## Monday, March 02, 2009

### Big 12 2008 SDPI

One of my favorite set of posts from the past two offseasons has been the SDPI recap/early preview. Don't know what SDPI is? It stands for Standard Deviation Power Index and is a tool Eddie Epstein used in his book Dominance to rate pro football's best teams. The basic idea is to look at how far above or below average (by standard deviations) a specific team is relative to their conference brethren. Since each team plays the same number of conference games, it can give us a good idea about who the best team was within the conference. However, it cannot tell us which conference is better. But the purpose of these posts is not to determine which conference is superior, but rather project ahead which teams in a conference will be contenders or also rans in the upcoming season. In the first post on SDPI two years ago, I calculated SDPI based on points scored and allowed within conference play. Last season I used points scored and allowed as well as yards gained and allowed. This season, I'm sticking with yards only. The yardage version of SDPI has a better correlation with future performance than points, and including both last season made the post seem (at least to me) quite muddled. Of course, this is by no means, the end all be all rating system, but it can give us an idea of which teams will improve and decline in 2009. We've already looked at the ACC, Big East, and Big 10 so now we'll take a look at the Big 12.

If you want the meat of the article, skip this next paragraph as it just gives an example of how SDPI is calculated. The mean yardage for and against for all Big 12 teams in conference play (championship game excluded) was 3450.47 yards. The standard deviation for yards gained was 604.40. The standard deviation for yards allowed was 448.37. Kansas gained 3283 yards in conference play and allowed 3577 Their offensive SDPI was -0.28 = ([3283-3450.47]/604.40). Their defensive SDPI was -0.28 = ([3450.47-3577]/448.37). Their total SDPI was -0.56 which ranked 7th in the conference.

To refresh your memory, here are the 2008 Big 12 Standings.

Now here are the 2008 SDPI Standings sorted by total SDPI, with conference rank in offense, defense, and total SDPI in parentheses.

I'm a man who gives credit where credit is due, and it looks like the BCS got it right. Despite their head-to-head win over Oklahoma, in the other seven Big 12 conference games, the Sooners were simply more dominant than the Longhorns. Statistically, they were the best team and I have no problem with them earning the Big 12 Championship bid, and later the BCS National Championship Game bid. The Sooners offense was historically prodigious in 2008. In conference play, the second best offense (Texas Tech) was was nearly three quarters of a standard deviation worse, and the third best offense (Nebraska) was more than an entire standard deviation below the Sooners. Vehement SEC partisans might point out that Florida shut-down the mighty Oklahoma attack, but while the Sooners did gain a season-low 363 yards against the Gators, if not for two red-zone gaffes, they would have been in a great position to win the national title. Those same SEC partisans might also point out that Oklahoma put up those yardage and point totals against a set of Big 12 defenses that were not exactly rugged. It also bears mentioning that the other eleven teams in the conference also got to play those defenses. The Sooners separated themselves, at least offensively, from their conference brethren like few teams before them. Not surprisngly, as three teams in the division finished 7-1 in league play, the South was once again superior to the North as the top three and four of the top six teams resided in that division. What may come as a shock to some folks is that Nebraska rates out as the top team in the North. After being bludgeoned by Missouri on their homefield, on national television, by 35 points, the Huskers would lose only twice more the rest of the season--by six at Texas Tech and in embarrassing fashion at Oklahoma. Meanwhile Missouri would prove their pretender status, at least on the national scene, by dropping a home game to Oklahoma State, being blown out at Texas, and losing at a neutral site to arch-rival Kansas. Missouri certainly owned the Huskers in their head-to-head meeting, but over the rest of the Big 12 season, Nebraska was the better team.

Best Offense: Oklahoma 1.86
The most remarkable fact about the Okahoma offense is not how many yards and points they put up, but how many negative plays they avoided. Sam Bradford threw four interceptions and was sacked six times in eight Big 12 games. If we include the Big 12 Championship Game against Missouri, those numbers do not change. Two of those interceptions and three of those sacks came in the loss to Texas. I hope Mr. Bradford took his offensive linemen out for some quality steaks after he won the Heisman.

Think Dan Hawkins regrets leaving the cozy confines of Boise, Idaho?

Best Defense: Texas 1.30
Maybe this Will Muschamp character knows a thing or two about defense. Not surprisingly, the only game where the Longhorns really struggled defensively was the upset loss in Lubbock where the Red Raiders gained 579 yards.

Worst Defense: Kansas State -1.82
In other years, a performance like this could be enough to get the greatest coach in program history to make a comeback...

Hardest Schedule (based on cumulative SDPI of opponents): Baylor 5.29
The Bears played in the more arduous South division, meaning they had to play Oklahoma, Texas Tech, Texas, and Oklahoma State. In two of their three games against the North, they drew the best teams from that division--Nebraska and Missouri. All in all, they faced the top six teams in the conference.

Easiest Schedule (based on cumulative SDPI of opponents): Iowa State -4.58
If I wanted to fan the flames of the Gene Chizik hiring fiasco, I might remind you that the team with the easiest conference schedule went winless in Big 12 play. Obviously, they played in the weaker division, and in their games against the South, they managed to avoid the triumverate of Oklahoma, Texas Tech, and Texas.

Entire Schedule Strength (hardest to easiest)
Baylor 5.29
Kansas 3.60
Kansas State 1.34
Oklahoma State 0.86
Texas 0.27
Texas A&M 0.17
Texas Tech -0.25
Oklahoma -0.46
Missouri -2.77
Iowa State -4.58

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

South: Oklahoma or Texas
After my 'War and Peace' breakdown of the North, here's an abriged version on the South. Oklahoma or Texas have won the South every season since 1999. Texas Tech had their chance last season, and almost broke through. Unfortunately, the two biggest stars of that team, quarterback Graham Harrell and receiver Michael Crabtree, are gone. I'm sure Mike Leach will find an air apparrent under center and lead the Red Raiders to eight or nine regular season victories, but Oklahoma or Texas will represent the South in the Big 12 Championship Game.

The team(s) you should be buying are...

Iowa State and Kansas State

The team(s) you should be selling are...

Missouri and Texas Tech
I've already examined the myriad of personnel losses Missouri is facing heading into 2009, but I can't emphasize how much Missouri will miss those skill position players. A bowl bid is a distinct possibility, but definitely not assured. Texas Tech will also be breaking in new skill position talent, and it should also be noted that the Red Raiders were very fortunate in one-score games last season. Their victories over Nebraska, Texas, and Baylor were by a combined 19 points and were all decided late. If the Red Raiders were a little less fortunate, that 7-1 breakthrough is just another ho-hum 5-3. The home schedule outside of Oklahoma (and who knows, the Red Raiders have beaten the Sooners the past two times in Lubbock) is very winnable, but if Texas Tech breaks even on the road in conference play (Texas, Nebraska, Oklahoma State, and Baylor), 2009 will have to be considered a success.

The team(s) you should be holding are...

Baylor
Believe me, no one is rooting for the Bears more so then yours truly. However, Baylor's first bowl bid since 1994 will probably have to wait until at least 2010. For starters, despite showing substantial improvement under Art Briles, the Bears were still only the fifth best team in their division. Quarterback Robert Griffin certainly gives the casual fan a reason to watch Baylor. I know as a Wake fan, I am certainly glad Kirby Freeman started the opener in Waco. Still, even with Griffin, the Bears finished eleventh in the Big 12 in offense, beating out only Colorado. The bad news for Baylor is that they only managed two conference wins despite an outstanding turnover margin of +11 in Big 12 play (second to Oklahoma at +14). The primary reason for that great turnover margin was the fact that Baylor had only five turnovers in their eight conference games. Part of that was the efficient play of Griffin, who threw only three interceptions in conference play, and part of it was the fact that Baylor only lost six of their twenty fumbles on the season. Griffin will probably throw more interceptions in 2009 (see Colt McCoy in 2007) and the Bears will certainly fail to recover 70% of their own fumbles. More turnovers are bad for any team, but especially for teams operating at a distinct talent disadvantage like Baylor. Another factor, and this will be the case for the foreseeable future, is the schedule. The Bears four conference home games are against Oklahoma State, Nebraska, Texas, and Texas Tech, all of which are likely bowl teams. The road schedule is not much easier with trips to Oklahoma, Iowa State, Missouri, and Texas A&M on the horizon. The Bears did beat Iowa State and Texas A&M in Waco last season, but the Bears have just two road wins since joining the Big 12 in 1996! The non-conference schedule will give the Bears a chance at a fast start (Wake Forest, Connecticut, Northwestern State, and Kent State), but barring multiple league upsets, Baylor will be home for the holidays yet again.

Anonymous said...

Matt:

I don't get how this works. I see that SDPI is a good indicator of strengths and weaknesses LAST year.

But you say "This season, I'm sticking with yards only. The yardage version of SDPI has a better correlation with future performance than points,"

How is that so? In your predictions analysis for 2009, you don't mention yardage SDPI at all. When you mention teams that we should be buying and selling, you discuss mostly roster changes or schedule strength. I don't see yardage SDPI being applied. If the 2008 yardage SDPI is a good predictor of future strength, then it's telling us that the Big 12 team wins and losses will be the same as last year, right?

Again, I see how this gives insight for last year, but I don't see yardage SDPI, or any other SDPI for that matter, predicts future performance.

matt said...

I beg to differ. I mention where a team finished on either offense or defense numerous times (this is a reference to the table near he beginning of the post that liasts their SDPI finish).

There's more to analyzing a team than their overall record. Yardage is a good indicator of how a team performed on a down-to-down basis.

To summaraize my 4 biggest points from this post were as follows:

1. Nebraska was the best team in the North last season (despite not winning the division) and should be favored to win in 2009.

2. Iowa State, despite a winless season, was far from the worst team in the division. When they challenge for a bowl game in 2009, don't be shocked.

3. Kansas State, despite an 'NFL' quarterback, was below average on offense. His departure will not hurt the team as much as expected.

4. Baylor, despite the play of Robert Griffin, was significantly below average on offense. Their high turnover margin is not likely to be repeated and they will not improve in Art Briles' second season.

Plus not using schedule strength and roster attrition/addition would be just plain stupid. SDPI is a better predictor of future performance than won/loss record, but of course it is far from perfect. That is why we watch sports: the outcome is undecided.