Why Batting Average Fails, and Two Stats You Can Move On To

Not the best batting average, but #2 OBP and #1 in wOBA.

I am not a professor of baseball. I am not an expert of baseball. I have not been a nerd-baseball-head for years upon years, but we live in a culture where when you think about someone’s batting stats, batting average is probably one of the first things you think of. Most fantasy baseball leagues encourage this as well in your basic 5×5 categories that have R, HR, RBI, SB and AVG and that probably drives the idea deeper that batting average is important. Well, it might be in winning your league, however since those Sabermetrics (and please remember Billy Beane did not write Moneyball) have come about, the times have changed. I’d be willing to say even as recent as last year, I still bought into batting averages, but I read what people had to say and saw baseball experts make fun of and put down others that suggested those were reliable measures to evaluate a hitter.

That's all that happens at the plate, right?

When I look at statistics now I try to ask myself, “What does this category accomplish? What is it evaluating?” and with batting average you ask yourself the same thing. What does a “batting average” evaluate? In mathematical terms, it’s just hits divided by at-bats. It’s a very simple statistic and I can see why people like it. Easy math. Keep in mind though that plate appearances can also be counted as walks, intentional walks, hit-by-pitches, or sacrifice bunts and flies. So already we’ve established that batting average is missing something in terms of what a player can possibly contribute. If baseball were an easy game, players would have batting averages in the .800s and .900s and pitchers would probably be paid the league minimum on every team. But baseball is not an easy sport. There are times when it takes a little luck to hit that ball and have it drop 5 feet in front of the LF, or for it to just sneak under the glove of the 1B who happens to have one of the best defensive-zone ratings in the league. But I digress. My goal with those statements is to make you believe that batting average is not the best evaluation of a hitter. If you haven’t been introduced to them already, let me introduce you to 2 offensive stats I like to look at that aren’t too nerdy.

You can read the Fangraphs article about OBP here as it tells you the same thing (or probably better) than how I’m going to talk about it. I didn’t even tell you what OBP is though, and it is “On Base Percentage,” simply put: how often did the player reach base — whether 1st, 2nd, 3rd or home? As you can see with the formula, it has hits, walks (both unintentional and intentional) and hit by pitches over ABs, walks, and sacrifices (because you don’t reach base with a sacrifice). Most of the time the goal of baseball is what but to get on base. I don’t care who you are but if you liked someone like Starlin Castro for example in 2011 who has a batting average of .307 better than Troy Tulowitzki because Tulo hit only .302, you’re crazy because Starlin’s OBP is .341 while Tulo’s is .372 in 2011 (and for other reasons, too, in my opinion). Or Melky Cabrera (.305/.339) vs. Lance Berkman (.301/.412) in 2011. As for how to measure a “good” OBP and whatevers, I’m going to include this graphic from Fangraphs to help out… mostly because I chuckle when I see a certain name:

Yea. Aubrey Huff did that in 2010. And since 2012 is an even year and he’s doing crazy pilates, we can expect that again in 2012. But anyway, that was OBP. Like it? Of course you do. Let me introduce you to my 2nd stat I like: wOBA. (I do like a lot of other stats though!)

While you may be unsure how to pronounce “wOBA,” it stands for “weighted On Base Average.” Why is this stat important to me? Well, it certainly isn’t because of the mathematical formula that’s used to calculate it:

The wOBA formula

Now, how Tom Tango explains it in his math language here I could never do on my own so if you want to dive more into it there, or at your friendly Fangraphs site (but not by Tom Tango) by all means go for it. But here’s what wOBA does: it recognizes that not all methods of reaching base are created equal. While SLG% or “slugging percentage” as you might have heard about makes an effort to do this, it basically is saying that doubles are worth twice as much as singles, triples 3x as much, and so on as you’ll see here in the formula to calculate slugging percentage…

…when it really is hard to say that that is the case. You also get into trouble when you start considering not every ballpark athletes play in are the same and that opens a whole ‘nother avenue to another statistic. So Tango used that wOBA formula above and had to tinker with the coefficients a bit before he got it to have the numbers line with the OBP numbers. Why not the batting average numbers? I don’t know the answer but I’m going to assume he probably didn’t want to encourage batting average as a reference to evaluate a player. wOBA takes an impact at what the player does at the plate (including walks) and does a better job of it than SLG%, in my opinion.

So while this was a bit lengthy, I hope that if you came in reading thinking batting averages were good, or you didn’t know other ways to evaluate a player offensively, you have a couple new tools in your pocket. I hope I’ve opened up the door for more learning and I also hope this wasn’t dreadfully boring.


Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s