Advanced Stats- Offense (Part 3)

At the conclusion of Part 2 of offensive statistics I put forth the query of what is more important, OBP or SLG? While OPS is a very useful statistic, there is actually a more effective statistic. This statistic is called Weighted On Base Average.
Weighted On Base Average (wOBA) is a statistic that takes different offensive outcomes and gives them a number, this number we call a weight. The weights are determined by something we call run value. I'm not going to go into a lot of detail about run values but if you would like to learn more follow the link at the end of the post. The value is then multiplied by 15% to make it look more like an On Base Percentage. So whenever you see wOBA think OBP. A .400 wOBA is well above average, .340 is average, and under .300 is well below average.
Here are the weights-
non intentional walk- 0.72
Hit By pitch- .75
Single- 0.90
Double- 1.24
Triple- 1.56
Home Run- 1.95
(Some people like to include reaching base on an error, worth 0.92)
So in order to complete the formula you multiply every outcome by the weight, then add them together. You divide that number by the amount of plate appearances a player has.
Now to answer the question, what is more important. It turns out that getting on base more will lead to a higher wOBA. Let's use two players as examples. Jason Bartlett is the first player the second player is one of my personal favorites, Pablo Sandoval.
Jason Bartlett has a triple slash line of .391/.541/.932 (that's OBP/SLG/OPS). Pablo Sandoval's triple slash line is .378/.549/.927. The two are relatively close (.05 difference) in terms of OPS, Bartlett higher OBP, Sandoval higher Slugging. Bartlett just happens to have a .408 wOBA, top 10 in baseball. Sandoval's is considerably lower at .391 (a .17 difference). Bartlett's extra on base skills helps him maintain a higher wOBA. Remember when looking at wOBA think OBP, when you do this you see that both players are well above average hitters this year, Bartlett being the better of the two.
But why do we need another offensive statistic? What makes this so special? The secret behind wOBA will be revealed in part 4, the final section of Advanced Stats- Offense.


http://www.tangotiger.net/lwbymob.htm