Thursday, May 8, 2014

Understand Sabermetrics : On Base Percentage (OBP)

The entire premise of the movie Moneyball, and the whole moneyball craze, was the thought that defense did not matter, home runs did not matter, batting average did not matter, the only thing that mattered was getting on base. I , without doing hours of research and still not getting a 100% correct  answer, would say that OBP was the first SABR stat that started it all when it comes to being in the mainstream media and being used to calculate value for players. OBP basically calculates the players ability to reach base without the help of a fielding error, fielders choice, dropped third strikes, fielders obstruction, or catchers interference.

The highest OBP ever posted, career wise, was Ted Williams when he posted a .482 OBP. The lowest ever was .194 OBP by Billy Bergen. The highest total for a single season was Barry Bonds when he posted a staggering .609 OBP.

 Here is how OBP is calculated:

On-base percentage (OBP) = (H + BB + HBP) / (AB + BB + HBP + SF)

Basically what you do is add the players number of hits, walks, and hit by pitches, and put that number aside to be used later. You then add the number of at bats, walks, hit by pitches, and sacrifice flies while putting that number aside. You then will divide the first number you got by the second number you got and you will have the players OBP.

Let's use a Yankee's 2011 season stats as a way to hopefully simplify it. Let's use Nick Swisher only because he was the first "moneyball" player that Billy Beane ever drafted using the system because he was the only player that he and traditional scouts could agree on.

In 2011 Nick has 137 hits, 95 walks, and 5 hit by pitches adding up to 237.

He had 526 at bats, 95 walks, 5 hit by pitches, and 8 sacrifice flies adding up to 634.

You will then divide 237 by 634, getting Nick's OBP of .374.

The modern era league average for OBP is considered to be .340. A good way to measure a "good" OBP is to compare it to the players batting average. Nick's 2011 batting average was only .260, meaning he has a OBP 114 points higher then his batting average. Anything over 100 points higher then your batting average is above average at getting on base. Anything 50-100 points is considered below average to average. If it is possible to be below 50 points would mean you are terrible at getting on base. Nick Swisher, Mr. Money Ball, is a great example of what Billy Beane was trying to draft when this craze started.

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Sorry for the Capatcha... Blame the Russians :)