Why OBP is so Important

So after re-reading my last post, I realized that I relied a lot OBP as a statistic, but I didn't really give non-stat heads a good explanations of what that number means, why it's so important, and why it helped make my point so artfully and eloquently.

And since I'll be using OBP a lot on this site, I figured I'd write something up to be clear and get everyone up to speed.

What it Means

OBP stands for On-Base Percentage and it works kind of like batting average does. Instead of just counting hits, however, it counts anytime you reach base, whether it's by getting a hit, drawing a walk, or getting hit by a pitch.

You also count walks, hit by pitches, and sacrifices in your at bats, which you normally don't do to calculate batting average.



What it Tells You

If batting average tells you how good a hitter is at getting hits, then OBP tells you how good a hitter is at getting on base.

Why It's So Important

Sounds like a pretty puny stat, doesn't it? Well, that's because the definition doesn't tell you everything you need to know.

A hitter with a higher OBP draws more walks. A hitter that draws more walks has certain valuable qualities that tend to make him a better hitter:

1. Patience: Not afraid to see a pitch or two or go deep into the count. Some guys hate getting into two-strike counts for fear of striking out (Corey Patterson must live in a world of fear), but if you're patient you don't mind it at all. It means you see more pitches and work the count more, which leads to...
2. Selectivity: Selectivity means a player will mostly swing at pitches he can effectively hit (Vladimir Guerrero's piñata swing falls into the "anti-selectivity" category). This is good because it maximizes the odds of making solid contact and doing something good with the ball. Fastball down the middle? Hammer it.
   
3. Control of the strike zone: This one relates to #2 and #1. Control of the strike zone means you know what's a strike and what isn't. It means you're more likely to let pitcher's pitches that are balls go by and not let strikes go by if they might be strike three. Nasty cutter inside? Let it go.

What Makes a Good OBP?

A .300 average is generally equated with good hitters. OBP has its own bar, only there are two of them because OBP on its own matters less than it does compared to a player's AVG:

1. A .400 OBP generally means you have a hitter that's really good at drawing walks.



2. If a hitter has a +100-point differential between his average and his OBP, that's also a very good sign. So if a guy hits .260 and has a .360 OBP that's an indicator that he's got a pretty good eye. If a hitter has a .240 AVG and a .380 OBP it means he's a pretty lame hitter but has outstanding patience, selectivity, and control of the strike zone.

Adam Dunn and Jack Cust are good examples of OK hitters with really good OBP differentials:



The interesting thing is that you rarely see players with a bad average and a high OBP. Why? Because if you have the qualities to draw a lot of walks, they will help make you a better hitter and in theory you won't be hitting .260.

And that's why OBP is such a powerful number—it tells you what a hitter has done statistically but it also shows you how patient he is, how selective he is, and the type of approach he has at the plate.

That one number can tell you all of that is pretty amazing.