Run Preventing Events Update

Today, I’ll return to the batted balls versus pitchers theme of last winter. To review, an at bat can result in any of the following events:

• Strikeout
• Base on balls
• Hits batsman
• Ground ball
• Line drive
• Outfield fly
• Infield fly

Three of those events are generally favorable events for pitchers:

• Strikeout (SO)
  
• Ground ball (GB)
  
• Infield fly (IFF)
  

I will call these run preventing events (RPE). Of course, a ground ball is not as easy an out as a strikeout or an infield fly and can have a negative result for a pitcher. However, inducing a lot of ground balls will help to prevent runs over the course of a season. On the other hand, it is good for pitchers to avoid, for the most part, the following events:

• Base on balls
• Hits batsman
• Line drive
• Outfield fly

Last year, I constructed a stat called Run Preventing Event Percentage (RPE%) = (SO + GB + IFF)/BFP where where BFP = Batters Faced by Pitcher. Striking out batters and inducing grounders have been shown to be repeatable skills. Getting batters to hit infield flies is not stable from year to year (correlation = .10 between 2005 and 2006). However, infield flies are relatively rare compared to other batted ball types and including them does not change the RPE% substantially in most cases. Plus, I suspect (without statistical evidence) that this is a real ability for some power pitchers.

It turns out that RPE% is fairly stable with a .66 correlation between 2005 and 2006. It can also be considered a fielding independent stat because, although the end result is not independent of fielders, getting a grounder or infield fly to happen in the first place has nothing to do with fielders. It is as stable or more stable than FIP but it is not weighted and thus does not explain as much about runs allowed. RPE% is just an exploratory stat for now.

There are 47 American League starters with 60 or more innings pitched so far. Table 1 lists the RPE% rankings for Tigers starters. Table 2 lists the top 20 pitchers in the league. The raw dataused for the calculations were extracted from The Hardball Times database. We can see that Jeremy Bonderman (RPE%=58.5) ranks very well (7th in the AL) as he does on most fielding independent stats. As with the FIP stat discussed yesterday, Justin Verlander does not rank especially well on this statistic: 24th at 53.2%. Because he is good at stranding base runners, I suspect his RPE% with runners on base is better. Still, I believe he will need to improve his FIP components (more ground balls, more strikeouts or fewer walks) in order to keep his ERA down. Nate Robertson (25th) and Chad Durbin (30th) rank a little better on this statistic than they did on FIP.

Table 1: Run Preventing Events for Tigers Starters through June 9, 2007

Rank	Pitcher	BFP	K	GB	IFB	RPE	RPE%
7	Bonderman	299	64	103	9	176	58.8
24	Verlander	319	56	102	12	170	53.3
25	Robertson	296	34	119	5	158	53.2
30	Durbin	296	36	109	10	155	52.4
45	Maroth	294	22	98	9	129	44.0

Table 2: Run Preventing Events for Top 20 AL Starters through June 9, 2007

Pitcher	Tm	BFP	K	GB	IFB	RPE	RPE%
Carmona	CLE	307	33	163	2	198	64.6
Beckett	BOS	285	67	104	11	182	63.7
Wang	NYA	256	29	127	5	161	62.8
Burnett	TOR	360	96	117	8	221	61.3
Halladay	TOR	280	46	121	4	171	60.9
Meche	KC	378	68	148	12	228	60.3
Bonderman	DET	299	64	103	9	176	58.8
Bedard	BAL	343	95	101	5	201	58.7
Gaudin	OAK	328	51	127	9	187	57.1
Cabrera	BAL	366	68	130	11	209	57.0
Escobar	LAA	298	52	105	12	169	56.9
Sabathia	CLE	365	83	114	9	207	56.6
Blanton	OAK	366	63	130	12	206	56.2
Pettitte	NYA	349	46	140	9	195	56.0
Shields	TB	387	83	117	15	216	55.8
Guthrie	BAL	255	42	95	4	141	55.3
Buehrle	CHA	279	48	97	8	153	54.8
Loe	TEX	283	35	118	2	155	54.8
Santana	MIN	344	96	79	11	187	54.3
Haren	OAK	374	76	108	17	201	53.7