"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.

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.