Continuing the explanation of the three slash takes us to the middle value, On-Base Percentage (OBP). On-Base Percentage really became popular during the Moneyball era (if you haven't seen the movie, I urge you to do-so! It is a great movie, and it stars Brad Pitt as Billy Beane, so there's that. Other choices: Reading the book). The theory was that players were more valuable in their ability to get on base any way possible rather than just hitting their way onto base. So, unlike Batting Average, On-Base Percentage includes things like walks, and hit-by-pitches along with pure hits. So, let's get to it:
On-Base Percentage
On-Base Percentage is a little more involved than Batting Average, but it's totally manageable. Many times (most time, basically 100% of the time) you'll find that the OBP is higher than the batting average. Basically the reason for OBP is to see how often the player avoids making an out. Having a plate appearance without costing the team an out, as you can imagine, would be pretty valuable considering you only get 3 outs per inning to do what you gotta do.
So, back to the numbers. How is On-Base Percentage calculated? Here you go:
Now, you're probably thinking, what in the hell do all of those letters even mean. Well, I'll tell you! Let's look at the numerator first.H = Hits. Pure hits. Got on base, no funny business.
BB = Walks. Had a good enough eye to let 4 bad pitches fly by and give you a free base.
HBP = Hit By Pitch. Either the pitcher did something wrong, or someone was being a jerk.
These are the only ways that you could possibly get on base without drawing an out.
Now the denominator (you like those technical terms, don't you?).
AB = At-Bats. We talked about this last post.
BB = Walks
HBP = Hit By Pitch
SF = Sacrifice Fly. This is when there is someone already on base and the hitter sacrifices an out on himself to further the runner who is already on base into a better position to score, or to score. Yes, it doesn't help your numbers very much, but it does help the team, so it ain't all bad.
Here's an example of a sacrifice fly brought to you by B.J. Upton in the 2013 season.
Again, OBP is a percentage, so when you see an OBP of .400 that means that whoever that player is, he's averaging a 40% rate of getting on base without making an out.
Now, what's a good OBP, and what's a bad OBP? According to Fangraphs (which, by the way, is a really good place to go if you have questions about statistics) here's how OBP is interpreted:
For a little comparison, I've marked where 3 teams finished in their team OBP for 2013. The Braves finished out the season with an average team OBP of .321. Guess who won the World Series. The Red Sox (team OBP of .349 - highest in baseball). Guess who finished dead last in the standings. The Marlins (team OBP of .291 - lowest in baseball). Getting on base is CRUCIAL.