We always hear how certain players are “models of consistency” or tend to “hit their home runs in bunches”, just to cite a few examples of when we talk about performance volatility. Today, Bill Petti of Fangraphs.com quantified this concept in a fascinating article pertaining to offensive performance.
Basically, Petti’s goal was to find out how players offensive performance (in terms of wOBA) is distributed throughout the season. His research answers questions like the following: Does player X tend to a few monster games, but often times is invisible? Does player Y perform poorly on a consistent basis? Keep in mind that being consistent does not mean a player is good.
I won’t get into the formula or the computation, but it factors a player’s standard deviation of daily wOBA and season wOBA. He abbreviates the result as VOL (for volatility, of course), and then indexes it using VOL- (100 being average). This study does not account for park factors, or hitter vs. pitcher parks.
Let’s take a look at how volatile the Yankees offense was. Before looking at the actual measures, let me lay out my intuitions on volatility, and see how accurate my eye test is. We’ll just look at those who received 300 PAs or more, since that was the qualification for making the study. That leaves us Derek Jeter, Robinson Cano, Curtis Granderson, Nick Swisher, Alex Rodriguez, Mark Teixeira, Russell Martin, Raul Ibanez, and Eric Chavez. I’m not including Ichiro because of the vastly different performances in New York and Seattle.
The Yankees I assume performed consistently daily in terms of wOBA: Jeter, Swisher, Rodriguez, and Martin. Jeter seems to always tack on one or two hits each game with minimal 0-fers; Swisher, from my memory, never had any monster games but got on base consistently; A-Rod was consistently mediocre or slightly above average; and Martin tended to be consistently poor offensively.
As for the rest, who I believe to be volatile. Cano’s torrent streak at the end of the year contributed to my belief that he tends to be incredibly hot or cold, Granderson because he’s a three outcome player (BB, K, or HR); Teixeira for the same reasons as Granderson; Ibanez because of streakiness; and Chavez because of his hot August and cool September.
So, how accurate were my completely unscientific predictions?
|Via of fangraphs.com|