Following his team’s loss to Turkey in the final game of their group stage, the US soccer team’s manager Mauricio Pochettino complained about the use of the word ‘momentum’ in sports.
“[Momentum] is a topic that I don’t understand,” Pochettino said when asked about how the loss would affect his team’s prospects. “What is momentum? To play with the same team that we played against Australia? And to take the risk to receive a yellow card and not to play the next game? Did Germany lose the momentum too [in their 2-1 loss to Ecuador]? I don’t know. [There are] too many topics in soccer that I don’t understand. The objective was to finish first, and we are first, and now is the next stage, and it’s going to be a final, and we are ready.”
Pochettino has a point. There is no doubt that a team is happy when they win and sad or disappointed when they lose. But ‘momentum’ is one of those words that have a scientific sheen and used to give weight to the idea that there are ‘hot streaks’ and ‘cold streaks’ in sports, that a win will likely increase the chances of a win next time and a loss will lead to more losses. But one result is not a trend, though the word ‘momentum’ seems to suggest that it can be.
But the broader question is whether there such things as streaks at all. One can point to streaks after the fact but are they predictive of the future? For a long time, it was thought that this was an illusion held by players and fans alike, and led to the idea that people are irrational, having beliefs and making decisions that lack statistical support. The illusion hypothesis found support in a study of basketball.
Thomas Gilovich, a graduate student in the early 1980s, began comparing the widespread perception of hot streaks in basketball to the hard data. Gilovich, now at Cornell, led a study showing that the hot hand didn’t really exist: The shooting records of the Philadelphia 76ers provided no predictive value of subsequent shots. A player might be hot one minute, but not the next. Fans and even sports professionals, they concluded, were making decisions based on myopic impressions.
But others said that that analysis was flawed. Another study by Jeffrey Zwiebel and Brett Green says that basketball may not be the best sport to study this question, and that baseball may be better.
Zwiebel and Green argue that the original finding failed to account for a key issue. In basketball, the opposing team quickly adjusts to a “hot” player, devoting extra coverage and forcing that player to attempt more difficult shots. As a result, it’s inevitable that a hot player’s shooting percentage will decline. It’s not because the hot streak was an illusion, but rather that the hot player attracted more opposition.
Baseball is different, because pitchers and coaches have very limited ability to re-deploy resources against a hitter on a hot streak. Pitchers and coaches do play to a hitter’s particular weaknesses, but they can’t put more people in the hitter’s way.
A more sophisticated analysis of basketball statistics found that streaks existed even in that sport.
As it happens, a team of Harvard researchers reached a similar conclusion in a new study of basketball. The Harvard team looked at data on 83,000 shots made during the National Basketball Association’s 2012-2013 season. But instead of looking simply at completion rates, the researchers built a model for gauging the difficulty of shots. They found that players who had exceeded their expectations in recent shots were likely to face tighter opposition and take more difficult shots. Adjusting for the increased difficulty of the shots, the researchers found that hot players were likely to continue outperforming. The “hot-hand effect,” they estimated, raised their chances of making a shot by 1.2% to 2.4%.
Interestingly, the people who study these questions tend to be in business schools because they are very interested in how beliefs drive actions in the marketplace, because those influence what remedies are taken, such as after the financial crisis of 2008 triggered by sub-prime mortgages.
Investment bankers have been criticized for underestimating the risks of subprime mortgages, for being irrational in their optimism. But it’s possible that their excessive risk-taking wasn’t irrational as much as it was encouraged or even subsidized by regulatory policies, such as those that protected banks considered “too big to fail.” The difference between those two diagnoses of the financial crisis leads to very different proposals for reform.
“One can portray the financial crisis as being triggered by a bunch of mistakes, or one can portray it as the consequence of risky decisions that were made based on the incentives and subsidies in the system,” he says. “I see it as more of the latter.”
People tend to extrapolate into the future from current events. This is especially true in politics and the stock market where pundits make a living by reading the tea leaves and predicting what will happen next. In politics right now, progressives seem to be on a bit of a roll in the Democratic party while the Trumpers are on a streak in the Republican Party. But all it would take is for one or two reversals for the pundits to all claim that the opposite in the trend.
anything involving human ability will naturally have streaks because that’s how human health works. we have an equilibrium based on our current diet, exercise, etc, and that can continue for a while until disrupted -- and those disruptions can run to weeks or longer, again, a streak.
The coach knows what momentum is. He’s just downplaying the loss. He knows it would have been better if they won but he doesn’t want the team to lose confidence.
“Interestingly, the people who study these questions tend to be in business schools…”
That’s a problem. They should talk to actual athletes. As a former athlete (mediocre at best), athletes go through hot and cold streaks much like Bébé Mélange said.
Also, a player can be on a hot streak and the team loses and vice versa.
One measured parameter in football is “possession” of the ball. If that is important, scoring a goal is a bad move, because it ends the possession streak.
As a rule, statistical analyses of sport are just technobabble, used to keep up the image of being an expert in the game.
We can reduce this to basically two questions:
Firstly, does a player’s psychology affect their performance? Do they play better when they are feeling confident, for example? This will obviously vary a great deal between individuals and across different sports, but I think you’d be hard pressed to find anybody who answers that question with a hard “no” except in games of pure chance.
Secondly, does success or failure affect a players psychology? Again, this will obviously vary a great deal between individuals, but again, I think basically everybody would agree that it does to at least some extent.
So, if psychology affects performance, and performance affects psychology, how could streaks not exist?
The question of whether you can reliably identify an individual streak as it is happening is a rather different one, which is going to depend almost entirely on how much statistical noise there is -- in the vast majority of cases, I would expect the data to be far too noisy to identify any specific streak with much confidence. This is rather like how population-level statistics let us be very, very confident that exposure to air pollution leads to various health issues, but it’s much harder to reliably attribute any specific individual’s health issues to their exposure to air pollution.
Still, there are some sports where I think you probably can… If you watch professional snooker, for example, you can pretty easily tell who’s feeling good and who’s feeling bad, and you can often pinpoint the exact moment when somebody turns from one to the other. It’s not that unusual for somebody to play well for a number of frames, then make one critical mistake and fall apart for the rest of the match -- and much more so for some players than others. For example, Ronnie O’Sullivan is widely regarded as the most talented player of all time, but he’s also notoriously one of the most temperamental, whereas Steve Davis was famed for his poise and reliability.
It seem a little awkward that even adding some weight/interpretation to the results the outcome is under 3%. That sounds like a rounding error or an artifact of how the measurement is done more than significant proof. And from the way the other study is mentioned it sounds like that’s exactly what it is, something entirely dependent upon the way the results are viewed, a difference that disappears with a different perspective.
This does not mean these streaks don’t exist or that the chosen perspective isn’t a correct method to identify them. But I think it does raise reasonable questions about why they’re so insignificant even when found.
Personally I am not into sports so I have a very outside perspective when I hear someone go on about what has happened in a sport. It really honestly sounds to me like the announcers are just dumping statistics and making up stories with them. I play roleplaying games with groups of my friends so I’m very familiar with the concepts behind cooperatively building a story together, particularly with one person largely directing the story. So while a reasonable criticism might ask if I’m seeing that pattern where it doesn’t exist, I do feel like it does with talk around sports.
A lot of American sports in particular have lengthy times between plays when compared to how long the actual action is happening. This creates a lot of empty time for sports announcers to fill and they seem to do it by crafting a story about how the various plays and different games come together to spin a single narrative. That’s just what the audience wants to hear. It’s more interesting than viewing each play in isolation.