Tuesday, January 22, 2008

ACC Look-Ahead: SDPI

One of my favorite set of posts from last offseason was the conference recap using SDPI. SDPI is a statistic I borrowed from Eddie Epstein that he used in his book, Dominance, to rank pro football's all-time greatest teams. SDPI stands for Standard Deviation Power Index and looks at how teams performed relative to the league average (or conference average in this case) and standard deviation in terms of points scored and allowed. The more standard deviations a team is above the mean, the better they are, and vice-versa. Here is the link to last year's ACC post. As you can see, SDPI was a useful tool in predicting some of the rise and fall among the ACC's teams. In the interest of providing an even better offseason analysis, I will now be conducting another SDPI, this time for yardage. It is calculated in the same manner as the SDPI for points, but will obviously be measured against the conference mean and standard deviation for yards. Think of it this way: Points are the end result and yards are the means to that end. Thus, looking at both sets of data, we can get an even better idea about which teams are likely to improve or regress in 2008.

If you want the meat of the article, skip this next paragraph as it just gives an example of how the SDPI is calculated. The mean points scored and allowed for all ACC teams in conference play (championship game not included) was 187.75 points. The standard deviation for points scored was 39.26. The standard deviation for points allowed was 43.06. Maryland scored 194 points in ACC play and allowed 180. Their offensive SDPI was 0.16 = ([194-187.75]/39.26). Their defensive SDPI was 0.18 = ([187.75-180]/43.06). Their total SDPI for points (SDPIP) was 0.34 which ranked 7th in the conference. The mean yardage for and against for all ACC teams in conference play (championship game not included) was 2762.17 yards. The standard deviation for yardage for was 338.33. The standard deviation for yards allowed was 351.69. Maryland gained 2780 yards in conference play and allowed 3081. Their offensive SDPI was 0.05 = ([2780-2762.17]/338.33). Their defensive SDPI was -0.91 = ([2762.17-3081]/351.69). Their total SDPI for yards (SDPIY) was -0.85 (difference due to rounding) which ranked 9th in the conference.

To refresh your memory, here are the 2007 ACC Standing.

Now here are the 2007 SDPI standings with conference rank in parentheses.

Both versions of SDPI correspond pretty well to the actual standings. Both versions see Clemson as the best team in the Atlantic Division, but as has become a common refrain around the upstate, Bowden just 'can't win the big one' (or 'un as it were). One stat that really jumps off the page is how dominant Virginia Tech looked in regards to points and scoring margin versus yardage. The Hokies outscored their ACC opponents by 135 points in 8 games (almost 17 per game), but 'only' outgained league foes by about 80 yards per game. One reason for this large disparity is the fact that the Hokies scored 4 non-offensive touchdowns in ACC play (2 interceptions, 1 punt return, and 1 kickoff return), including 3 in the game against Clemson, allowing them score 41 points and win by 18 despite gaining only 219 yards. Another facet of that dichotomy is that the Hokies outstanding defense (2nd in SDPI yards and first in SDPI points) consistently gave the offense outstanding field position either through turnovers (+15 in ACC play) or forcing 3 and outs. The second team that shifts a little when we contrast points and yards is Wake Forest. Based on points scored and allowed, the Deacons finished about where they should have, but in regards to yardage they finished better than expected. Wake can also thank non-offensive touchdowns for their good fortune. The Deacons returned one fumble, one kickoff, and 5 interceptions for scores in their 8 ACC games. The final team with a large disparity between points and yards in Georgia Tech. Using the SDPIP, the Jackets finished a little below the middle of the pack (8th place) as they were outscored by 13 points in ACC play. However, when we look at yardage, they shoot into the top 4. Unlike the Hokies and Deacons, the Jackets only managed a single non-offensive touchdown in ACC play and were -8 in turnover margin.

Best Offense: Virginia Tech 1.71 (SDPIP), Boston College 2.06 (SDPIY)
The Hokies scored the most point and the Eagles gained the most yards. Virginia Tech's proclivity at scoring on defense and special teams allowed them to score more points despite gaining about 78 fewer yards per game than the Matt Ryan led Eagles.

Worst Offense: Duke -1.45 (SDPIP) and -2.14 (SDPIY)
No controversy here as Duke was simply terrible at moving the ball. Good luck Mr. Cutcliffe, you have your work cut out for you.

Best Defense: Virginia Tech 1.57 (SDPIP), Clemson 1.86 (SDPIY)
In points allowed per game the Tigers were second and in yards allowed per game the Hokies were second. Either way, these two were the cream of the defensive crop in the ACC. I'd be inclined to give the Tigers the edge as 4 touchdowns were scored against their special teams or offense versus 1 for Virginia Tech.

Worst Defense: Duke -1.79 (SDPIP), NC State -1.39 (SDPIY)
Again no surprise to see Duke at the bottom. It does have to be a little disturbing for Wolfpack fans to see they allowed the most yards in conference play (over 406 per game). To be fair, that statistic is bolstered by the 608 yards Clemson put up against them.

Hardest Schedule (based on cumulative SDPI of opponents): Duke 4.26 (SDPIP) and 3.91 (SDPIY)
The Devils played in the weaker division, but unlike their division brethren, did not have Duke on their schedule.

Easiest Schedule: Virginia -4.78 (SDPIP) and -5.80 (SDPIY)
The Cavs played in the easier division, and in their games against Atlantic teams, they avoided the clear cut powers, Clemson and Boston College.

Looking ahead to next season, the prohibitive favorite should be...

Atlantic: Clemson
If Clemson fails once again in their quest to play in the ACC Championship Game, Mr. Bowden may be in serious trouble. The past 3 seasons, the Tigers have finished within one game of the Atlantic Division lead each year, but have been unable to see the deal. If Shakespeare had any inklings of writing athletic tragedies, he could do a lot worse than model the Tigers' ACC sojourn. In the span, the Tigers have lost 10 ACC games. 7 have been decided 6 points or fewer, and in 3 games, the margin has been a single point. Clemson brings back a senior starting quarterback, their top 2 running backs, every player who caught a pass save La'Donte Harris (only 12 catches), and a host of talent on defense. They do face 3 touch road games within the division (Florida State, Boston College, and Wake Forest), but with the departure of Matt Ryan, this is clearly Clemson's race to lose.

Coastal: Virginia Tech
Though not as dominant as their point differential would indicate, the Hokies have to be the favorites to come out of the Coastal Division. They should be a much weaker pole leader than Clemson though. For starters, the Hokies lose their top 4 pass-catchers and the defensive unit loses stalwarts Xavier Adibi, Vince Hall, Chris Ellis, and DJ Parker, as well as any underclassmen who decide to leave early.

The team(s) that will improve are...

North Carolina and Georgia Tech
In the second season of the Butch Davis era, the Tar Heels should certainly get to bowl eligibility, and I wouldn't be too surprised if they hang around in the conference race. Last season, the Heels were involved in 8 one-score games. They won only 3 of those contests. Some improvement in both the luck department and from quarterback TJ Yates could mean big things for the Heels in 2008. Jealous fans of the Blue Devils and Wolfpack should not get too worried though. As the Butch Davis era approaches its zenith in 2010, some big-money school will come calling and despite protests to the contrary, Davis will be gone faster than a bottle of Jack in Phil Ford's refrigerator. Over in Atlanta, Paul Johnson is the right man for the job. In my opinion, Johnson is the best coach in the NCAA. He probably won't win an ACC Championship in his first season, but the indicators are there for some improvement in the Jacket's won/loss record. If the defense can remain in the good to steady range, the offensive improvement will put the Jackets in the Orange Bowl by January of 2012. As for other teams that may improve, I expect that come July we will be hearing a lot about how Miami and Florida State are about to reclaim their place at the table with college football's elite. Consider me skeptical until it happens. Especially Miami. They were simply atrocious in 2007. The offense was and has been bad for sometime now, but the defense also slipped last season. There are no positive indicators for a Canes' revival. Certainly, Miami could get to bowl-eligibility, but anything more than a 7-win regular season would be shocking. As for the Noles, well a second-place finish in the Atlantic would certainly not be out of the question, but that is more an indication of the relative parity (suckiness) of the ACC than any praise that should be heaped on the elder Bowden's boys.

The team(s) that will decline are...

Boston College, Wake Forest, and Virginia
The Eagles bid adieu to their senior quarterback, Matt Ryan, two of their better receivers (Andre Callender and Kevin Challenger), and the best players on their turnover happy defense (Jamie Silva, Jolonn Dunbar, DeJuan Tribble, and Nick Larkin). The Eagles' shot at the ACC was last season. Now the rebuilding must begin. My alma mater seems to owe the piper a healthy check after their good fortune the past 2 seasons. Although they return most of both starting lineups, the loss of both Kenny Moore and Kevin Marion will hurt the passing and return games. The extreme turnover margins (+13 in 2006 and +9 in 2007) and non-offensive touchdowns appear to be unsustainable, so don't be surprised if the Deacons slip in the standings. And finally we have Virginia, patron saint of winning ugly. While Wake did it first and better (in 2006), the Cavs seemed to have a rabbit's foot with them at all times. Take away the 48-point sloshing of Miami, and the Cavs scored 3 more points than they allowed in ACC play. Game-changing defensive end Chris Long is gone so the onus will be on the offense if the Cavs are to compete for anything more than a trip to Charlotte in 2008.

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