Interesting article. What is the correlation between Ks per inning and Ks per batter faced and Ks per pitch? Which pitchers move up or down the most in the rankings?

Your strikeout rankings are skewed, of course. NL pitchers have a tremendous advantage since they face their fellow pitchers who account for a high percentage of their strikeouts. NL pitchers generally suffer a 15 to 20% drop in K-rates when they switch to the tougher league. You might do some analytical research and factor that into your rankings. Randy Johnson for instance suffered a decline in K rates, or so it seems, but when you factor in the differential, his K ratio was just as high as last season's and he would rank ahead of every NL pitcher on your list. This needs fine-tuning and a bit more complexity added to serve as a comparision model.

On the flip side, what would K per pitches seen tell us about batting performance? (I'm asking, because I don't know.) I think it would tell us the same thing - good and bad batters.

What about pop-ups? An infield/IF foul fly is nearly as good as a K. If a pitcher gets three pop-ups on five pitches, is't he as effective as someone who strikes out the side on 9 pitches?
I would expect a strong correlation between K's and infield pop-ups, but it would be interesting if there are "hidden" dominant pitchers who don't strike out that many batters but induce a lot of infield flies.

I would argue that the K/BF is a more reactive than predictive stat and therefore not necessarily better than K/IP. While the premise for it is sound, particularly as it relates to walks, looking at it in the past tense is going to raise pitchers who had an anomalously low BABIP up the list, which is something that will tend to regress to the mean and undo some of the predictive qualities of the stat.

I guess the argument for it is that if a BABIP is very low, the pitcher had a commensurately low K rate because he faced fewer hitters. I don't know if I think that will correlate directly though I have no evidence for this.

If I want a nice predictive stat, I might also look at K/(outs+walks+HR allowed). This essentially equalizes the BABIP variability.

Could you try to measure how Strike/Ball ratio affects K/BB ratio it seems to me that it could give you a good correlation and let you see which pitchers were outliers in their K/BB rates.

thats some great stuff, but now my 'steals' of Scott Kazmir(top 10 k/9) and John Lackey(top 10 Ks,k/9) dont look quite so stealthy all of a sudden.

What is the correlation between Ks per inning and Ks per batter faced and Ks per pitch?

Among the pitchers with 162 or more innings in 2005, the correlation between K/9 IP and K/100 Pitches was .963. The correlation between K/BF and K/100 was .985.

Your strikeout rankings are skewed, of course.

My strikeout rankings are no more skewed than any other strikeout measure (including total K, K/9/, and K/BF), which combines the two leagues.

The purpose of this introductory article wasn't to prove that a pitcher in one league is better than a pitcher from the other league. Adjustments to account for the effects of leagues can certainly be made.

but now my 'steals' of Scott Kazmir(top 10 k/9) and John Lackey(top 10 Ks,k/9) dont look quite so stealthy all of a sudden

Do not despair. Lackey was 13th and Kazmir 18th in K/100. They were 3rd and 5th, respectively, in the AL.

I'm not sure that it would necessarily matter, but it occurred to me that another related metric would be how many pitches ended up getting third strikes in two-strike situations. One potential issue I see with the K/100P metric is that not all pitches are created equal; the first two strikes cannot be strikeouts.

One potential issue I see with the K/100P metric is that not all pitches are created equal; the first two strikes cannot be strikeouts.

Yes, but you need the first two strikes in order to get the third.

Your idea about the number or percentage of pitches ending up as third strikes in two-strikes situations is worthy of exploration.

There are differences between the first two strikes and the third, though. Foul balls for instance...

Strikeouts are important, but a pitcher can be quite successful without a high K-rate as long as he is consistently ahead in the count. Only the very best hitters hit well when they have 2-strikes on them. Each PA can be thought of as a race between pitcher and batter. If the pitcher can get 2 strikes on the batter before giving him a good pitch to hit or falling behind in the count he will succeed the vast majority of the time, with or without a strikeout. So the really key stat to monitor for pitchers (and batters) is the % of PA's which end with either an 0-2, 1-2 or 2-2 count. (I exclude 3-2 counts as they are essentially neutral.)

Rob's point is interesting to me, in that I've been suspecting that the A's look at something like that already. It seems to me (as an observation, not with any statistical evidence) that the A's always try to acquire young players with good K/9 numbers, but then when they actually have such a player in hand, they turn around and try to get them to pitch to contact--i.e. get the out as early in the count as possible.

So the really key stat to monitor for pitchers (and batters) is the % of PA's which end with either an 0-2, 1-2 or 2-2 count. (I exclude 3-2 counts as they are essentially neutral.)

Are we in some kind of time warp here? I thought this blog and others like it had moved beyond such observation arguments. Where's the data? Sounds like something right out of Joe Morgan.

Rich has put together an interesting find that advances the DIPS theories. You don't have to subscribe to its predictive value, but the data is sound and fits in with other DIPS-related discussions. If you value K/9, this indicates that K/P is even more worthy. That's all.

Example:

Pitcher A:
Pitches: 90
Strike-outs: 10
BF: 30
HR Allowed: 4
Walks Allowd: 0

Pitcher B:
Pitches: 90
Strike-outs: 8
BF: 30
HR Allowed: 0
Walks Allowed: 0

Which line would you rather have? A homerun allowed (park adjusted) should also be a part of any "Defensive independent stat".

vr, Xeifrank

I have to ask the question that any self-respecting Mariners fan would ask -- how would Felix have fared in comparision, if he were not eliminated based on IP?

I really enjoyed this blog. Have you considered an out to pitch ratio. Granted the first two pitches have a lower out percentage then the remaining pitchers. I think this stat could be used to evalute when a pitcher gets traded to a team with a modifier for a Better/Worst defense and differnt leagues and ballparks. When Randy Johnson went to the yanks you plug his out to pitch ratio and then modify it according to the new league ball park and Defense. It was hinted at earlier the ability to throw a 4 and 5 can also make the pitcher very effective.

If you're interested, I look at pitches per strikeout here.

I look at pitches per strikeout here.

For the record, pitches per strikeout are not the issue here. I'm measuring strikeouts per pitch, not the other way around.

Strikeouts per pitch (or K/P) takes into account every pitch thrown, including those on strikeouts, walks, hit by pitches, home runs, and balls in play.

David is only evaluating the number of pitches when the result is a strikeout. That is neither here nor there in my study and, unlike K/P, it has no correlation with run prevention.

Richard,

I've got a pretty significant question here, one which I feel isn't asked nearly often enough when people introduce new stats or measures.

What's the year to year correlation in this for players? As in, is this more representative of a skill than other strikeout measures? Does this really give us a better idea at their true talent levels?

If not, then what exactly can this be used for? Would inserting it into DIPS formula improve things? (I suspect it would, but I'd like to know.)

You've explained pretty well why this could be useful, but at the same time, it's all pretty speculative. What's the practical use of this knowledge? Either of the two setups for usefullness I suggested would do nicely.

I've now read Rich's piece four or five times. His thesis is that pitchers who strikeout lots of batters and are efficient in their use of pitches are very effective pitchers. I don't dispute this. What I dispute is that efficiency comes from striking out batters on fewer pitches. From my read of the article, this appears to be what Rich is implying. The point of the above chart at my site is to demonstrate that the efficiency doesn't come from fewer pitches per strikeout, but from other places.

I think David Pinto has a point. The problem is this statement:

"Just as striking out the side in order is preferred over getting all three outs via the K regardless of the number of batters faced, a pitcher who strikes out hitters on three pitches is more effective than those who take five or six to get the job done. By definition, he is missing bats a higher percentage of the time and is also more likely to pitch deeper into games and record a greater number of outs than his counterparts."

1. Rich - You say later that "pitches per strikeout are not the issue here." That seems to be incongruous with the statement above.
1. If it is the issue, then I would say that pitchers who work counts and set up batters for strikeouts can be just as effective as pitchers who strike out batters on three pitches.
2. By defining pitchers who strike out batters on three pitches, all you are doing is isolating the "power" pitchers, not necessarily the most "effective" pitchers. I'm not sure it's fair to assume that such power pitchers would last longer in games or get more outs. In order to record a strikeout a pitcher must throw three pitches, which is less effective than the pitcher who gets a ground ball out on one pitch. Greg Maddux, in his prime, could throw 80 pitches over nine innings and complete a game in an hour and a half. He was the most effective and efficient pitcher I've ever seen, but he couldn't have cared less where he fit in on the charts above.

There are many ways to skin a cat. Up to that part where it breaks down K/Pitches, there was a lot of merit to the analysis. I would disagree, though, with the apparent conclusion that striking out batters on three pitches represents the ideal for pitching effectiveness - if that is what Rich is saying.

This is valuable and creative research. I suggest doing the same as regards walks, a much more important category than strike outs, considering that the linear weights value of a walk is minus 1/2 run to a pitcher; whereas a strike out has a LW value of just plus 1/10 run to a pitcher.

Also how about OUTS PER PITCH? Could be something significant there, also.

Robby Bonfire........phillies.mostvaluablenetwork.com