This is a lazy post. I apologize in advance for that. But it’s New Year’s Eve and no one wants to read a lot of words on New Year’s Eve. So I’ll skip the words part (mostly) and just show you some numbers.
A while back, sabermagician Tom Tango helped to develop a neat little metric called kwERA. I call this metric “neat” both because of its slang meaning, that being “wonderful and terrific”, and its literal meaning, that being “orderly and clean”.
The reason kwERA is “orderly and clean” is that it only takes three variables as input: strikeouts, walks, and plate appearances. Specifically, the formula for kwERA is as follows:
kwERA = 5.40 – (12*((K-BB)/PA)))
It’s really that simple. Just subtract walks from strikeouts, divide by plate appearances, and adjust it to a similar scale as ERA. Neat, huh?
kwERA is neat in the sense that it is “wonderful and terrific” because it is remarkably good at predicting future performance. It’s as good or better than virtually all the ERA estimators out there, and does so simply by looking at strikeouts and walks. That’s pretty neat if you ask me.
Ok, I said I wouldn’t write too many words today, so without further ado, here’s the kwERA for the four main Yankees starters in 2012:
As you can see, the kwERA numbers are fairly encouraging for the four Yankees starters (Andy Pettitte didn’t log many innings, so his kwERA wouldn’t be very helpful for predictive power). Hiroki Kuroda is the only one of the bunch who doesn’t look so good when just considering strikeouts and walks, but the other three, especially Ivan Nova, are all in line for improvement come 2013.
Of the four, Phil Hughes is actually the most encouraging for me. The home run ball has always been his problem, so removing it from the equation is obviously going to help him a lot. I’ve always been a bit pessimistic about Hughes, but this gives me reason for optimism. He’s only 26 years old, and if he can limit the home runs and get his ERA closer to his kwERA, the Yankees could have a very strong rotation in 2013.
Credit to Tom Tango, GuyM, Glenn DuPaul, and Fangraphs for the data and research.