"Football Freakonomics": Is Momentum a Myth?

The following is a cross-post from NFL.com, where we’ve recently launched a Football Freakonomics Project.

Is momentum a myth? That’s the question we ask in our latest installment of Football Freakonomics. It’s the kind of topic that academic researchers are increasingly interested in – and  the kind of topic that makes a lot of sports fans hate academic researchers.

Why?

Because they take all the fun out of our arguments! Do we really want to haul out a spreadsheet to talk about whether Mike Smith was a bonehead for gambling on 4th down? Or whether icing the kicker is a good idea?

As someone who has one foot in both camps (fandom and academic research), I can see both sides of the argument. In the case of momentum, however, I really want to know the truth – perhaps because it’s the kind of phenomenon that is harder to prove than most.

The best place to start is with a famous (for academia) paper from several years ago, called “The Hot Hand in Basketball: On the Misperception of Random Sequences.” As you can glean from that snazzy subtitle, the authors come down against momentum, arguing that a “hot streak” is really just a random sequence that we misperceive to be more meaningful than it is. 

Ever try flipping a coin 100 times? You’ll be surprised at how many long, unbroken sequences of heads or tails you get. It’s easy to mistake that for a pattern, suggesting some kind of meaning or momentum, but it’s really just a pure illustration of randomness itself. The fact is that if you get 10 heads in a row, the next flip is no more likely to be heads (or tails, for that matter).

And so it is, for the most part, with hot hands and hot streaks and hot quarterbacks. In our Momentum video, you’ll hear Toby Moscowitz, the academic co-author of Scorecasting, discuss how pretty much everyone in football believes in momentum. But, having looked at a lot of NFL data, Moscowitz reaches a sobering conclusion: “There is a much stronger belief in momentum than is warranted by what we see in the data.”

In other words, just because a team has driven down the field three times in rapid fashion to set up a dramatic comeback doesn’t necessarily mean the fourth drive is sprinkled with fairy dust.

Here’s the takeaway: we should be leery of announcers (and coaches and players and fans) talking about “the Big Mo” as if it were a twelfth man who suddenly snuck onto the field and is about to streak, uncovered, into the end zone.

Why, then, do so many of us believe that the Big Mo is a monster?

Consider one example in our video, the Buffalo Bills’ redonkulous 32-point comeback against the Houston Oilers in 1993. As Chris “Mad Dog” Russo puts it: “You’re gonna tell me momentum had nothing to do with that game?!”

Okay, Chris, I’ll take a shot at telling you exactly that. You know why we’re still talking about that game? Because it was a massive anomaly – the kind of comeback that almost never happens. It was so rare that our brains have an easy time recalling it. (We do this with all anomalies – dramatic plane crashes, mass murders, and so on.) And when we recall something so easily, we tend to believe it’s far more common that it actually is.

The truth is that you’re bound to get a wild 32-point-comeback once in a while, just as you’re bound to get a streak of 10 or 12 heads too. But just as the physical world cannot escape gravity, the statistical world cannot escape what’s called “regression to the mean.” Those wild streaks, as fun as they were, have very little bearing on what happens next.  


Stuart Sutton

Except that you have no "psychological" factor in coin flips. Its proven that "belief" in an outcome makes that outcome more likely from a human perspective... the athlete who "Believes" he or she will make the next shot is more likely to make that shot than the one who doubts their next shot will be successful. Thus a team of athletes who "Believe" in the outcome of a comeback pitted against a team who is scared they are going to "lose" as a result of the comeback creates a psychological scenario that can't be ignored and would define momentum..

MW

What you have here is a plausible mechanism for momentum. It is not clear how effectively the mechanism will work in real life, and hence the need for research.

There is a similar argument for anti-momentum: recent past success leads to overconfidence which leads to foolish risk taking which leads (most frequently) to loss.

If there were no plausible mechanism, we would be much less inclined to do the research, as there is little prospect of getting an interesting result for our effort. (If the topic is particularly attractive to us, as may be the case here, or if the implausible hypothesis is popularly held and is used to make important decisions, the research may be worth while anyhow. Homeopathy and vaccine-autism links are examples of where it is worth doing the research to get the obvious result, but this is getting way off topic.)

John

Surely this argument fails to take into account the fact that sport involves humans. A coin toss is a random event, a sporting sequence is not. If a team has pulled off a spectacular play three times, the fourth may well be "sprinkled with fairy dust" in that this team will be disproportionately confident of repeating the feat, while their opponent will be fearful of a repeat occurrence and possibly demoralised. I would have thought this would make a repeat far more likely, but please correct me if I'm wrong.

BenFletcherSports

I agree completely John

cubee

in basketball you definitely have something called "the zone"
i have experienced it myself a couple of times. you start playing a couple of levels higher than normal. everybody else on the court starts to become a prop for you to shine against. you make every shot you take. you actually feel them going in before they are released. how exactly you get in the zone was never clear to me but making a couple of good plays in succession was one kind of trigger. you feel your adrenalin level increase. it's as real being drunk.
so if a couple of players could be in the zone at the same time, then momentum would definitely become a factor.

Brent

There is a chapter, I believe in Gladwell's book Blink, about "the zone" -- where essentially you become so focused on the game that you become oblivious to outside distractions (ie crowd noise). In this phase, you're completely aware of all of your senses, which also helps you see small twitches in your opponents that you may not otherwise see. It's the same feeling you have when you're, say, in an automobile crash and everything seems to be moving in slow motion -- it seems that way because your senses are so tuned into what is happening right then. It is a very real feeling.

BenFletcherSports

This is the problem with so many scientists. They feel like they have to prove everything, and if they can't prove it then there's a good chance it doesn't exist. 'Momentum' is in our heads for sure, but that's exactly why it's so real. When football players allow 'momentum' to get into their heads, it becomes just as much of a mental game as a physical game. But you can't quantify that into data.

BenFletcherSports

www.BenFletcherSports.wordpress.com

Radiokev

I mean, this is kind of weak. A football game doesn't come down to momentum or chance. There's a tremendous amount of strategy, personnel decisions, and execution that go into it. A coin is hardly as dynamic as a human.

I don't think probability factors into all of our life outcomes, that's an awfully fatalistic view.

John

Looks like we're all singing from the same hymn sheet here. Freakonomics do some great stuff, and there's certainly a place for this sort of analysis in some areas of sport, but to extrapolate from a coin toss to a phenomenon inextricable from the nuances of human behaviour does seem misguided.

Sam Norton

As a former high school wide receiver, I have to say I disagree. In my experience, if a receiver makes one catch, the next catch becomes easier, and so on. I realize that this isn't exactly the same as momentum, but it's closely related. It's certainly psychological to a degree, but you could also argue that there is a learning process going on as well.

Erik Jensen

We can go with your selective memory of high school, or we can look at a large data set to see what actually happens. What is the completion percentage for quarterbacks who went 3/3 in the last three attempts? If your contention is correct, then we should MEASURE a detectable increase.

I always find it fascinating how impervious sports people are to evidence. When presented with data contrary to their preconceptions, they just say, "in my experience..."

Jen

Momentum isn't really about 4 great things in a row, either. Momentum isn't so much a thing that lasts for a long time as the ability to capitalize on a situation that arises in the short term which restores optimism.

That is, a pass getting intercepted, a fumble, a call that puts a long gain back and makes it a much harder third down situation -- those are the sorts of things that might switch the momentum of a game. A team that was behind is suddenly handed an opportunity. If that opportunity ends up resulting in a score, we say that the momentum has shifted -- the team that looked to be down and out is now scoring and the game is back in play.

That's not just one coin being flipped, it's about three or four or five different coins being flipped simultaneously all going on a heads streak at once. But then, I guess that's the point here? That we recognize and remember when something like that happens. Many times a bad (or good) call or a turnover don't cause a big change in the play -- and we don't think anything of it.

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Otto

I don't see why momentum explains "the Buffalo Bills’ redonkulous 32-point comeback against the Houston Oilers in 1993." If there were momentum, then wouldn't the Oilers just continue to build on their lead?

RGJ

Coins don't have lossed and bursts of confidence. Whoever wrote this hypothesis mustn't have engaged in competive athletic endeavors much. Or golf. Or darts.

Erik Jensen

The point of the article is not whether or not people gain or lose confidence in the course of a game. The point is that it might not matter to measurable performance.

JonE

I just don't believe momentum has THAT little to do with it. I agree that random chance can explain many streaks, but in games so heavily dependent upon a human element, the psychological factor has to be accounted for.

I haven't seen the data, but I would think that it's going off of te "average" as te benchmark, but I feel that is wrong. ANY DATA included there, hot streak, cold streaks, "normal"times are factored into that, so of course the hot streak will merely look like a statistical anomaly.

I guess my point is that it's easy to test when you have a "true average" to use as a benchmark--like 50/50 for heads and tails, but for a shooting percentage, this is not as obvious. Even if you use multi-year, time-series data, I think it's easy to underestimate the impact ending a season on a "high note" can have on confidence going into the next season.

Stuart Buck

Here's the thing: a 32-point comeback might indeed be so rare that it fits within a statistically normal distribution as several standard deviations above the mean. This does NOT mean, however, that a 32-point comeback was itself a matter of random chance -- the 32-point comeback happened because of how a bunch of human beings performed on a given day, and that had a lot to do with their preparation, their skill, and their confidence level (the latter of which would be affected if either team started to think that the "momentum" was heading in a particular direction).

Tom

I'm pretty sure the good people at freakonomics aren't naive enough to think there are no differences between a complex football game and a coin toss. I think the point they may be making is that more often than not we are mistaking a shift in a random sequence for a turnaround in momentum. I doubt anyone would argue that psychology never has anything to do with sports results but maybe it's effect is exagerated by fans and pundits.

Caleb b

Malcolm Gladwell's Blink discusses how increased adrenalin affects both vision and thinking speed. Police officers when firing shots can physically see bullets flying, have full thoughts in the matter of seconds, etc. The Zone is real and momentum is this zone. The distribution of the zone maybe perceived as random, but it is not the same as a coin flip.

Robert

I think the point of these studies is not to equate humans with coin tosses, but to show that the outcomes of all these human interactions are much the same AS IF someone was tossing a coin (suitably weighted for factors existing beforehand).

Mike

Exactly. I'm surprised how many commenters are missing this simple point.

Jack

I agree that some people are oversimplifying things here, but to say "tossing a coin (suitably weighted for factors existing beforehand)" is absurd. The very point of making an analogy to a coin toss in any comparison is that you are saying, "This is completely random and will therefore follow a normal distribution if tested ad infinitum." You are saying it is unbiased and unweighted. To qualify this by saying (suitable weighted for factors existing beforehand) renders the comparison redundant.

B-town

I think momentum can manifest itself in the way it affects your opponent psychologically, causing them to make bad decisions and play on "tilt".

But, I'm not sure if that qualifies as momentum or just poor discipline.

Kevin

Just wanted to point out that after "5 consecutive completions on a drive" the offense is going to be pretty close to the endzone. This is the easiest part of the field for a defense to defend. A lot less field with still 11 defenders means each defender's zone is much smaller etc. We would expect the probablity of a completed pass to be less here than the average percentage of a completed pass.

Part of statistics is "all things equal" and Dubner seems to have a real hard time seeing how one sequence of events can make the next event unequal to the average percents he quotes.

James Briggs

I don't think that Dubner is being honest. If he is right then statistics are useless because the knowing what happened in the past tells us nothing about the future. We ought to fire them all because they are useless.

James Briggs

Statisticians want everything to be random because that think it would confirm their importance. The problem is they don’t even understand their own argument. The basic meaning of momentum is that knowledge of the past can help us predict the future. If a team scores is it likely there is a reason that they scored? Wouldn’t that reason make them more likely to score in the future? One way to look at it is to ask if there is a reason to believe in the existence of skill. Moving from football to basketball are some people better at scoring in basketball than others. If I claim that a person is skilled at basketball because they make one hundred baskets in a row the denier of skill can say another person missed one hundred baskets in a row. But does that fact that someone missed a one hundred shots in a row support or negate my claim. A statistician could say if he flips enough coins some will come up heads one hundred times and in a row and some will come up tails one hundred times in a row. The problem is the statistician is seduced by the coins. He thinks if he twists events to look like coins then they are coins. Tim Tebow’s quarter back rating goes from 85 in the first quarter to 107 in the last quarter are we to believe that is pure luck? Tom Brady, converted 21 of 33 4th quarter comeback opportunities (64%) while Tom Rattly converted 1 of 11 opportunities for (9%). I would gladly bet that Tom Brady will make a 4th quarter comeback before a quarterback picked at random by a statistician.

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James Briggs

extinction

In the operant conditioning paradigm, extinction refers to the decline of an operant response when it is no longer reinforced in the presence of its discriminative stimulus. Extinction is observed after withholding of reinforcement for a previously reinforced behavior which decreases the future probability of that behavior.

If the players are not rewarded for making shots wouldn't extinction take place. Why not take streak player and reward them for making consecutive shots. See if that has any effect.

MAL

I would argue that momentum in football is very real and even quantifiable. Football game is not a series of unrelated events. Each play influences the next one. A string of positive plays increases a probability of the next play being positive due to a few factors:
1. It alters the game plan of the other team. Coaches come into games with a plan. They know which play to call in which situation and what players to put on the field. When things don't go as planned, they're forced to alter it. Let's say for example a quarterback gets sacked and hit a couple of times because a left tackle gets continuously beat by a linebacker. This forces the coach to pull out otherwise eligible receivers into blocking thus limiting the amount of offensive plays that can be called, which reduces a probability of a successful offensive play.
2. The crowd! The crowd in football plays a significant role in the outcome of the game. The crowd becomes louder if the home team continues making positive plays and it withdraws from the game if the away team gets on the roll. If you watch a football game you'll notice that the crowd gets louder when the home team is on defense and quieter when the home team is on offense. The reason for that is because the outcome of any offensive play often largely depends on the pre-snap adjustments which are made verbally. By making noise when the away team is lining up to snap the ball, the crowd impairs team's ability to communicate which causes more mistakes such as false start penalties, missed blocking assignments, incorrect routes ran by the receivers
3. The human factor. Athletes confidence, just like any other human being, depends on the amount of success. A wide receiver who just dropped a pass, may over-think the next catch going his way, whereas a guy who just made a spectacular catch will trust his instincts.

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James Briggs

Tebow, Broncos do it again, beat Vikings 35-32 - 11 minutes ago
Tim Tebow led yet another late rally, passing for a season-best 202 yards and two third-quarter touchdowns to help the Denver Broncos win their fifth straight game with a 35-32 victory over the Minnes...

There it is. We had a prediction and it came true. I think they are right about basketball shots but football is different. Its time for the anti-momentum people to put up or shut up.