The Weekly League: Notes and Ideas for Week One

Five notes before we begin:

1. Thank you times a thousand to Brian Burke. His site is crazy good. It's my ambition not to destroy it.

2. Below are previews of two upcoming games: Thursday night's between Minnesota and New Orleans and the Monday game between San Diego and Kansas City. These previews aren't intended to be exhaustive, by any means. (In fact, the attentive reader will notice that there are only, like, 10 words dedicated to the Chiefs.) Rather, the intent is to construct a lens through which to watch these games -- hopefully something that your local paper isn't gonna provide. I discuss this more fully in the introduction thing near the end.

3. Oh yeah, there's an introduction thing ("Introduction-as-Epilogue") near the end of this document. It explores more fully the theoretical underpinnings to this document. If it makes you throw up, I apologize.

4. For each game, you'll see not only the day and kickoff time, but also -- below that -- something called Four Factors. The Four Factors are an attempt to express each team's offense and defense relative to league average. So, OPASS+ is offensive pass efficiency relative to league average. Their 111 OPASS+ means that Minnesota passed the ball 11% more efficiently (measured by net yards per attempt) than the league-average team in 2009. Likewise, DRUN+ is that team's ability to stop the run, also relative to league average. Numbers over 100 are always a good thing. So when you see that Minnesota had a 107 under DRUN+ in 2009, that means that they stop the run 7% better than league average.

5. Let's get it started in here.

Minnesota at New Orleans | Thursday, September 09 | 8:30pm ET
Four Factors


The Anti-Freak Out
Let's hope that if I do one thing right during my stay in these electronic pages, it's to explicity not freak out about Brett Favre. Or, how about this: if I do freak out about Brett Favre, it'll only ever be for the right reasons.

Brett Favre-related stories are probably the worst thing about football, as they provide mainstream media infinite opportunity to speculate wildly. Wild speculation, regardless of context, is wildly unbecoming. And yet, for the last four or so offseasons, we hear the same story, repeated ad nauseam.

• "I have it on good authority that Brett Favre will be returning to the NFL this fall."
• "I have it on good authority that Brett Favre will not be returning to the NFL this fall."
• "I have it on good authority that Brett Favre descends from a race of cannibal people and has a hunger that's sated only by the taste of human flesh."

Those are all equally plausible stories in July.

A Note on Adrian Peterson
If you're (a) a devoted fan Adrian Peterson's and (b) much bigger than me, please stop reading right now.

Pretty please. Do it.

Okay, now that those types of people are gone, here's the thing I'm gonna say: Adrian Peterson wasn't that valuable last season. "But, Cistulli," maybe you're saying, "he rushed for over 1500 yards." Or "Cistulli," maybe another one of you is saying, "don't you even know that he scored 21 TDs last year?"

Yes, I realize those things. But I also realize another thing: running is, in almost every case, less effective than passing. And I realize a third thing, too: for all his time with the ball, Peterson added exactly 0.1 Expected Points (EPA) last season and posted only 43.0% Success Rate (SR).

By comparison, teammate Jeff Dugan, the target of six total passes all year, was more valuable, compiling a 2.9 EPA.

A Second Note on Adrian Peterson
Obviously, there's a difference between value and talent. The latter is largely the province of the player himself; the former, how said player is deployed.

Adrian Peterson is a talented football player. He has over 1500 muscles, can run the 40 in -1.3 seconds, and -- honestly -- is a lot of fun to watch. Those are all true things.

Also obvious is that, as players are involved in larger and larger percentages of their team's possessions, so too will they becomes less efficient on a per-play basis. Even so, that didn't prevent Chris Johnson (49.7 EPA) or Ray Rice (23.8) or Jonathan Stewart (22.9) from tallying large-ish Expected Point totals.

Did those players have better run-blocking ahead of them? Maybe. But also: it doesn't matter. The Vikings averaged only 4.1 yards per run last year; the league average was 4.2. Meanwhile, the team passed for 6.9 yards per attempt; the league average was 6.2. During "normal" football (i.e. 1st and 3rd quarters, within 10 points either way of their opponents), Minnesota passed 58% of the time -- only 15th most often in the league.

Very Tentative Conclusion
The Vikings aren't using their awesome weapon in the best way possible.

Also: it'd make a lot of sense for the Vikings to pass more (although, admittedly, Sidney Rice's injury complicates this matter).

Question
Is it almost a burden for a team to have a great running back -- on account of they feel the need to (over)use him?

I don't know the answer, but it seems like a distinct possibility.

Something the Saints Will Do
Be awesome offensively.

Last year, the Saints averaged 6.3 yards per play -- tied with the Cowboys and pretty far ahead of everyone else. There are a lot of reasons to think they can stay near the top of the leaderboard in 2010. They featured above-average passing and running attacks and, unless you think that Mike Bell was responsible for the largest part of the team's success -- well, then the Saints are gonna bring it pretty hard.

Something the Saints Won't Do
Score 510 points again.

Last year, the Saints had 5 TDs from interceptions and 2 TDs from fumbles -- and had 9 TDs total from events other than offensive passes or rushes. The league average for those "other" TDs was 3.4 per team last year. Hardly any of the elements that contribute to these other sorts of TDs are considered "repeatable skills." If the Saints score, you know, exactly 35 fewer points this season, that'll probably be why.

San Diego at Kansas City | Monday, September 13 | 10:15pm ET
Four Factors


Searching for Vincent Jackson
Whether because of his physical attributes, his instincts, or his understanding with quarterback Philip Rivers, the fact remains: Vincent Jackson has been super good at catching footballs for the past couple years. Only problem is, he'll also probably be absent until Week 10. Consider this: last season, Jackson tied for second (with Minnesota's Sidney Rice, behind New Orleans' Robert Meacham) in EPA/P with 0.71 and second (behind Rice) in total Expected Points Added, with 82.6. Consider this other thing: despite the fact that, for each of the last four years, his rate of Deep targets (15 yards or more) has generally increased, his Catch Rate has, too (46.6%, 49.4%, 55.1%, and 63.6% over the last four years). That's good.

Replacing Jackson as the team's No. 1 receiver will be Malcom Floyd. Floyd was quite productive on a per-play basis in 2009, posting a 0.52 EPA/P -- right between Miles Austin and Greg Jennings by that measure (albeit with fewer targets than either). Exactly 50% of Floyd's targets were of the Deep variety, placing him second among all qualified receivers by that measure. It seems unlikely that Floyd will reach either mark this season. In Jackson's absence, he'll receive more attention from opposing cornerbacks. Moreover, with an increased load, he's likely to be targeted more often within 15 yards of scrimmage.

On account of I'm not that smart, it would be impossible for me to do it, but a good study would be to find the average decline in EPA/P for receivers who "graduate" from No. 2 to No. 1 receiving status. It'd probably have to be adjusted by the talent of the departing No. 1, but it seems like something that's worth studying.

Run-Pass Imbalance
The attentive reader will note that San Diego last year posted a kinda crazy imbalance in their pass/run efficiency (8.1 pass versus 3.3 run yards per attempt, respectively). Despite the incompetence of their running game (the second-least efficient in the league), the Chargers still managed an impressive 5.9 yards per play -- good for third in the NFL.

One can't help but wonder, though, how much better that offense would've been had coach Norv Turner and Co. not given LaDainian Tomlinson 223 rushes. Consider this, for a second:

NFL Avgs (2009)
Plays: 1006.9
Pass: 566.7 (56.3%)
Run: 440.3 (43.7%)
Yards/Play: 5.3

San Diego Avgs (2009)
Plays: 972
Pass: 545 (56.1%)
Run: 427 (43.9%)
Yards/Play: 5.9

As you can see, the Chargers ran about as often as a league-average team while possessing a considerably above-average passing and considerably below-average running game.

The Chargers, Passing, and Normal Football
Turns out, San Diego's play-calling wasn't so abysmal as the raw numbers show. If we look at what Mr. Burke calls "Normal Football" -- that is, those periods in the first and third quarters when the score is within 10 points -- we see that the Chargers were actually more pass-heavy than at first glance, going to the air a full 61% of the time. That's a good thing for San Diego.

It remains to be seen how Turner will go about his play-calling with the young and relatively spry Ryan Mathews now in the fold. If anything, there's likely to be more running.

Obligatory Note About the Chiefs
It's a fact: the Chiefs are the other team playing today.

Introduction-as-Epilogue
In which the author pontificates as hard as possible.

Asking the Right Questions
In these pages, a little over three years ago, our esteemed host Brian Burke wrote the following:

Who has the longest interception return ever? Which running back ran for the most yards in a single game? What team scored the most fourth quarter touchdowns in a season?

Answer: I don't care.

That's trivia, not statistics. What I'm interested in is analysis. What makes a winning team? Is it better to go for it or punt on 4th and short at the 50 yard line? Which teams are most likely to make the playoffs? How much does luck play a part in any game?

Because you're the sort of person who points his (or her) browser to these electronic pages, you're likely aware that Brian spends much of his time asking the smartest possible questions he can and then attempting to provide answers. That's a good way to go about things -- not just in football analysis, but in life.

You're also likely aware that there's a lot of football coverage around these here internets that concerns itself neither with answering questions responsibly, nor even with asking questions in the first place. That's a bad way to go about things.

It's Brian's commitment to asking questions that's made me such an enthusiastic reader of his site, and it's what's got me excited about contributing to the same.

Numbers as Narrative
Simply because we deal with numbers here doesn't mean we ought to ignore words. In fact, numbers are at their best when they acquire the power of words.

Don't take my word for it, though. Here's Bill James, Father of Sabermetrics, from one of his Abstracts:

When the numbers melt into the language, they acquire the power to do all of the things which language can do, to become fiction and drama and poetry. Am I imagining things? Do not the numbers of Ted Williams detail a story of fierce talent and, by the char of their ugly gaps, the ravages of exquisite frustration that ever accompany imperfect times? Do not the numbers of Roberto Clemente spell out a novella of irritable determination straining toward higher and higher peaks until snapped suddenly by an arbitrary, but now inevitable, machina? Do not the stressed and unstressed syllables of Willie Davis‘ prime suggest an iambic indifference Is there not a cavalcata in Pete Rose’s charges? Is there no union of thrill and agony in Roger Maris‘ numbers? How else can one explain the phenomenon of baseball cards, which is that a chart of numbers that would put an actuary to sleep can be made to dance if you put it on one side of a card and Bombo Rivera‘s picture on the other.


What James suggests is that, rather than destroying narrative, the numbers -- or, the correct numbers, at least -- are able to construct narratives that are otherwise invisible. The numbers give us stories we didn't even know were there, really.

As I write, ESPN's SportsCenter is promoting a story they'll run later about Matt Leinart -- the same Matt Leinart who has spent the majority of his NFL career as a back-up quarterback. Obviously, that's not an entirely meaningless story: Leinart was a great college player and won a Heisman, but has disappointed as a professional.

But the real reason Leinart is in the news is because of his off-the-field exploits. Like the time he got photographed drinking with hot and mostly naked coeds. And like the other time he got photographed drinking with hot and mostly naked coeds. The point is: Leinart isn't so much an interesting player as he is a personality. That's fine. There's nothing explicitly wrong with that. But it also doesn't really have a lot to do with him being a football player. Really, that's just how he got famous to begin with.

The numbers, though, tell stories about the action on the field: that passing is probably the best way to win; that, despite being just a mound of ice cream and hot dogs, Albert Haynesworth was actually pretty good last year; that Jared Allen is as much of a man-beast as he appears to be. It's nice both ways: when long-held truths are upended by evidence, or when the data reinforce what we suspected already.

Game Narratives
I like watching sports. I like watching sports a lot more when I know what to look for, when there's a lens through which to watch a specific game. My work at FanGraphs deals mostly with constructing these lenses, of identifying a player or situation of interest to the reader/watcher.

Basically, that's what I intend to do here -- and, hopefully, have done above. It's possible that, in future weeks, I'll address more than two games. It's very possible that I dwell on each game for fewer than 800 or so words. However it works, the intention will always be the same: to make the game more interesting for people who both (a) like football and (b) respect the scientific method. Oh, and if you ever wondered how a foul-mouthed 7-year-old might write, that'll be available here, too.

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20 Responses to “The Weekly League: Notes and Ideas for Week One”

  1. Alex says:

    Good start.

  2. Jeremiah says:

    A quibble; Peterson may have been quite valuable if we assume that A) most other running backs would have been horrible behind the same line and B) the Vikings were going to be running the ball a lot no matter what. Is condition A true? I can only guess, but it certainly is my impression that Peterson generates a lot more long runs than most running backs are able to. But I agree that your overall point is more important; the Vikings should have been throwing more.

  3. Anonymous says:

    So much of the analysis I see on this blog confuses average values with marginal values. For example, the high average net yards per pass is interpreted as a reason to pass more. I'd believe this if I saw some analysis that showed the marginal value of passing higher than the marginal value of running, but simple averages don't do it. The marginal value is situational dependent and includes time remaining, variability of outcomes, opportunity costs, as well as game theory (what strategy your opponent chooses).

    I'm stunned that Cistulli compares the average values of Adrian Peterson's plays (a large sample size) with players of higher averages but a very low sample size (Jeff Dugan with a sample size of six). By this logic, Clint Longley is a better quarterback than Roger Staubach because of his famous Thanksgiving game.

    Adrian Peterson's yards might be low because he runs the ball on third and short and helps to run out the clock at the end of games. The marginal value of two yards when it's third and one is quite high. Many coaches would take a certain two yards over a play that averages four yards but has a wide range of outcomes. Also, Petersen might be used a lot so as to increase the marginal value of passing--defenses have to expend resources in stopping him, leaving more opportunities for passing. If you only use him two or three plays a game, there isn't much reason to design a defense to stop him. You can concentrate on Favre's passing.

    I'm a newcomer to this blog, but I'm not convinced yet about all the rah-rah about passing. I agree that the rule changes have made passing marginally more attractive, hence the rise in the percentage of pass plays in a game over time. Maybe there should be more passes, I'm very open to the assertion (particularly with even more rule changes that help the passing game), but don't cite average values to prove it. Optimization theory involves marginal, not average values.

  4. j holz says:

    More please

  5. Ian says:

    Anon - It's a good point about how things are at the margins, but I think one of the assumpions we make is that of repeatability i.e. if I run the same strategy I should get the same outcomes. For example, if I've already run a 50:50 split of plays for the first 8 games and got 6 yards per pass and 4 yards per rush, I expect to get the same stats if I run a 50:50 split for the remaining 8 games.

    At the margin, we're concerned with how the next play will go. But if I assume my past performance is indicitive of future performance then the expected value of the next run/pass will be either 6 or 4 yards. This isn't a bad assumption really - after all, if a 50:50 split have so far given me 6 per pass and 4 per run, we have more reason to suspect this in the future than some other values (for example, there's no reason for my passes to suddenly start to average 4 yards if I change nothing).

    Your point is not invalid though. That's why, when sites like these say "passing gets more yards than rushing, therefore we should pass more" they never actually say exactly what run/pass balance to go with. You can't tell what would happen to a team's passing efficiency if you change their strategy mix. But the point about using averages is that it collects all the 'margins' from previous plays run under the previous strategy, giving an indicator of all the past margins. In the future, with the same strategy, we expect the same margins again.

  6. Brian Burke says:

    Re: marginal vs. average

    In football, marginal utility is the "next expected gain" from a certain type of play or by a certain player or team. Averages, for the most part, do the trick. They can be represented in many ways (yds, EP, WPA, etc.). The great thing about EP and WPA is that they are linear utility curves, and therefore next expected = marginal.

  7. Anonymous says:

    Are you guys going to be doing the weekly picks like last year that ran on NYT? Those projections turned out great and were a huge asset towards me winning many a pool last year.

    Also really like the format of this write up. Look forward to it this year.

  8. Brian Burke says:

    Game probabilities will be running this year. I need to wait for a couple wks to go by to get some decent data, however. They will likely be at NYT again, either the print or online edition. I'll link to them here either way. Still not sure, though. My agent, Drew, is telling me to hold out for more money and another guaranteed year, but Toni Monkovic is no Dan Snyder.

  9. Andy says:

    @Brian about marginal vs. average:

    This cannot be quite right. Or more precisely, if you're correct, and the average is everywhere the marginal, then advice cannot be "pass more", it must be "pass exclusively".

    That is, when people talk about run/pass mixes, they are implicitly assuming some form of diminishing returns so as a team runs more, it becomes less and less effective. Or, the marginal value is different (below) the average value.

    To respond to another comment by the first anonymous, I absolutely agree about incorrect comparisons of averages of two groups that have different sample sizes, although I think the problem is more fundamental than the selection/game theoretic issues Anonymous raised. It is just basic statistics that the variance of averages are declining in sample size. Comparing low carry RBs to high carry RBs without adjusting for the change in degrees of freedom will lead to erroneous conclusions.

  10. Brian Burke says:

    Agree on the sample size point. This is how I think about marginal vs average in football:

    Football is very artificial in its construction. The marginal cost of any one play is always the same: one down. The marginal production is what's coming next. The question is, how do we estimate that? What is the best practical measure of expected future performance available to us? The average.

    And as I mentioned above, the marginal utility of a thing differs from its average utility only when the utility curve is non-linear. In most cases here (EP, WP, etc.), the utility curve is a straight line. In other cases (game prediction model), I use a logistic probability curve, so that very high inputs in a model diminish in effect as teams would theoretically approach a 1.000 or 0.000 winning percentage.

    Keep in mind teams are not acquiring a basket of goods. Teams do not grow tired of gobs of extra running yards during a season because they already have a lot of them, the same way I might get bored with a bunch of extra TVs in my house. The first TV is great. The second is convenient. But after that, I'm just looking for places to put them and would prefer having a laptop or some other good to another TV.

    I'm not an economist, so maybe I'm off base. But someone will have to explain it to me.

  11. Andy says:

    Brian, it sounds like your understanding is generally right about the average vs. marginal issue, although I would say the real problem is lack of a model to inform our data. We do not know exactly the 'production technology' (in economics lingo) of runs versus passing. That is, we do not actually know or observe the full payoff matrix of the offense/defense game where by full, I mean literally every possible choice.

    So we're stuck using data to estimate a much much simpler model. In estimating, we make an assumption that the average will give us a good guess of the marginal. This assumption is bad (there are obviously diminishing returns), but it is the best we can do without making ridiculous assumptions about the functional form of the payoff matrix.

    I think the right way to present this is to admit that marginal vs. average distinctions may be problematic, but that given our limitations, this is the best we can do.

  12. Andy says:

    About the linearity of the utility curves, it isn't clear to me why EP or WP have linear utility. The argument against EP entering utility linearly is just that if I care about winning a game, then EP must have a very nonlinear relation to winning depending on the current point differential. If you're already up or down by a ton, one EP has a low marginal benefit, whereas in a close game, one EP has a high marginal benefit.

    Perhaps it's different if you're considering EP over a season instead of over a game.

  13. Brian Burke says:

    Would love to know the underlying payoff matrix, or at least how the coaches perceive it.

    On a related note about the value of average--It's finally sunk in with me that that average running gains (yds per carry, or even EPA/carry) may be a very poor measure of the effectiveness of a running game. More in a subsequent post.

  14. Brian Burke says:

    In engineering terms, it's a matter of where you draw your system boundaries. EP is linear under the assumption that on any particular drive, a team's goal is to maximize its expected net point advantage.

    There are obviously parts of the game where that breaks down, like toward the end of a game, when you don't care whether you win by 1 or by 100, (which is why Carson limited some of his analysis above to the first 3 qtrs with the score w/in 10 pts).

    That's where WP comes in. WP is always linear within the system boundary of the game as a whole. A WP of 0.40 is always twice as good as a WP 0.20. And a WP of 0.80 is always twice as good as a WP of 0.40.

  15. Andy says:

    Yeah, I think you're right. Most of the time, we can utility is approximately linear in EP, with the notable exceptions being times when you become a lot more risk-averse.

    And I do agree that WP is linear, or at least as far as we're concerned. The cute side of little economist me wants to point out that it's not clear exactly what the owners or coaches are maximizing or that we don't know how WP feeds into an owner's profits, but linear WP sounds right.

  16. Ian says:

    I can't wait for this post on Brian's new thoughts for measuring the effectiveness of the running game. Should be interesting - any sneak previews?

  17. Brian Burke says:

    The sneak preview is that I underestimated the importance of running by looking at average efficiencies. (I was wro...wro...wro...ng.) I think I finally figured out what coaches are maximizing, since they don't appear to be maximizing yards, net points, or even WP. I also found solid evidence of minimax play in the run/pass mix, where we could find none before.

    That's not to say, coaches are doing things right after all. It's that I think I have zeroed in on what they are maximizing.

  18. Ian says:

    "YEAHHHHHHHHHHHHHHHHH!!!"

    Oops, sorry, a bit of a CSI Miami moment there.

    "I think I have zeroed in
    *puts on sunglasses*
    on what they are maximising"

  19. Brian Burke says:

    I was going more for the Fonz. (Actually, I'm trying to go for the House thing. Total jerk, but you can't ignore his analysis.)

  20. Anonymous says:

    Here's another application of marginal vs. average values. A new player doesn't have to be above average to help make his team better. He just has to be better than the player he is replacing. He can still be the worst player on the team, but as long as he is better than the player he replaces (who in this example, obviously was the worst as well), he has raised the team average.

    Yes, a player can be below average when joining a team, but still bring the average quality of the team up.

    The reverse happens, too. This is probably easier to understand. A superstar that suddenly leaves and is replaced by a mere star means the average quality on the team went down even though the new player is above average at his position.

    In both cases, it's the marginal value of the player that counts, and the marginal value depends on circumstances. In this case the marginal value is determined by comparing the value of the player with the value of the player being replaced, not their value compared to averages.

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