Hello everyone, and welcome to the first edition of Stat Head. Each week, I’ll be breaking down a different statistic. Normally, this will be a statistic that is a little unconventional, one you probably wouldn’t be hearing about on, say, an ESPN.

First, a little about myself. My name is Derek Carty. I am a student in New Jersey and an avid fantasy baseball player. I am the chief fantasy analyst for the Hardball Times, where I write for the Fantasy Focus blog. If you like the types of things I delve into here, feel free to stop by the Hardball Times, where I apply these concepts to actual players.

I won’t be talking about a specific stat today, but rather why the stats I will talk about in the future are important and how they can help you win your fantasy baseball league.

The heart of baseball statistics comes down to this: baseball is game part skill, part luck. For each of the 10 primary fantasy stats, there is some measure of luck involved. Simply by looking at one of these stats, one cannot tell if it is truly reflective of a player’s skill. In fact, for each of these stats, you can better predict them from year-to-year using some measure other than the stat itself than you could by using the actual stat. Pitching strikeouts can predict themselves quite well, but even for these there are other – perhaps better – ways of forecasting.

If up until now you have been unfamiliar with this concept, you may be asking yourself, “So how do we predict the stats, if they can’t predict themselves? How is that even possible?” The answer, at the barebones, is to separate the luck from the skill. If we look at the components of each stat separately, at the things a player can control (or at the things he can’t), we can see where the expected level of the stat should be. By doing this, we can better predict the path that the stat will take in the future.

If you’re still not convinced, look up the stats of your favorite pitcher. It really doesn’t matter who it is. Just make sure to pick someone who has been in the majors for at least three years or who you have minor league numbers for. Do that now… I’ll wait for you.

Now look down the column labeled “ERA.” Notice how ERA fluctuates from year-to-year, seemingly without any rhyme or reason. Take Johan Santana who is pretty much the consensus top pitcher in baseball. In the past four years, his ERA has ranged from 2.61 to 3.33. While obviously good, if you were to try and put Santana on an ERA for 2008 by only using that information, it might be a little difficult, no?

You might think that the difference between putting him at a 2.60 ERA or a 3.30 ERA is negligible; I mean, they are both great figures, ones you would surely take on your fantasy team any day. The truth, though, is that there is a 0.70 difference between the two. That is a huge gap. That’s nearly a full ERA point.

Once you move away from the elite pitchers, that 0.70 could be the difference between a pretty good 4.00 ERA and a pretty poor 4.70 ERA. In many fantasy leagues, that is the difference between a #3 fantasy pitcher and one who isn’t rosterable. And the killer part is that there is just no way to tell whether it will be on the high end or the low end if you only focus on ERA. It seems a little counterintuitive at first, but you need to dig deeper than the stat itself.

That’s where I come in. I’ll tell you the stats you should be looking at, the stats that dictate where a player’s ERA (or any other stat for that matter) should end up. Because there is luck involved, it will be impossible to always get it right, but in the long run you will get far more right than you would by any other means, and that’s really what it’s all about.

Baseball is not about perfection. In conventional terms, a player who hits .300 is considered a success, completely ignorant of the fact that he failed to get a hit 70% of the time. If we look at a little bit more complete statistic and an absolute freak like Barry Bonds, we see an OBP that was once an absurd .609. Still, failure occurs 40% of the time. If one consistently gets just 60% of the questions on a high school or college exam correct, that person would not graduate.

Baseball is not about perfection, and predicting baseball statistics is the exact same way. Perfection is not an option because of the high variability of the stats… because of the luck factor. But by digging deeper into the stats, we can begin to sift through the luck, find the skill, and from there we can make better predictions than we ever could before.

That’s all for now, but be sure to stop by on Tuesday as I begin to discuss some of these statistics, starting with the one I like (and hate) the most: Batting Average on Balls in Play (BABIP).