Quickie: Ryan Howard’s Choke Index

Quickie: Ryan Howard’s Choke Index October 25, 2010

Posted by tomflesher in Baseball.
Tags: baseball-reference.com, binomial distribution, Choke Index, Phillies, Ryan Howard, statistics
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The Choke Index is alive and well.

Previous to 2010, Ryan Howard of the Philadelphia Phillies hit home runs in three consecutive postseasons. He managed 7 in his 140 plate appearances, averaging out to .05 home runs per plate appearance. Not too shabby. It’s a bit below his regular season rate of about .067, but there are a bunch of things that could account for that.

This year, Ryan made 38 plate appearances and hit a grand total of 0 home runs in the postseason. What’s the likelihood of that happening? I use the Choke Index (one minus the probability of hitting 0 home runs in a given number of plate appearances) to measure that. As always, the closer a player gets to 1, the more unlikely his homer-free streak is.

The binomial probability can be calculated using the formula

$f(k;n,p) = \Pr(K = k) = {n\choose k}p^k(1-p)^{n-k}$

Or, since we’re looking for the probability of an event NOT occurring,

$(1-p)^k$

or $.95^{38}= .142$

using his career postseason numbers. That means that Ryan Howard’s 2010 postseason Choke Index is .858. Pretty impressive!

Comments»

1. Ed Foster - October 26, 2010: The world has figured this guy out. Aside from a novelty act press pass on the Eagles sidelines, the next kudo he receives will be….. forget it, he’ll never get another award. He’s the 2nd highest paid player in MLB and probably about the 15th best player. I blame Amaro. The guy has acheived only when his next payday is in doubt. Yet, Amaro rewards him in midseason, P.O.’s Werth and removes all incentive for any improvement. Move hin now. His value will never be higher. I quote: “I had my stroke for 31 homers and 108 RBI’s, didn’t I”? Hand Utley a first baseman’s mitt and get on with the retrenching.

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