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Yards Per Point Margin and Luck in the SEC

All data from I-AA games has been thrown out for this post.

One of my favorite measurs of team efficiency is yards per point margin. It has two components: "offensive" yards per point and "defensive" yards per point. I put those terms in quotes because they involve in offensive and defensive stats, but they don't only pertain to what the offense and defense does.

Offensive yards per point is total offensive yards divided by total points scored. The lower that number, the less offensive effort your team has to exert to get points (generally). If your defense or special teams score, that ratio goes down. If your defense returns turnovers or special teams return kicks and punts long distances, that ratio goes down. That's why it's about more than just offense.

Defensive yards per point is total defense divided by total points allowed. The higher that number, the harder your team made it opposing teams to score. A terrible offense and bad special teams can impact this one, which is why it's more than about just defense.

If you subtract the offensive number from the defensive number, you get yards per point margin. The higher the number, the more efficient you were as a team. Here are where the SEC teams ended up in YPPM, how it compares to a rough projected record (by pairing YPPM rank with all of this year's won-loss records nationally), and I threw in their luck as determined by Pythagorean expectation.

Team OYPP DYPP YPPM Record Proj. Record Luck
Alabama 13.45 20.91 7.45 8-3 11-1 -1.50
LSU 11.85 16.75 4.90 9-2 10-1 0.90
South Carolina 12.46 15.51 3.05 8-4 8-4 -0.07
Auburn 11.85 14.88 3.03 12-0 8-5 2.72
Georgia 12.01 14.37 2.36 5-6 7-4 -2.24
Mississippi State 15.09 17.40 2.30 7-4 7-4 0.28
Florida 12.33 13.83 1.50 6-5 6-5 -0.91
Arkansas 13.25 14.41 1.16 9-2 6-5 1.06
Tennessee 14.06 15.00 0.94 5-6 6-5 0.00
Kentucky 13.67 12.39 -1.28 5-6 5-7 -1.01
Ole Miss 13.54 11.89 -1.65 4-7 4-7 -0.49
Vanderbilt 17.63 13.45 -4.18 2-10 2-10 -0.28


A quick primer on these stats. An OYPP value of less than 12 is very good. A DYPP value of more than 18 is also very good.  A YPPM of 10 or greater is outstanding. The higest YPPM of the last decade was 2001 Miami (10.51 OYPP; 28.93 DYPP; 18.40 YPPM). That team also had the best DYPP. The best OYPP was 2002 Kansas State's 9.45.

As far as luck goes, if it's between 1 or -1, I don't consider it a big deal. Once you get above 1 or less than -1, I start to get interested.

Alabama was the most efficient team in the conference by this measure. The Tide was even fourth nationally in it too. It should have had a better record, but you'll note that the team had bad luck. It's not hard to figure out where that comes from when two of Bama's losses were by a field goal or less while only one win was by a single score.

LSU actually tied Auburn for lowest OYPP, which shows the divergent ways to get there. LSU largely got there thanks to great special teams and defense. Auburn largely got there by not wasting possessions with punts and turnovers. Georgia ended up third, which goes to show how much UGA's special teams improved and how fairly efficient its offense came to be. Florida was fourth in the conference for largely the same reasons that got LSU the top spot. Lots of very short drives also helped keep Florida's OYPP low, which shows a flaw in the stat. It doesn't correlate exactly with winning, after all.

Mississippi State finished second in DYPP, which given the Bulldogs' mediocre OYPP score, shows what a great job Manny Diaz did in Starkville this year. I don't think he's getting the credit he deserves. Unsurprisingly, Ole Miss was dead last. in DYPP. Not only was the Rebel defense bad, but the offense and special teams didn't help it out a whole lot to compensate.

Besides Alabama's, only three other teams' records differ significantly from their projected. Two are easy to understand. One is Auburn, who is the second luckiest team in the nation according to Pythagorean expectation. If you win all six of your close games, the numbers are going to project your to have a worse record. That's a guarantee. The other is Georgia, who ranks as the fourth-most unlucky team. When you tend to win big a lose close, that's a side effect.

The final one is Arkansas, who projects to have a much worse record but doesn't rate as all that lucky. If I had to guess, I'd say it has something to do with having a lot of lost turnovers and being last in the league in both kickoff returns and kickoff return defense. I'm going to have to study that a little more this off season.