Weekly Roundup

The two big topics in football stats this week were the BCS and the NFL overtime rules. I've already had my say on OT rules, so let's start with the BCS.

Baseball analyst Bill James made a minor splash with an article urging a boycott of the BCS system by quantitative analysts (Hat tip--PFR). His fourth point is very interesting and goes against conventional wisdom. The BCS is not the result of big conference and big school greed. James says that we would have a Division I playoff system now except for the fact that the large number of small and uncompetitive schools would vote to share the playoff revenue too broadly.

Maybe so, but there is an underlying problem with college football. It's an unstable system. In systems engineering terms, the best example of a stable system is a thermostat. If it gets too hot, the thermostat kicks in to make it cooler, and vice versa. The NFL is a stable system. A team with a top record is rewarded with lower draft picks and a tougher schedule. A team with too many top players will lose some in free agency. But in college, the effect is reversed. College football is like an anti-thermostat. Imagine a room in which the thermostat turns up the heat the hotter the room gets. College football works the same way.

A successful football program will get money, attention, television time. This will lead to better recruits and even more wins. In turn, there's even more money, big name coaches, and better recruits. And every top recruit on one team's roster is a recruit unavailable to competitors. That's why every year we see the same handful of schools competing for championships. Oooh, I can't wait to find out who the 2009 champion is going to be. Will it be USC, Florida, LSU, Texas, Oklahoma, or Ohio State? The suspense is killing me!

While James' point may be true, it's nearly impossible for most schools to become competitive. Maybe the only way to stabilize the system--to create some semblance of competitive balance--is to spread the wealth.

Also on the college front, the Numbers Guy points out that special teams success does not necessarily correlate with winning.

"ZEUS" thinks the Colts should have taken an intentional safety at the end of regulation in their losing effort at San Diego. ZUES is software built by a couple of PhD-types that aids sideline decision-making, such as when to kick or go the 1st down or when to decline a penalty. It's very similar to the win probability system here (except that they're trying to sell it to teams for over $100,000. Good luck with that. Psst Mr. coach, you can have mine for half the price.)

Reader Ed Anthony emailed me to suggest this Monday, but I dismissed the idea too quick. I was going to do up an analysis to prove that ZEUS was wrong. It seemed obvious to me. Taking the safety turns a SD field goal into a game-winning kick instead of a game-tying one. A safety would have made a FG slightly less probable because it would have given the Chargers worse field position, but not nearly enough to risk the loss instead of the tie. What I left out of the analysis is that it also makes a touchdown less probable. And even though a TD would have been fatal in either case, making the TD less probable makes taking the safety a slightly smarter move. It doesn't matter that the TD didn't occur, it would have been the better decision at the time. Good instincts, Ed!

Doug Drinen at PFR looks at whether specific types of match-ups disproportionately affect game outcomes. Suppose there are two equal teams overall, but there is one particular facet where one team is much stronger than the other. Is it decisive? It's a complex question.

A couple years ago, I looked at the same issue but in a different way. I added interaction variables to my game predition regression model. I used all the same efficiency variables I usually do, but added additional factors such as [offensive run efficiency * opponent defensive run efficiency]. I was testing whether any particular match-up of team qualities had a non-linear effect above and beyond just a linear additive effect.

To put it simply, teams just don't put their abilities up on a table and let them play out independently. Team strengths and weaknesses interact with those of their opponenets. I was testing those interactions to see if they were significant. Some were, but the effect was very slight. The model was no more accurate and was far more complex than my original, so I abandoned its use in 2006. Now that I have a lot more data, it might be worth a revisit.

JKL, also at PFR, looks at older QB performance in the latter part of the season. This is a response to what FO looked at last week. The PFR analysis is far more comprehensive and does find a late-season effect. Also check out JKL's clever idea on revamping overtime.

Sometimes, this weekly roundup post turns into a cross-link-fest with PFR, Sabermetric Research, and Smart Football (which features some great college analysis this week). So there's plenty of room for fresh blood. I haven't mentioned it in a while, but the Advanced NFL Stats Community site is up and going strong. There's a new post once every couple days, and the site gets a few hundred visits every day. All contributors are welcome, so if you have an idea you'd like to share, or even just an opinion on stats in the NFL, please join in. There is data available for anyone who wants to kick it around.

Dennis O'Regan has two posts, one on how Baltimore's defense travels (I'm guessing it travels just fine!) and another on starter vs. backup QBs. Derek Singer looks at what kind of teams win championships. Josh Fryman has some observations on how regular season records may not be predictive of playoff success. Bob Burns wonders how a prediction system that doesn't account for wins can actually predict winners. Doug and Patrick Walters share their technical-financial-based system for predicting team fortunes.

Lots of activity this week. Enjoy the best NFL weekend of the year, and don't forget to check out the Win Probability site during the games. There's a special offer--this weekend only--get $100,000 off your first 5 visits!

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6 Responses to “Weekly Roundup”

  1. Anonymous says:


    I've been doing a prediction/analysis blog on this year's playoffs and I was hoping you might be able to help me out with some stats. Can you possibly tell me what the record is for teams going against the same team they have already beat twice during the reg. season?

    I think that "It's tough to beat the same team 3 times in a season" angle that always gets played up is really overplayed, but I'd like to see some actual data on it.


  2. Brian Burke says:

    Kelly, I share your instincts with the hard to beat 3 times angle. But I don't have that data handy. I always start with pro-football-reference.com. About.com and nfl.com have regular season and playoff game outcomes for the past few years.

  3. Tarr says:

    The inbalance of NCAA football is only a problem if you think it is. I know that sounds a bit like a zen riddle, but really, is it an issue if Indiana never wins the NCAA championship? Why should they care? They make money putting people in the stadium, and they play a season every year.

    It used to be the same way in professional sports, too, before the era of salary caps. Baseball, and international soccer, still have these haves and have-nots, although the nature of these sports (that the less talented team wins a much higher percentage of games) makes this more palatable. And basketball has so few players at a time that dynasties arise despite all the balancing effects. All in all, there's not much evidence that dynasties hurt a sport's popularity.

    JKL's proposal for overtime is not very much different than my "whoever has the ball at the end of regulation wins the toss" approach. It's certainly more fair, but I'm not sure it's worth all the extra complication. And the "just keep playing" approach is simpler and more fair than either of them.

  4. Brian Burke says:

    I hear you on the Zen thing. I agree, and that's why college football keeps going on despite the concentration of talent.

    But don't you think Indiana would be thrilled with competing for a national championship? Wouldn't its stadium be expanded, its ratings increase, and revenue enhanced by having a legitimate contender?

    There's a theory in sports economics that the best players will find their way to the big markets with or without free agency--Reggie Jackson to the Yankees, for example. Maximizing utility sometimes means making the most people happy, so the team with the most fans (with the most money) will ultimately win out.

    (My own school, Navy, basically uses its football program as a visibility/recruiting tool. They are satisfied with a winning record and bowl invitation every year. It's why they like being an independent. They play a national schedule against different schools every season. There's always high school kids out there who see a Navy score and say "What's the Naval Academy? Oh, it's a college. That's where Navy and Marine officers come from. Cool.")

  5. Jason says:

    A friend of mine mentioned that he saw the ZEUS piece on HBO a couple of weeks back, and my first question to him, "Is it by that guy who does Advanced NFL Stats?"

  6. Anonymous says:

    Thanks anyway Brian,
    I actually found your site while looking for stats to back that up. I thought maybe you had some really good source for stats based on the name of the site. Anyway this is what I went with:

    "By now, you've heard plenty about how hard it is to beat a team three times in a season between now and gametime, but that is one of the most overblown stats in football. There are several reasons it doesn't happen often. First, most teams don't play each other twice in the regular season. Second, there are only three chances for two or more teams to make the playoffs (1 div. winner, 2 wildcards), so not all divisions have more than one team in the playoffs. Third, A team that is good enough to make the playoffs is less likely to get swept by a division rival. Fourth, there are at least four and more often five other teams outside your division within the same conference bracket, making it that much more unlikely for a team to be matched up against a team they already beat twice. I'm not a statistician, but I surely can figure out that, based on all those factors, the difficulty of beating the same team three times in a season has alot more to do with a lack of opportunity than it does with the actual ability of a team..."

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