Anchored in Spring

We can rationally tell ourselves that small sample sizes have to be taken with caution (and they do), but no matter how much we believe that to be true, they will still affect us. It’s a byproduct of a psychological bias known as anchoring and for the most part it’s extremely difficult to avoid falling victim to. The aspect of anchoring (or focalism as it’s also known) that we must be aware of for baseball purposes is sometimes referred to as the adjustment problem. In a nutshell, the adjustment problem is when you are asked to make a value judgment on something. Almost without fail, your brain will go back to some previously heard value and adjust from there. Basically, it’s letting an extremely (and sometimes completely irrelevant) small sample hold a sway over your perception and it’s tough to avoid.

What I am specifically getting at is performances in April and how they influence opinions of players for the rest of the year. A hot start in April establishes a baselines of performance at a high level and probably gets mentioned a lot in the media. From that point forward, no matter how well that player performs, unless you are intimately familiar with the player’s performance, your first instinct is to go back to those numbers you were hearing about in April and adjust from there. This is similarly true for cold starts. All that’s needed is for the performance to be extreme enough to get mentioned and for you to not pay that much attention to the player at other times. Need a few examples?

These aren’t going to apply for everyone, we don’t all have the same strength of bias and like I mentioned above, if you happen to follow a player day to day whether because he’s on your favorite team or rival team or fantasy team or whatever then you will not be as susceptible to the adjustment because your brain has many more data points stored away. The key is not having heard or seen a player’s stat line for awhile. For American League fans, quick, how has Miguel Tejada and Carlos Delgado‘s season gone? Think of their line in your head right now. Now go click on those links and see how you did?

Most of you, if you qualify above, would have over-estimated Miguel Tejada’s line and under-estimated Carlos Delgado‘s. Tejada got off to a fast start in Houston and made some news as they flirted with contention and since Tejada had come over via trade and posted a near 1.000 OPS in April. But since May 4th, Tejada has posted just a .263/.295/.367 line. Delgado has been the opposite. He sat at a meager .532 OPS on April 27th and was subject to some stories about how the hope for a bounce back from his previous year’s struggles were not to be. All Delgado has done since then is hit .274/.360/.542 and he’s now up to a .840 OPS on the year and making a case for his option to be picked up by the Mets.

A last one, this time for the National League folks. How’s Jacoby Ellsbury doing? He was in the news a lot this spring for his fast start to the year paired with the Red Sox defending title and his memorable October. Through Ellsbury’s first 28 games this season he had an .857 OPS and an impressive 17 walks to just nine strikeouts. But since then, Ellsbury is hitting just .258/.304/.347 with 66 strikeouts to just 22 walks and his season OPS is now under .700.

Beware those early numbers.

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Matthew Carruth is a software engineer who has been fascinated with baseball statistics since age five. When not dissecting baseball, he is watching hockey or playing soccer.

2 Responses to “Anchored in Spring”

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  1. Greg says:

    I have to think the average reader on this site does not fall prey to this kind of bias very often, although I don’t disagree that it’s something to be aware of, especially when you hear baseball players discussed in the media. In fact, I think I’m especially well aware of how much Delgado has turned it around in the past several months because of a slow start.

    Using that example, I think we tend to forget that Delgado’s season line, which is certainly impressive, is now back in line with what we would expect from him. Because everyone left him for dead in April and May, it now seems remarkable that he’s putting up an .840 OPS on the year. However, that’s about where he was likely projected (I’m guessing) for this year.

    Meanwhile, because Ellsbury had such a fast start, it’s not that baseball fans assume he is still doing well. Instead, we built up high expectations for his ’08 and as such are more liable to be disappointed with the results, quickly forgetting that this is his first full year in the majors and struggles were inevitable.

    I think you make a valid point in this article, but you argue it from the wrong direction.

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  2. Bill Krevski says:

    I think its almost impossible not to fall victim to small sample sizes at times because almost every media outlet in some form or fashion pushes them on you. Whether its team streaks or what a player is batting over the last week or series or vs this pitcher, its hard to block all of that out, knowing that it’s highly arbitrary and selective and ultimately doesn’t accurately portray the real picture.

    This easily can be applied to fantasy baseball, when you are deciding which of two players to play for a particular game or week etc., you often use small meaningless sample sizes to convince yourself that one is the better option then the other, when in reality you can find small sample size numbers to support choosing either player and it simply comes downs to which one you “wanted” to play the entire time.

    All this being said, if you do your best to avoid the ups and downs of variance within a season and just look at the final outcomes, you’ll be suprised how many were comfortably in the range of what you would have predicted before the season began, yet if you evaluate these same predictions during the season you will have a tendency to doubt yourself and your judgments based on these trvivial sample sizes that are merely traps setup to fool your mind.

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