Wednesday, March 07, 2007
ACC Tournament Predictions
The ACC tournament starts tomorrow, and many sites are awash with predictions. The best conference in the land is rife with parity, and this weekend will truly be Madness. One way to predict the tournament scientifically is to use the offensive and defensive efficiencies you've read about here all season. Ken Pomeroy has done just that, using the data from each team's entire season of work.
The principle is based on the Pythagorean Winning Percentage. To explain again, each team can be expected to win a certain percentage of games based on its offense and defense. In baseball this is done with runs scored/allowed; here we are using offensive and defensive efficiencies. I wanted to look at whether the results would be different if only ACC games were considered. That data is available here, thanks to the great work of Paul Rugani. After getting each team's Pythag WinPct, we can then predict how team A would fare against team B: (A-AB)/(A+B-2AB). Then based on potential matchups in the ACC tournament, we can calculate the chances that each team reach each round:
Again, this is based entirely on ACC games. Duke's chances of winning the tournament are severely depressed compared to Pomeroy's prediction, due to Duke's relatively worse defense in ACC play. The increased chances of UVA, VT, and Duke compared to the rest of the bracket have to do with how long each team has to wait to play the overwhelming favorite- UNC.
This seems like a good place for my predictions. Maryland is one of the most under-seeded teams in this tournament, and has the best chances of knocking of UNC. I don't see any of the slower-pace, short-bench teams (like FSU, Clemson, or BC) upsetting UNC, so I'll pick Maryland to reach the finals. Duke, meanwhile, is similarly under-seeded, and could make quick work of NCSU before revenging themselves upon UVA. A matchup with either Virginia Tech or Georgia Tech likely sits next. If it's Georgia Tech, I like Duke- Virginia Tech is a much tougher game. Duke will have trouble against either UNC or Maryland in the final, and so I think whoever emerges from the 1-4 side of the bracket should win the tournament.
What I think these stats show more than anything is that Duke is not to be counted out of this tournament simply because of a low seed. Whatever happens, it will be fun to watch. Any other predictions?
The principle is based on the Pythagorean Winning Percentage. To explain again, each team can be expected to win a certain percentage of games based on its offense and defense. In baseball this is done with runs scored/allowed; here we are using offensive and defensive efficiencies. I wanted to look at whether the results would be different if only ACC games were considered. That data is available here, thanks to the great work of Paul Rugani. After getting each team's Pythag WinPct, we can then predict how team A would fare against team B: (A-AB)/(A+B-2AB). Then based on potential matchups in the ACC tournament, we can calculate the chances that each team reach each round:
Again, this is based entirely on ACC games. Duke's chances of winning the tournament are severely depressed compared to Pomeroy's prediction, due to Duke's relatively worse defense in ACC play. The increased chances of UVA, VT, and Duke compared to the rest of the bracket have to do with how long each team has to wait to play the overwhelming favorite- UNC.
This seems like a good place for my predictions. Maryland is one of the most under-seeded teams in this tournament, and has the best chances of knocking of UNC. I don't see any of the slower-pace, short-bench teams (like FSU, Clemson, or BC) upsetting UNC, so I'll pick Maryland to reach the finals. Duke, meanwhile, is similarly under-seeded, and could make quick work of NCSU before revenging themselves upon UVA. A matchup with either Virginia Tech or Georgia Tech likely sits next. If it's Georgia Tech, I like Duke- Virginia Tech is a much tougher game. Duke will have trouble against either UNC or Maryland in the final, and so I think whoever emerges from the 1-4 side of the bracket should win the tournament.
What I think these stats show more than anything is that Duke is not to be counted out of this tournament simply because of a low seed. Whatever happens, it will be fun to watch. Any other predictions?
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ACC Tournament
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