Sabermetrics Glossary: Called Strike Plus Whiff Rate (CSW)
Called Strike Plus Whiff Rate (CSW) is a new statistic that has popped up in the last few years that takes pitcher metrics one step further. Everybody is probably familiar with Swinging Strike Rate, which is simply the number of swinging strikes a pitcher gets divided by the total number of pitches they throw.
By adding in called strikes to this calculation, we now give credit to pitchers for strikes thrown that aren’t swung at. This makes sense because a called strike is just as effective as a swinging strike. While it is certainly easier to get a called strike than a swinging one (given that hitters decide to take many pitches before they even leave the pitcher’s hand), it still makes sense to have a metric that gives credit to those called strikes.
This stat hasn’t become mainstream enough to appear on statistic leaderboards at this point, so for right now it is a bit tough to find. We will have monthly updates on this statistic as the season progresses.
To offer some context, here is the breakdown of all pitches thrown in 2019 as they relate to CSW rate.
Total pitches thrown last year: 732,473
Called Strike Rate on those pitches: 16.4%
Swinging Strike Rate on those pitches: 11.2%
CSW Rate on those pitches: 27.7%
You see that the league average is 27.7%, so that’s a good thing to keep in mind when you see these numbers listed for individual pitchers. Here are the leaders from the 2019 season.
Here are the leaders when we just use starting pitchers (1,500 pitches thrown minimum).
We can use the Statcast pitch-by-pitch data to isolate every individual pitch for this study. Here are the best 25 pitch offerings last year by this CSW metric.
Be sure to check back during the season for in-season updates on this, it could really give you an edge in identifying breakout pitchers before the rest of the world buys into them.