What Exactly Do You Know?

Categories: General Info, Statistics
Comments: 1 Comment
Published on: October 14, 2014

(This post was inspired, in part, by a post Matt Waldman posted on his website a few days ago. If you haven’t already, go check out his site. He does an amazing job over there. The post in question is titled “Deny Emotion and You Only See a Fraction of the Game.”)

The establishment in sports has, for a while now, been telling outsider-sports-analytics types that one of the main barriers to widespread acceptance of analytics rests on the ability of the quants to communicate with the non-quants in ways that the non-quants can understand. I’ve covered the problems of communicating information both to quants and to non-quants in the past. But Matt’s post about emotion made me realize something more.

His general point was about the role emotion plays in sports performance. Specifically, he was contemplating whether or not momentum exists in sports. He cites conversations with analytics experts on the subject of momentum. If you’re familiar with the argument, most analytics experts conclude momentum does not exist. This is a fairly standard finding across many sports – basketball’s hot hand being another classic example. Matt’s reaction to that conclusion is also fairly standard among non-analysts. His argument is that emotion, and the effects of emotion on situations in sports are obviously occurring. Anyone who denies that is missing a huge portion of the signal inherent in the game. At one point he suggests that analysts have possibly never put themselves in physically dangerous situations and felt the impact of emotion first hand.

So, two things with that summation, both having to do with communication. First, assuming experiences that someone has or hasn’t had is a raw nerve for me. The stereotype of the milquetoast academic who simulates experiences rather than having actual experiences looms large over me. I’m guessing it has something to do with my father telling me to put down the video games and go spend some time working on my grandfather’s farm. But, I know the comment wasn’t directed at me and it wasn’t malicious anyway, so let’s put aside any irritation that might shut our brains off. In fact, we need to keep our brains on if we’re going to truly examine the point Matt is trying to get at.

Analysts (myself included) are often guilty of a particular linguistic shorthand. Our job is to find predictive effects. Does changing the way a request is phrased reliably change donations to charity? If I know about your height, can I make an educated guess about your weight? That sort of thing. We can become so familiar, so practiced in that job that, when we talk to other people, we tend to shorten the description of what we’re talking about. When my neighbor asks me what I know about momentum in sports, I say “I’m trying to find out if momentum exists” and he gets excited and engages with the conversation. The problem for analysts, though, is that this gets the conversation off on a disingenuous foot. Because we’re not truly trying to find out if momentum exists. We’re trying to find out if the predictive effect of momentum on some other variable, like scoring, exists. But we repeat the phrasing about studying the existence of momentum so much that we can forget that other people see that collection of words as having a different meaning.

And when we analyze the results in sports, the results a pretty clear. The effect of momentum on any variable we look at is unpredictable. The same is true in the academic literature as well. We cannot predict the effect of emotion on motivation with any reliability. So, I agree that we should probably stop saying that momentum doesn’t exist. The subjective experience of the emotion of the game is a real thing that people feel.  But I will hold fast to the notion that predicting what will initiate a change in momentum and how a change in momentum will impact athletic performance is an unpredictable enterprise.

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  1. […] In last week’s post, I discussed the concept of what statistical inference actually tells you and how it’s boring and cumbersome to talk about it accurately, so analysts often shorten the conversation so they can actually talk with real people about something interesting. Today we take a slightly different tack regarding what exactly we know. Our example for this week is Minnesota Vikings quarterback Christian Ponder. […]

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