Good stuff as usual. I'm wondering, though - is using whiff rate as a predictor of strikeout rate *completely* useless? Even though there are other variables involved, I'd figure that a large disparity between whiff rate and strikeout rate would even out over a season. One example I've noticed this year is Phil Hughes, who's maintained a relatively low whiff rate for most of the year and has recently seen his strikeout rate plummet.

Jeremy, I don't quite understand. How did you compute "count lwts?" Each single count in an at bat times the weight? That is, if a plate appearance goes to 3-2, did you count all four previous counts? What did you do with the final pitch?

I guess I am a bit confused as well.

What is the difference between the "count lwts" and "total lwts"?

How were they computed, as studes asked. Thanks.

Studes, sorry I wasn't clear.

If a PA goes to 3-2, I counted it as 0.062 runs. If you add the four previous counts, you will still eventually get to 0.062. I didn't count the final pitch, since that pitch is what we already know from runs created or linear weights.

I'm still not clear on what you are doing. For example, the value for ending the PA on the 1st pitch is 0.000--yet the OPS+ for these PAs is 130 or so.

And the link you provide for not trying to predict K rate from contact rate is a thick piece on multicollinearity, which will only be understood by people with a better statistics background than many of your readers. Why not just state the principle in simple English?

I think I get it. Instead of giving the batter who puts a ball in play on the first pitch the league avg result of that, you are giving him the expectancy right before that, which is of course 0 lwts runs.

Not sure if this is the best way to do it.

Dave,

Sorry if you took offense to my being glib in directing people to the concept of multicollinearity. It was meant as a throwaway line.

I'm wholly open to the thought that the method I used is completely wrong. I do think the concept to using the final count of each plate appearance has merit in some way or another, so if you have any ideas on how to convert that into runs, I'd love to hear it.

Well, why not give the batter credit for the average result of a PA ending on a given count? For example, in 2009 my quick calc shows that a PA ending on the first pitch was worth around +.04 lwts runs. Give the guy the .04 'count runs', whether or not his physical talent (and luck etc) actually resulted in his gaining .07, or losing .02, on the 1st pitch.

Most analysts like to use the 'through' counts as the preferable set of numbers, but IMO all that really matters is the end result, which are the 'at' counts. If a batter ends a PA on 1-2, who cares if he went thru the favorable 1-0 count on the way there--he ended the PA on (on average) a mediocre pitch to hit.