A Look at SOS and the ACCT

[pfrduke]

Since the advent of the unbalanced schedule, I've looked annually at how each team's schedule stacked up. One of the more unique aspects of the method I use is to treat the conference as if it had 24 teams, rather than 12; that is each team has a "home" and "away" version, and for the teams you play once, you only get credit for the version you play (so, for example, Duke played the "home" version of Wake and the "away" version of Boston College). So let's look at that information first (all numbers are in points per hundred possessions):


Home Team Off Def Margin
Duke 109.13 88.51 20.62
Clemson 107.80 89.75 18.04
North Carolina 105.24 89.69 15.54
Florida State 105.36 91.29 14.07
Virginia Tech 113.80 102.87 10.93
Georgia Tech 95.52 88.13 7.39
Boston College 111.24 109.72 1.53
Miami 103.14 103.11 0.03
Maryland 108.59 109.68 -1.09
NC State 109.58 111.63 -2.05
Virginia 90.41 96.71 -6.31
Wake Forest 90.72 112.25 -21.54


Road Team Off Def Margin
Duke 109.46 96.95 12.51
North Carolina 104.67 99.81 4.86
Maryland 99.19 96.90 2.29
Virginia Tech 98.56 98.30 0.25
Virginia 102.52 104.19 -1.67
Boston College 104.90 107.51 -2.61
Miami 103.77 108.55 -4.78
Clemson 97.08 102.29 -5.21
Florida State 92.89 98.82 -5.93
Georgia Tech 98.67 112.15 -13.48
NC State 96.35 109.90 -13.55
Wake Forest 85.93 116.24 -30.31

To no one's great surprise, almost everyone's better at home than on the road - in most cases by a healthy margin. Only three teams - Duke, UNC, and Virginia Tech - were better than their opponents both at home and away. Maryland and Virginia were actually better on the road than at home, and Duke's road performance deserves a healthy amount of credit - better outside of Cameron than more than half the ACC was in their own stadiums, while Clemson had the most disparate home/road results (for the second season in a row - apparently Brownell couldn't cure the Tigers' road woes). Also, these numbers underscore again just how bad Wake was - the Deacs were worse at home than any other team was on the road. Yikes.

The strength of schedule is derived from figuring out the collective offensive and defensive ratings of the 16 teams you played, with your own performance factored out (so Wake's schedule doesn't look harder because it stank, and Duke's easier because it dominated). I figured out both the offensive and defensive degree of difficulty for each team. The disparities may look small, but keep in mind that the teams averaged just shy of 1100 total possessions in ACC play this season, so a difference of 2.00 in margin is 22 points over the course of the season.

Opponent offenses, from toughest to weakest:

Opp Off
Duke 103.57
Florida State 103.42
Virginia 103.16
Miami 102.83
Wake Forest 101.99
North Carolina 101.95
Georgia Tech 101.94
Clemson 101.47
Boston College 101.22
Virginia Tech 100.99
Maryland 100.00
NC State 99.89


Opponent defenses, from toughest to weakest

Opp Def
NC State 99.54
North Carolina 99.60
Boston College 100.12
Miami 100.32
Maryland 101.19
Clemson 101.72
Virginia 102.41
Virginia Tech 102.58
Duke 102.75
Wake Forest 102.96
Georgia Tech 103.65
Florida State 103.87

These two performances come together to make the opponent's scoring margin. A perfectly average schedule would be zero - anything positive is tougher, and anything negative is easier:


O Marg
Miami 2.51
North Carolina 2.35
Boston College 1.09
Duke 0.82
Virginia 0.75
NC State 0.34
Clemson -0.25
Florida State -0.45
Wake Forest -0.97
Maryland -1.19
Virginia Tech -1.59
Georgia Tech -1.70

Virginia Tech was the beneficiary of an easy schedule (although no one had anywhere near as easy a schedule as Wake and VT last year). The Hokies only had to take on Duke, UNC, Florida State, and Clemson once each (although to their credit, they went 2-2 in those games), and played Virginia, Maryland, Wake, and Georgia Tech (4 of the bottom 5 teams) twice. Miami and UNC, by contrast, had the season's toughest schedules - both had to double dip against Duke, Clemson, and FSU; Miami's schedule ended up tougher largely by virtue of playing Virginia Tech in Blacksburg, rather than in Chapel Hill. Some of these results are skewed by just how bad Wake was - the teams that doubled up against the Deacs were NC State, FSU, Maryland, Virginia Tech, and Georgia Tech, and only NC State (which played Duke and UNC twice) ended up in the top half of schedule difficulty. Of course, Wake meant an extra free win for all of these teams, so that's probably appropriate.

So with all of this information, we can adjust performance to see how the teams would have performed against an average schedule. The unadjusted performance looks like this:


Margin
Duke 16.64
North Carolina 10.28
Clemson 6.42
Virginia Tech 5.66
Florida State 4.00
Maryland 0.67
Boston College -0.50
Miami -2.38
Georgia Tech -3.06
Virginia -3.92
NC State -7.85
Wake Forest -25.97

Adjusted, we get a bit of movement - BC and Miami leapfrog Maryland, and Virginia jumps Georgia Tech and NC State:


Margin
Duke 17.46
North Carolina 12.63
Clemson 6.17
Virginia Tech 4.08
Florida State 3.55
Boston College 0.60
Miami 0.13
Maryland -0.52
Virginia -3.17
Georgia Tech -4.77
NC State -7.51
Wake Forest -26.94

Finally, based on the adjusted performance of the teams this season, here are the tourney odds. Duke comes out as a strong favorite (not quite as strong as last year, but still a heavy favorite). This is a good time for the following reminder - statistically, Duke was almost as strong in conference as last year's team; statistically, this year's UNC team was almost as strong in conference as last year's Maryland team. The profiles at the top of the conference are extremely similar this year to last year.


Quarters Semis Finals Win
2 Duke 100.00% 93.85% 82.33% 60.50%
1 North Carolina 100.00% 87.00% 65.19% 26.82%
4 Clemson 100.00% 69.48% 24.20% 5.96%
3 Florida State 100.00% 55.49% 8.84% 2.77%
6 Virginia Tech 77.47% 39.32% 6.40% 2.04%
5 Boston College 97.91% 30.50% 6.34% 0.90%
9 Miami 61.58% 9.20% 3.28% 0.45%
7 Maryland 71.00% 5.24% 1.93% 0.38%
8 Virginia 38.42% 3.80% 0.98% 0.09%
11 Georgia Tech 22.53% 5.19% 0.32% 0.04%
10 NC State 29.00% 0.91% 0.18% 0.02%
12 Wake Forest 2.09% 0.02% 0.00% 0.00%

A couple thoughts. First, the odds are about 75% that one of Duke or UNC will be playing on Sunday, and 50% that both will match up. Duke's numbers are better than UNC's for a couple of reasons - first, because Duke played better in conference, and second, because Clemson and Miami are better statistically than their records - Clemson's a 3-seed that ended up 4th, and Miami is a 7-seed that ended up 9th. Both present above-seed threats to UNC. Also, five teams have essentially the same (or better) chance of winning the whole thing as Wake does of beating BC - they were really, really bad this year.

Finally, this will almost certainly be different from whatever odds Pomeroy runs later this week, because this takes into consideration only ACC play, while his will factor in non-conference games. Duke will still end up as a favorite, but it will be lower - my bet is that we'll end up with about a 50% chance of winning it all, Carolina between 25-30%, and everyone else scattered at 7% or lower.

[MChambers]

Thanks for doing this. It tends to confirm what I suspected. Hope it is borne out by the results in the tournament.

[kong123]

So, Kenpom says that Duke had the 10th toughest conference schedule out of 12 teams and you found a way to prove him wrong with his own numbers?

[hurleyfor3]

How did you compute the initial home/road breakdowns for each team? By hand? I don't see a way to get this info on Pom's Web site.


The strength of schedule is derived from figuring out the collective offensive and defensive ratings of the 16 teams you played, with your own performance factored out (so Wake's schedule doesn't look harder because it stank, and Duke's easier because it dominated). I figured out both the offensive and defensive degree of difficulty for each team. The disparities may look small, but keep in mind that the teams averaged just shy of 1100 total possessions in ACC play this season, so a difference of 2.00 in margin is 22 points over the course of the season.

So, for example, the rating for the "home Virginia Tech" doesn't include its victory over us when you compute our SOS -- you use only VPI's seven non-Duke home conference games. Right?


O Marg
Miami 2.51
North Carolina 2.35
Boston College 1.09
Duke 0.82
Virginia 0.75
NC State 0.34
Clemson -0.25
Florida State -0.45
Wake Forest -0.97
Maryland -1.19
Virginia Tech -1.59
Georgia Tech -1.70

I generally suspect SOS is slightly negatively correlated within a conference, as Duke doesn't have to play Duke, and Wake doesn't get to play Wake. But as long as you adjusted for opponents' performance against yourself, I can't think of a reason to quibble (yet).


So, Kenpom says that Duke had the 10th toughest conference schedule out of 12 teams and you found a way to prove him wrong with his own numbers?

I think Pom's conference SOS numbers use the overall ratings of each conference opponent. I would guess Duke's rating here suffers because the rest of the ACC doesn't have a whole lot of good nonconference wins, whereas we do.

[JohnGalt]

So, Kenpom says that Duke had the 10th toughest conference schedule out of 12 teams and you found a way to prove him wrong with his own numbers?

10th of 12th is, perhaps, a result of not having to play themselves?

[kong123]

same could be said for UNC.

[pfrduke]

So, Kenpom says that Duke had the 10th toughest conference schedule out of 12 teams and you found a way to prove him wrong with his own numbers?

I'm not using his numbers, I'm using mine. They differ in three respects - first, I don't adjust for opponent; he does. That is, he uses an "adjusted" offensive and defensive efficiency that takes into account strength of schedule, I don't (because I'm not mathematically savvy enough to do it). Second, as I described in my initial post, I split the conference into 24 teams, rather than 12 - a home and road version of each team. So if you only play FSU in Tallahassee, for example, only FSU's performance as a home team is factored in to your strength of schedule. Third, I suspect (although am not certain) that his strength of schedule uses season long performance by the teams, including non-conference games, while mine uses in-conference performance only.

I'm sure my method is subject to criticism. Pomeroy's is, too - frankly, the fact that he has UNC with only the 6th toughest schedule in conference just seems wrong when, as you and I have both pointed out, they had to face Duke, FSU, and Clemson twice.

[pfrduke]

How did you compute the initial home/road breakdowns for each team? By hand? I don't see a way to get this info on Pom's Web site.

I keep track on my own throughout the season. It's my stat geek guilty pleasure. So I can break it down into home and away. The baseline method for calculating efficiency is the same. That being said, you could mine similar data from Pomeroy's site by pulling it from the team's Game Plan pages. There would be a fair amount of manual work involved, but the necessary information is there.



So, for example, the rating for the "home Virginia Tech" doesn't include its victory over us when you compute our SOS -- you use only VPI's seven non-Duke home conference games. Right?

Essentially, yes, although I do it cumulatively (that is, the opponent's performance in all 8 games (either home or road) go in to the mix, all 16 opponents' performances get added up, and then Duke's (for example) gets subtracted out). That's probably not a perfect way to do it - there should be some way to weigh the team's performance even in the games you play against them, but I'm not quite mathematically savvy enough to figure out how to do it.

[sandinmyshoes]

I'm not using his numbers, I'm using mine. They differ in three respects - first, I don't adjust for opponent; he does. That is, he uses an "adjusted" offensive and defensive efficiency that takes into account strength of schedule, I don't (because I'm not mathematically savvy enough to do it). Second, as I described in my initial post, I split the conference into 24 teams, rather than 12 - a home and road version of each team. So if you only play FSU in Tallahassee, for example, only FSU's performance as a home team is factored in to your strength of schedule. Third, I suspect (although am not certain) that his strength of schedule uses season long performance by the teams, including non-conference games, while mine uses in-conference performance only.

I'm sure my method is subject to criticism. Pomeroy's is, too - frankly, the fact that he has UNC with only the 6th toughest schedule in conference just seems wrong when, as you and I have both pointed out, they had to face Duke, FSU, and Clemson twice.

Thanks for all the info! As you say, most mathematical models are going to have weaknesses in this sort of thing. As noted, UNC didn't face FSU at FSU with their best player. On the otherhand, taking season's worth of games to project a tourney often fails to take into consideration how teams are "trending" right now, which I have to admit UNC is trending up. Never mind the good ol' human element that carried UVA to a title in 76.

But it's fun to have all these different angles to check out for curiosities sake.

[Kedsy]

Wow, thanks, this is so cool.

Interesting that the conference defenses we faced were the fourth worst. Obviously one reason for this is we don't face our own defense, but it still means that maybe our offense hasn't been tested so much.

[pfrduke]

Finally, this will almost certainly be different from whatever odds Pomeroy runs later this week, because this takes into consideration only ACC play, while his will factor in non-conference games. Duke will still end up as a favorite, but it will be lower - my bet is that we'll end up with about a 50% chance of winning it all, Carolina between 25-30%, and everyone else scattered at 7% or lower.

Pomeroy's are up on Basketball Prospectus, and as predicted, Duke is given a 54.5% chance of winning and Carolina a 30.5% chance of winning. As far as the rest of the conference shakes out, Maryland scores higher than BC and Miami in Pomeroy's odds, while Virginia checks in below Georgia Tech and NC State, but otherwise the order is the same.

[Reilly]

If I read the chart up above correctly:

pfr acc-only #'s give Duke a 60% of winning it all; UNC a 26% chance.
kenpom's #'s give Duke a 54% chance of winning it all; UNC a 31% chance.

Intuitively, just looking at the brackets, I like Duke's chances a bit better than UNC's chances, if I were to assign odds myself, but not to the tune of the disparity that either set of computer-generated numbers produces.

pfr, curious as to what your non-computer (but still analytic) sense is. That is, do you like Duke's chances better than UNC's? To the degree that the computers say?

[pfrduke]

If I read the chart up above correctly:

pfr acc-only #'s give Duke a 60% of winning it all; UNC a 26% chance.
kenpom's #'s give Duke a 54% chance of winning it all; UNC a 31% chance.

Intuitively, just looking at the brackets, I like Duke's chances a bit better than UNC's chances, if I were to assign odds myself, but not to the tune of the disparity that either set of computer-generated numbers produces.

pfr, curious as to what your non-computer (but still analytic) sense is. That is, do you like Duke's chances better than UNC's? To the degree that the computers say?

I think I end up in the same boat as you do - I like Duke's chances better than UNC's, both because I do think Duke is better at the end of the day and because I like our road better than Carolina's - I think they'll likely be playing a better team than we will at every round of the tournament. There's also something to be said for the mindset difference, given Carolina's disregard for the ACCT as compared to K's burning desire to win every tournament he's in - that counts for something in the earlier rounds, although I'm not sure it would be any factor in a Duke-UNC final. I'm not sure I'm quite as gungho on our chances as my numbers say, but mostly because I don't think we're as heavy a favorite in a Duke-UNC matchup as the numbers would predict. But Pomeroy's seem reasonable - calling the ACC championship a slightly better than 50/50 proposition for Duke seems about right, given that I do think we're very likely to make the finals, Carolina is less likely than us to make the finals, and we're more likely than not to beat UNC if we play each other.

I will say that part of my confidence comes from a firm belief that Kyle Singler won't keep playing this poorly on offense - that he's having a blip, and that he'll regress to his mean (regression in this case resulting in an improvement in play). If Kyle continues as he's going, I think our odds would drop below 50%, and there's a more meaningful chance that, for example, a hungry/desperate Virginia Tech team beats us in the semis.

[WakeDevil]

What are the odds that people will learn the difference between effectiveness and efficiency?

[ikiru36]

This analysis is awesome and probably provides as close to an accurate depiction of team strength based on an entire ACC unbalanced season's performance as is possible statistically. I'd also love for it to be proven accurate as a predictive device! :0)

Nevertheless, some teams are clearly playing much better ball now (UNC being an obviously prime example) than they were earlier in the year. Also, I don't think Duke has been quite as dominant in the last month as they were earlier. I would want recent performance weighted somehow before feeling that the model was likely to predict the tournament results with ideal accuracy.

Re: UNC, they seem particularly difficult to predict as their improved play of late has still included a number of so-so games in which they just squeaked by relatively lesser opponents (Clem, FSU and BC, all 2 pt. wins during February). Duke, by comparison, has been far more dominant in their winning efforts throughout the ACC season. Also, the recent Bullock injury, while not dramatically affecting their primary rotation, further reduces their backcourt depth which could be a negative during a game-a-day tournament.

In Duke's case, there's clearly been some improvement from many on the team over the course of the season. If that were maintained (Seth Curry's improvement in conjunction with Mason's consistent rebounding and flashes of quality play from Ryan and Miles) and Kyle were to simply recover his shooting stroke, Duke immediately becomes borderline-Elite again, even without KI. That's without even mentioning what Andre Dawkins could add if able to maximize his strengths and play closer to his seeming capabilities. Still that's a lot of "ifs" and that's why they play the games.

In any event, thanks again for sharing all the hard work you've done!

Go Duke!!!!!!!!!!!!! Go Blue Devils!!!!!!!!!!!!!!!!!!! GTHCGTH!!!!!!!!!!!!!!!!!!!!

[DukieinSoCal]

This analysis is awesome and probably provides as close to an accurate depiction of team strength based on an entire ACC unbalanced season's performance as is possible statistically. I'd also love for it to be proven accurate as a predictive device! :0)

Nevertheless, some teams are clearly playing much better ball now (UNC being an obviously prime example) than they were earlier in the year. Also, I don't think Duke has been quite as dominant in the last month as they were earlier. I would want recent performance weighted somehow before feeling that the model was likely to predict the tournament results with ideal accuracy.

Re: UNC, they seem particularly difficult to predict as their improved play of late has still included a number of so-so games in which they just squeaked by relatively lesser opponents (Clem, FSU and BC, all 2 pt. wins during February). Duke, by comparison, has been far more dominant in their winning efforts throughout the ACC season. Also, the recent Bullock injury, while not dramatically affecting their primary rotation, further reduces their backcourt depth which could be a negative during a game-a-day tournament.

In Duke's case, there's clearly been some improvement from many on the team over the course of the season. If that were maintained (Seth Curry's improvement in conjunction with Mason's consistent rebounding and flashes of quality play from Ryan and Miles) and Kyle were to simply recover his shooting stroke, Duke immediately becomes borderline-Elite again, even without KI. That's without even mentioning what Andre Dawkins could add if able to maximize his strengths and play closer to his seeming capabilities. Still that's a lot of "ifs" and that's why they play the games.

In any event, thanks again for sharing all the hard work you've done!

Go Duke!!!!!!!!!!!!! Go Blue Devils!!!!!!!!!!!!!!!!!!! GTHCGTH!!!!!!!!!!!!!!!!!!!!

Good points. And FSU likely would have beaten UNC with a healthy Singleton, like we had to face. There's no way to factor in important injuries with these stats. You could probably even make a stronger case for Duke.

And our superior numbers on the road compared to UNC is likely due to the experience on our roster compared to relative youth of UNC. I wouldn't be surprised to see UNC struggle away from home, ie. in the ACC and NCCAT.

[rasputin]

What are the odds that people will learn the difference between effectiveness and efficiency?

The same as the odds that people will learn the difference between irony and coincidence.

[kong123]

Good points. And FSU likely would have beaten UNC with a healthy Singleton, like we had to face. There's no way to factor in important injuries with these stats. You could probably even make a stronger case for Duke.

And our superior numbers on the road compared to UNC is likely due to the experience on our roster compared to relative youth of UNC. I wouldn't be surprised to see UNC struggle away from home, ie. in the ACC and NCCAT.


UNC lost 2 ACC games away from home this year and Duke lost 3 ACC games away from home.

[rsvman]

UNC lost 2 ACC games away from home this year and Duke lost 3 ACC games away from home.

Yes, but they required a last-second shot to win against a Florida State team that was without its best player. The argument here is that they would likely have lost they game had Singleton not been out with an injury. Obviously, that's not a certainty, and anything could've happened.

[ns7]

UNC lost 2 ACC games away from home this year and Duke lost 3 ACC games away from home.

Duke's efficiency margin on the road was significantly better than UNC's margin. Please read the first post.


Road Team Off Def Margin
Duke 109.46 96.95 12.51
North Carolina 104.67 99.81 4.86

[El_Diablo]

UNC lost 2 ACC games away from home this year and Duke lost 3 ACC games away from home.

I think you missed the point. UNC had a slimmer efficiency margin on the road. The obvious reasons: they had lots of close wins over inferior opponents, and they lost their two ACC games by more total points than Duke's three ACC losses.

So UNC had a weaker overall road margin...no big deal. It's not an indictment of your program, it's just the math. And some of us actually appreciate the work that went into it.

[gumbomoop]

UNC lost 2 ACC games away from home this year and Duke lost 3 ACC games away from home.

This is an accurate, but somewhere between slightly and significantly misleading, statement. Would you agree - or deny - that the unbalanced schedule always makes simple won-loss comparisons misleading?

IMO, UNC was spared 3 tough away contests: no visit to Md or VaTech, no Singleton at FSU.

Duke avoided 1 additional tough away contest: at Clemson.

It does strike me that the purpose of your particular comment here is to imply that the OP's analysis is neither interesting nor meaningful. But maybe I've misunderstood you, and have inferred a put-down where you intended none.

Having said this, I hasten to add that the Heels played a fine game last Sat eve. I haven't visited IC in quite some time, but assume the early-season angry debate between Drew supporters and detractors has subsided. Nor, I assume, do folks over there pine for either Graves or the Wears. Were I a Heel fan, I'd be feeling confident right now, whistling past the graveyard, perhaps, about close wins, but thinking positively that even unimpressive wins are wins. I'd be saying, "Our guys know how to win the close ones." I'd also be hoping - secretly and with just a small tinge of nervousness - that Kyrie will not reappear this season.

[4decadedukie]

This is a superb, painstaking analysis, for which I am extremely greatful.

With this sincerely said, I have a long-standing problem with such wholly quantitative (completely non-qualitative) evaluations re Duke's strength-of-schedule. Whether at home or on the road, essentially EVERY team the Blue Devils face will play with extra effort, focus and special ferocity, year after year. I believe this is due to the fact that Duke is a -- perhaps "the" -- perennial paradigm for top-tier Division I excellence. Therefore, defeating Duke "makes" any team's season, even if the rest of their campaign is a disaster. We see this in SO MANY games every year, for example our recent loss to VPI and our recent victory against Clemson.

If this foregoing premise is correct, what is a normally mediocre team for any legitimate quantitative rating, is likely to play like an excellent team when it faces Duke. Obviously, this consequentially means that mediocre opponents in the numerical analysis -- based on their aggregate, season-long performance -- should be assessed as much more demanding contestants for Duke.

In essence, our strength-of-schedule should NOT be based on how our opponents generally perform, but rather how they perform against the Blue Devils.

[kong123]

Duke's efficiency margin on the road was significantly better than UNC's margin. Please read the first post.


Road Team Off Def Margin
Duke 109.46 96.95 12.51
North Carolina 104.67 99.81 4.86

thats fine, UNC's conference record was better than Duke's. That is a better indicator to me :)

[nocilla]

thats fine, UNC's conference record was better than Duke's. That is a better indicator to me :)

The Cleveland Cavaliers had the best record in the NBA last year.

I don't mean to discredit the regular season. It is a nice achievement. Congratulations to UNC for winning the regular season. You earned a #1 seed for the Conference Championship.

[ns7]

thats fine, UNC's conference record was better than Duke's. That is a better indicator to me :)

Then I have no idea why you're reading a thread about advanced metrics unless you're trolling.

Here's one for you: Green Bay was the #6 seed in the NFC but when you looked at advanced metrics, they were the best team in the NFC entering the playoffs.

[dukeballboy88]

To me, and ive said this for awhile, when the acc added more teams and everyone didnt play each other twice, it ruined the acc regular season title. I dont know how you can crown a champ when you dont play everyone at home and away.

The conference tourney has to mean more these days. The NCAA should implement a rule that says you cant get a #1 seed unless you win your conference tourney or something. From what Im reading, this ACC tourney is going to give the winner a #1 seed if either Duke or UNC win it. I guess lil roy cant claim to take this weekend off this year!

My question about sos is, if Kansas St and Marquette, 2 teams Duke beat, win both of their conference tourneys will that help Duke's sos or rpi and getting a #1 seed?

[flyingdutchdevil]

Good job to the OP for the heavily quantitative analysis. Quite interesting.

That said, there is an argument going on between pro-UNCers (ie Kong) and everyone else. Hate to say it, but I agree with Kong. I may be completely off base, but I feel like a lot of people are using the OP's analysis to say that even though UNC won the reg. season ACC, Duke 'deserved' to win the reg. season ACC because of a more difficult SOS. Really? Kong is right - UNC won the ACC fair and square. That does not mean that UNC is the better or more talent team. It means that they pulled out the most wins against a similar set of opponents. They have a better record and so they deserve the credit.

That said, I hope (and know) that Duke will absolutely destroy their opponents during the ACC tournament. If that means facing UNC during the ACC final, so be it. I'm looking forward to the challenge.

[mus074]

Awesome, awesome work. Thanks for sharing it. I enjoyed reading about your process at least as much as the results of the analysis. It is worth remembering that in the end, we are taking about statistical probabilities. If each match up were a best of seven series, the probabilities would be a much better indicator of who will win, and we could only prove the accuracy of the probabilities if we could somehow get the teams to play the same tournament over and over and over again to compare the distribution of results to the forecasted probabilities.



I'm not using his numbers, I'm using mine. They differ in three respects - first, I don't adjust for opponent; he does. That is, he uses an "adjusted" offensive and defensive efficiency that takes into account strength of schedule, I don't (because I'm not mathematically savvy enough to do it). Second, as I described in my initial post, I split the conference into 24 teams, rather than 12 - a home and road version of each team. So if you only play FSU in Tallahassee, for example, only FSU's performance as a home team is factored in to your strength of schedule. Third, I suspect (although am not certain) that his strength of schedule uses season long performance by the teams, including non-conference games, while mine uses in-conference performance only.

I'm sure my method is subject to criticism. Pomeroy's is, too - frankly, the fact that he has UNC with only the 6th toughest schedule in conference just seems wrong when, as you and I have both pointed out, they had to face Duke, FSU, and Clemson twice.

Just for the sake of further comparison, Pomeroy adjusts for home court advantage by giving a small adjustment (I think maybe 4%) to the home team and the same amount taken from the away team. I have a fundamental problem with this format. It works well when looking at all teams in the aggregate and for seeking to compare apples to apples. However, I would love to see him use all of his raw data and derive two different factors for each team.

One would be how far from the projected efficiencies (not taking into account his home/road adjustment) each team is on the road and at home to see how much of an individualized factor it is for each team. I think your idea of splitting teams into two alter egos captures this concept much better. This would be very helpful in predicting future performance, as some teams (like UK) have different "road" and "home" factors than other teams.

The second would be to compare how teams fare against the predicted adjusted efficiencies based upon the level of competition. The adjusted efficiency seeks to take this into account, but I would guarantee some teams are more influenced by the opponent's ability than others, but the pythag theory gives equal "gravity," if you will, to all the teams relative to their performance. Looking for a statistical correlation of opponent level to distance from the predicted value would tease out what I think of as the team's "will." Do they trounce weak teams and play mediocre against better ones? Do they only show up against great teams and then sleep walk through lesser competition? This would also be valuable predictive information come tourney time, I think.

Thanks for indulging my inner geek. Your work is awesome and I thank you again for sharing it with us.

[dukeballboy88]

By the way, awesome work on the analysis, thanks for that!

[kong123]

Good job to the OP for the heavily quantitative analysis. Quite interesting.

That said, there is an argument going on between pro-UNCers (ie Kong) and everyone else. Hate to say it, but I agree with Kong. I may be completely off base, but I feel like a lot of people are using the OP's analysis to say that even though UNC won the reg. season ACC, Duke 'deserved' to win the reg. season ACC because of a more difficult SOS. Really? Kong is right - UNC won the ACC fair and square. That does not mean that UNC is the better or more talent team. It means that they pulled out the most wins against a similar set of opponents. They have a better record and so they deserve the credit.

That said, I hope (and know) that Duke will absolutely destroy their opponents during the ACC tournament. If that means facing UNC during the ACC final, so be it. I'm looking forward to the challenge.

I understand that the uneven schedule does create a debate over the regular season SOS and even the regular season champion. I understand that the numbers provided in this graph tell a different story than what the actual outcome was. In the end, you guys think the tournament champion trumps the regular season championship, but in another thread, many have pointed out that they think UNC has a tougher road to the final game than Duke does. If it were the best of 3 or 5 games, then the tournament would be a better indication of a true championship, but since the teams are seeded due to their conference record, not statistics like the ones provided in this thread, then can't someone make the same argument against the tournament? Isn't the longer ACC regular season a better indicator to the strength of a team than a 3 day tournament where the seeding of the teams doesn't reflect the strength of a team, therefore the tournament is even less balanced and fair than the regular season?

[mus074]

Good job to the OP for the heavily quantitative analysis. Quite interesting.

That said, there is an argument going on between pro-UNCers (ie Kong) and everyone else. Hate to say it, but I agree with Kong. I may be completely off base, but I feel like a lot of people are using the OP's analysis to say that even though UNC won the reg. season ACC, Duke 'deserved' to win the reg. season ACC because of a more difficult SOS. Really? Kong is right - UNC won the ACC fair and square. That does not mean that UNC is the better or more talent team. It means that they pulled out the most wins against a similar set of opponents. They have a better record and so they deserve the credit.

That said, I hope (and know) that Duke will absolutely destroy their opponents during the ACC tournament. If that means facing UNC during the ACC final, so be it. I'm looking forward to the challenge.

I think you may be misstating the value or meaning of pfr's awesome analysis. It looks at the approximately 1100 possessions per team or 13,200 total data points to see how well each team did on each possession. Pure win/loss records gives you a separate and different analysis of only 192 data points. They tell different stories, but don't trump the other. A better per possession efficiency doesn't mean you deserved to win more games. Nor does winning more games mean you will necessarily win any one future game.

[mus074]

Isn't the longer ACC regular season a better indicator to the strength of a team than a 3 day tournament where the seeding of the teams doesn't reflect the strength of a team, therefore the tournament is even less balanced and fair than the regular season?

In the end, the team that wins 6 in a row in single elimination wins the crown in college basketball. In football, its the season that matters. Not trying to say one is better - that's just how its done.

[kong123]

They tell different stories, but don't trump the other. A better per possession efficiency doesn't mean you deserved to win more games. Nor does winning more games mean you will necessarily win any one future game.

I completely agree with this.

in the end, you have to play the opponent in front of you. after that, you are judged by whether or not you won the game. the other statistics provided, like the ones in this thread, can provide a different perspective, but ultimately, they are only for entertainment and can be used to confirm the results or to spin the results in a different direction. bottom line, you still have to win the games to make it count.

[davekay1971]

same could be said for UNC.

There's a very simple explanation: Duke's strength of schedule was hurt by having to play UNC twice, while UNC's was helped by having the opportunity to play Duke twice. UNC's status as a basketball school has been bouyed up by their proximity to Duke for the last 25 years...why should this year be any different?

(The above written with my tongue planted firmly in cheek, I assure you)...

Joking aside, the OP, like KenPom's analysis technique, is a marvellous way to get past the more simple win-loss record to predict future events in sports. The limitation, of course, is that a single game is, to some degree, unpredictable, which is why college basketball's post-season single game formats have a nasty way of refusing to follow predictions (KenPom's well documented success in predicting NCAAT contenders being a notable exception). To the point of this discussion, Kong may consider the OP's analysis to be data spin, but it's actually a very nice statistical look at the overall ACC conference performance of each team. It MAY be helpful in predicting outcomes of the ACCT...as long as groups of 18-22 year olds perform, during the individual conference games, to the level they performed over the course of the season.

With regards to which is a better measure of who's the best team in the conference - regular season record vs conference tournament, I would submit that both are flawed. If the conference season was balanced, I would say it was the better measure. With the conference season being markedly unbalanced, conference season record becomes a deeply flawed way to determine who was the best team in conference. Thus the decision in the days of the old Southern Conference to make the tournament winner the conference champion. During the days of the 8 team ACC, the regular season could have (perhaps should have) fairly determined the conference champion. Now that we're back to unbalanced schedules, however, the tournament can be argued to be a more equitable way to determine a champion.

If, however, we think that comparing regular season records of teams that play different schedules is the most equitable way to determine a champion, perhaps the NCAA should use the regular season performance to determine the national champion? A nice computerized amalgamation of national polls and computer polls would leave everyone feeling satisfied, I'm sure...

[DevilBen02]

I may be completely off base, but I feel like a lot of people are using the OP's analysis to say that even though UNC won the reg. season ACC, Duke 'deserved' to win the reg. season ACC because of a more difficult SOS. Really? Kong is right - UNC won the ACC fair and square. That does not mean that UNC is the better or more talent team. It means that they pulled out the most wins against a similar set of opponents. They have a better record and so they deserve the credit.

You are correct that the information presented here should not be used to argue that Duke "deserved" to win the regular season. With regard to the regular season, playing with these numbers is merely an academic exercise because the games have been played and the outcomes are known. No matter how you look at the numbers, UNC got the wins and should be congratulated for earning the top seed.

I believe that the point of the numbers, however, is that wins and losses alone don't tell the whole story of what a team has done and what they may be capable of doing in future games. In that regard, although we can't really argue that Duke should be considered the regular season champ, the numbers provide a reasonable argument that Duke is in fact the better team despite the conference record and is more likely to be successful going forward.

[kong123]

You are correct that the information presented here should not be used to argue that Duke "deserved" to win the regular season. With regard to the regular season, playing with these numbers is merely an academic exercise because the games have been played and the outcomes are known. No matter how you look at the numbers, UNC got the wins and should be congratulated for earning the top seed.

I believe that the point of the numbers, however, is that wins and losses alone don't tell the whole story of what a team has done and what they may be capable of doing in future games. In that regard, although we can't really argue that Duke should be considered the regular season champ, the numbers provide a reasonable argument that Duke is in fact the better team despite the conference record and is more likely to be successful going forward.

agreed. I also feel that Duke is the more experienced and therefore the more consistent of the two teams. This is reflected in the data presented in this thread.

[flyingdutchdevil]

You are correct that the information presented here should not be used to argue that Duke "deserved" to win the regular season. With regard to the regular season, playing with these numbers is merely an academic exercise because the games have been played and the outcomes are known. No matter how you look at the numbers, UNC got the wins and should be congratulated for earning the top seed.

I believe that the point of the numbers, however, is that wins and losses alone don't tell the whole story of what a team has done and what they may be capable of doing in future games. In that regard, although we can't really argue that Duke should be considered the regular season champ, the numbers provide a reasonable argument that Duke is in fact the better team despite the conference record and is more likely to be successful going forward.

This is a great post. I agree with basically everything that you have said. However, stats don't tell the whole story. It looks like standard deviation has not been considered a factor. On either a game or a single possession basis, I'd be surprised if Duke has a lower SD than UNC. That is relevant because that is a prime statistic for consistency. While Duke may have overall better efficiency in the long haul, the fact that it is more inconsistent (assumption based on eyeballing numbers, not actually doing the analysis) with a higher SD isn't better than having lower efficiency numbers with a smaller SD (ie UNC). For instance - and this is incredibly simple and not based on any data - but winning 5 games by 5 points is less efficient than winning 4 games by 12 and losing 1 by 1, but the former has a lower SD and higher consistency.

[mus074]

This is a great post. I agree with basically everything that you have said. However, stats don't tell the whole story. It looks like standard deviation has not been considered a factor. On either a game or a single possession basis, I'd be surprised if Duke has a lower SD than UNC. That is relevant because that is a prime statistic for consistency. While Duke may have overall better efficiency in the long haul, the fact that it is more inconsistent (assumption based on eyeballing numbers, not actually doing the analysis) with a higher SD isn't better than having lower efficiency numbers with a smaller SD (ie UNC). For instance - and this is incredibly simple and not based on any data - but winning 5 games by 5 points is less efficient than winning 4 games by 12 and losing 1 by 1, but the former has a lower SD and higher consistency.

I also would love to see the SD on the teams' conference season performances. I would think at least that Duke's offensive performance is less consistent for the simple fact that Duke relied much more heavily in conference play on 3's than did UNC. Duke got 29.5% of its point in conference games from 3's (6th of 12), while UNC got only 18.9% of its points from 3's (11th) and 61.0% of its points from 2's (1st). I am assuming that UNC's distribution of effective shooting percentages was much tighter than Duke's, particularly since the eFG% gives a 50% premium to the 3-point variety.

[pfrduke]

I also would love to see the SD on the teams' conference season performances. I would think at least that Duke's offensive performance is less consistent for the simple fact that Duke relied much more heavily in conference play on 3's than did UNC. Duke got 29.5% of its point in conference games from 3's (6th of 12), while UNC got only 18.9% of its points from 3's (11th) and 61.0% of its points from 2's (1st). I am assuming that UNC's distribution of effective shooting percentages was much tighter than Duke's, particularly since the eFG% gives a 50% premium to the 3-point variety.

Ask and ye shall receive.

Duke's standard deviation for offensive efficiency was 13.5, with performances ranging from a low of 88.2 to a high of 127.6. 7 performances were between 100 and 120, with 5 below and 4 above. Our eFG standard deviation was 6.1% - we were never lower than 40, and only once higher than 60.

Carolina was actually less consistent, in part because of a higher high (139.5) and a lower low (77.4). They did end up with 8 performances between 100 and 120 (including 5 of the last 6), with 6 below and 2 above. Their eFG also varied more - a standard deviation of 9% with 4 games below 40 and 2 above 60.

[mus074]

Ask and ye shall receive.

Duke's standard deviation for offensive efficiency was 13.5, with performances ranging from a low of 88.2 to a high of 127.6. 7 performances were between 100 and 120, with 5 below and 4 above. Our eFG standard deviation was 6.1% - we were never lower than 40, and only once higher than 60.

Carolina was actually less consistent, in part because of a higher high (139.5) and a lower low (77.4). They did end up with 8 performances between 100 and 120 (including 5 of the last 6), with 6 below and 2 above. Their eFG also varied more - a standard deviation of 9% with 4 games below 40 and 2 above 60.

I am not disappointed to be wrong.

To ask the other question - what about the consistency/SD of defense? - as I am sure our welcomed guest from the paler shade of blue will also want to know.

Thanks!!

[flyingdutchdevil]

Ask and ye shall receive.

Duke's standard deviation for offensive efficiency was 13.5, with performances ranging from a low of 88.2 to a high of 127.6. 7 performances were between 100 and 120, with 5 below and 4 above. Our eFG standard deviation was 6.1% - we were never lower than 40, and only once higher than 60.

Carolina was actually less consistent, in part because of a higher high (139.5) and a lower low (77.4). They did end up with 8 performances between 100 and 120 (including 5 of the last 6), with 6 below and 2 above. Their eFG also varied more - a standard deviation of 9% with 4 games below 40 and 2 above 60.

This is fantastic. Thanks a lot PFR - I'm actually happily surprised. I would have lost a ton of cash if I had on the SD - thank god I didn't.

So, I stand corrected - Duke is not only more efficient but also more consistent. Nice.

[DevilWearsPrada]

Its almost Game time for the ACC tourney!

Which team is a better matchup for Unc (UVa or Miami)?

And then Are we pulling for NCState or Maryland today, for Duke matchup on Friday?

I am thinking about going to the games today. I know the tickets will be cheap and in abundance today! I would really like to see Maryland and State game!

Almost, Game time! NOON

[pfrduke]

I am not disappointed to be wrong.

To ask the other question - what about the consistency/SD of defense? - as I am sure our welcomed guest from the paler shade of blue will also want to know.

Thanks!!

Carolina had a more consistent defense - their SD was 8.8, while ours was 12.8. We had very spread defensive performances - 7 below 90, but 5 above 100. Carolina was slightly less spread - 6 below 90, 4 above 100, and 6 in between.

[Kedsy]

Carolina had a more consistent defense - their SD was 8.8, while ours was 12.8. We had very spread defensive performances - 7 below 90, but 5 above 100. Carolina was slightly less spread - 6 below 90, 4 above 100, and 6 in between.

This would help explain why Pomeroy thinks we have the #2 defense in the nation but several posters have lamented that our defense has been spotty lately.

[flyingdutchdevil]

This would help explain why Pomeroy thinks we have the #2 defense in the nation but several posters have lamented that our defense has been spotty lately.

Standard Deviation is a beautiful - and completely underused - tool in sports analytics.