Friday, October 19, 2012

Introducing Precision Index

The Jays' Ricky Romero walks almost as many batters as he strikes out per game.

Readers of my game previews will often hear me talk about the difference between a pitchers k/9 and his bb/9. Obviously pitchers with large differences are striking out a lot of guys and walking few or at the very least doing at least one exceedingly well. I decided to take a look at the list of qualifying starting pitchers and see who's differences were the greatest and the closest. We can call this a pitchers Precision Index, a measurement of how precise a pitcher is with his pitches.

Below is a list of the top five worst pitchers using k/9-bb/9 differential:

Name
Team
K/9
BB/9
PI
Ricky Romero
Blue Jays
6.17
5.22
0.95
Henderson Alvarez
Blue Jays
3.8
2.59
1.21
Barry Zito
Giants
5.57
3.42
2.15
Kevin Correia
Pirates
4.68
2.42
2.26
Aaron Harang
Dodgers
6.56
4.26
2.3

The winner for least precise pitcher in baseball goes to the Blue Jays Ricky Romero with a difference of less than 1 between his k/9 and bb/9, Ricky is dangerously close to offering up as many strike outs per game as he does walks. Henderson Alvarez comes in second who doesn't actually have a terrible bb/9 but strikes out basically no one. A quick way to check our work would be to see how the low PI pitchers match up with a list of players by WAR for the season. Players on the bottom of the Precision Index list should also be at the bottom of the WAR list.

Romero
0.5
tied for 4th worst
Alvarez
0.5
tied for 4th worst
Zito
0.8
6th worst
Correia
0.9
7th worst
Harang
1.5
tied for 15th worst

Four of the five are in the bottom ten in baseball with Harang still solidly in the bottom 20. Now let's look at the players with the greatest differentials.

Name
Team
K/9
BB/9
PI
Max Scherzer
Tigers
11.08
2.88
8.2
Cliff Lee
Phillies
8.83
1.19
7.64
CC Sabathia
Yankees
8.87
1.98
6.89
Cole Hamels
Phillies
9.03
2.17
6.86
R.A. Dickey
Mets
8.86
2.08
6.78

No shockers here. In addition to demolishing the Yankees in the playoffs Max Scherzer also leads the league in strike out to walk differential. Scherzer's power is derived from his incredible leauge leading strike out ability paired with an average low walk number. Cliff Lee had very few wins but comes in second on this list and most exciting of all is that our list contains Mister R.A. Dickey, is their any list of top stat leaders that doesn't contain this man? I think not. Let's check our work again.

Scherzer
4.6
tied for 12th
Lee
4.9
tied for 8th
Sabathia
4.8
tied for 11th
Hamels
4.5
tied for 13th
Dickey
4.6
tied for 12th

This list doesn't hew as closely to the other but still has all the top PI pitchers as top 20 WAR guys. Obviously we aren't breaking new ground here, we always knew that players with a lot of strike outs and few walks were good but I do think Precision Index represents a fun and simple way to get that information.

2 comments:

  1. In other news, Angel Pagan is going to the World Series!

    ReplyDelete
  2. I am pumped for him, he had a great year!

    ReplyDelete