FanShot

The Carry of a Fly Ball

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There was much discussion in the early weeks of the 2009 MLB season about the large number of home runs hit in the new Yankee Stadium, leading to speculation that many of the home runs were aided by strong wind currents. Or, in the lingo of baseball, the ball was "carrying well" in Yankee Stadium. All this discussion stimulated me to ask the question, "Just what is meant by 'carrying well'?" Of course, we all have an intuitive notion of what this means. We observe a fly ball coming off the bat and have an expectation of how far the ball will travel. If the ball traveled farther than this expectation, we say that the ball carried well. And of course, vice versa. But can we come up with a more precise, less intuitive measure of "carry"? It is precisely this issue that led to the analysis presented in this report.