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"Uncertain Principles" features the miscellaneous ramblings of a physicist at a small liberal arts college. Physics, politics, pop culture, and occasional conversations with his dog.

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Chad Orzel "Prof. Orzel gives the impression of an everyday guy who just happens to have a vast but hidden knowledge of physics." (anonymous student evaluation comment)

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« Social Networks Do the Darnedest Things | Main | links for 2007-11-15 »

The Teammate Desirability Factor

Category: BasketballBlogsSilliness
Posted on: November 14, 2007 10:24 PM, by Chad Orzel

Over at the World's Fair, Dave is asking people for their scientific eponyms, that is, the formula they would like to have named after themselves. These are, of course, entirely made up.

Here's my contribution, from the scientific study of pick-up basketball: the Orzel Teammate Desirability Factor (TDF):

formula.gif

The Factor ranges between positive and negative infinity and is a quantitative measure of how much I want to have a given player on my team. The components going into this are:

  • P is the average number of points scored per game
  • ρ is the player's career shooting percentage
  • A is the average number of assists per game
  • S is the average number of steals per game
  • R is the average number of rebounds per game
  • T is the average number of turnovers per game
  • Y is the Yap Measure, the amount of time the player spends talking during a given game
  • K is the Knowledge Factor, which measures the player's knowledge of the game of basketball.

The Teammate Desirability Factor consists of three terms:

1) The product of points per game and shooting percentage. If you score a lot of points, that increases my chances of winning, which is a positive factor. If, however, you take fifty shots a game to score five baskets, you're going to get on my nerves, so the scoring needs to be weighted down by the shooting percentage.

2) The product of assists, steals, and rebounds divided by turnovers. Obviously, assists are good, because that means you're likely to pass the ball to me in scoring position. Steals are a reasonable measure of defensive ability, and defense wins championships. Rebounds get us extra posessions, which means more chances for me to score.

Turnovers, on the other hand, are bad, and offset the positive effects of steals, assists, and rebounds.

3) The Yap to Knowledge Ratio. Trash-talking during the game is a negative factor, but is mitigated by general knowledge of the game. It's OK to talk smack if you know what you're talking about.

If however, you are a know-nothing pinhead with a big mouth, this ratio becomes extremely large and negative, indicating that you are not the sort of player I want on my team, because you're just going to piss me off.

As you can see from the formula, the best teammates are players who score well on efficient shooting, play defense, pass, and rebound without turning the ball over too much, and keep their mouth shut unless they have something useful to say. Such players are, sadly, rather rare.

Steals and rebounding can offset a poor assist-to-turnover ratio, provided there are at least some assists (if any of those factors are zero, the second term cancels completely). Some theorists suggest that the first term should be modified to reward "clutch" shots-- the so-called "Baum Criterion"-- but it is not clear that the net effect of the occasional game-winning bomb compensates for bricklaying during the main action. Some researchers argue for increasing the importance of steals (the Mahmood-Rice Conjecture), while others argue that steals obtained by deceptively calling for the outlet pass shouldn't count (the Bartell Correction).

Note that the only real way to end up with a negative TDF is through yapping without knowledge. Turnovers and poor shooting can reduce a player's TDF, but not send it into the negative range. Again, there are competing theories that reduce the negative impact of yapping provided that the trash-talking is amusing. This is the known as the Lanterman-Bodden Effect, but further experimental study is required to determine the magnitude of the effect.

Comments

That would make an interesting t-shirt.

Posted by: Brian | November 15, 2007 12:18 AM

hmmm... interesting analysis, but not the way I would have constructed the formula.

You point about the second term becoming 0 with relative ease is, I believe, too important to leave as-is. A short guy who's quick and passes a lot? Shouldn't get a goose egg for that term. Maybe [(1+A)(1+S)(1+R)]/T if you want to keep those criteria together.

Also, for static teams (this to me implies that you are playing something bigger than 2v2 and you have more guys on the team than you can field at any given moment) your last term will leave out some very desirable players. As it stands one cannot gain any desirability from knowledgability. Understanding the game only serves to mitigate one's yappiness factor. The more people on the team and the more serious the stakes (beer league 5 on 5 vs. pickup 2 on 2), the more important it is to have one guy who understands what's going on and can act as a "coach" type figure.

Good start though!

Posted by: Isaac | November 15, 2007 4:08 AM

Seems as if turnovers are calculated in disproportionately. According to the equation, someone who NEVER turns the ball over is infinitely useful even if there are no other positive factors at all.

Posted by: Kevin W. Parker | November 15, 2007 6:02 AM

Isaac: You point about the second term becoming 0 with relative ease is, I believe, too important to leave as-is. A short guy who's quick and passes a lot? Shouldn't get a goose egg for that term. Maybe [(1+A)(1+S)(1+R)]/T if you want to keep those criteria together.

That's a good suggestion.
In practice, those numbers are essentially never zero-- even the biggest gunner sometimes passes the ball. But adding some constant factor to each might improve the results.

Also, for static teams (this to me implies that you are playing something bigger than 2v2 and you have more guys on the team than you can field at any given moment) your last term will leave out some very desirable players. As it stands one cannot gain any desirability from knowledgability. Understanding the game only serves to mitigate one's yappiness factor. The more people on the team and the more serious the stakes (beer league 5 on 5 vs. pickup 2 on 2), the more important it is to have one guy who understands what's going on and can act as a "coach" type figure.

This is intended to refer to pick-up games, where coaching from the sidelines isn't relevant. Knowledge on the court isn't directly a positive factor, but it does indirectly contribute-- a player who knows the game well is more likely to score points, deal out assists, and get steals.

Knowledge is a positive factor insofar as it leads to increased productivity. Knowledge in the absence of game is not helpful.

Kevin Parker: Seems as if turnovers are calculated in disproportionately. According to the equation, someone who NEVER turns the ball over is infinitely useful even if there are no other positive factors at all.

This would be an argument for leaving out the constant offset suggest by Isaac-- if they have zero assists, zero steals, and zero rebounds, that would remove the zero-turnover singularity. Of course, it'd probably be nice not to need calculus to figure out a player's rating...

Alternatively, we could add a small positive offset to the turnovers, too.

Posted by: Chad Orzel | November 15, 2007 8:34 AM

what number does Stephon Marbury get?????

Posted by: perry | November 15, 2007 11:49 AM

According to these stats, Marbury averages 19.8 points with a shooting percentage of 0.412, so the first term comes to 8.15. He has 3.0 rebounds per game, 7.9 assists, and 1.2 steals, divided by 3.1 turnovers, so the second term is 9.17.

We can estimate his Knowledge Factor to be about 0.1, based on his demanding a trade away from Kevin Garnett, and he has a Yap Measure of about a million.

So, the final Q_tdf = 8.15 + 9.17 -10,000,000.

HTH. HAND.

Posted by: Chad Orzel | November 15, 2007 11:57 AM

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