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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

1 comment so far

Tags: baseball-reference.com, binomial distribution, Choke Index, Phillies, Ryan Howard, statistics

1 comment so far

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

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

or

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