Called-Strike-Plus-Whiff Rate (CSW%)
Also known as: CSW%, CSW rate
CSW% is a pitching metric that combines called strikes and swinging strikes (whiffs) as a share of total pitches thrown, measuring how often a pitcher generates a strike without the ball being put in play.
CSW% answers a simple question about a pitch or a pitcher's overall arsenal. This means out of every pitch thrown, how often does it produce a strike that isn't hit into play. This means either. This is because the hitter takes it for a called strike or swings and misses entirely? By combining both outcomes into one number, CSW% avoids relying only on whiff rate (which ignores well-located pitches hitters correctly take for a strike) or only on called-strike rate (which ignores pitches with excellent late movement that get chased and missed).
CSW% is popular in modern pitching analysis. This is because it correlates well with overall pitch effectiveness and strikeout rate without needing a full plate appearance to resolve. This means it can be calculated pitch by pitch. This makes it useful for evaluating an individual pitch type just as easily as an entire outing. A pitcher or a specific pitch with a high CSW% is generating strikes efficiently, whether through deception, movement, or location, without needing to rely on batted-ball luck.
Example
A pitcher throws 90 pitches in an outing, generating 18 called strikes and 9 swinging strikes. This means a combined 27 non-contact strikes, or a 30% CSW% for the game.
Why it matters
CSW% gives pitchers and coaches a batted-ball-independent way to judge whether a pitch or an outing was genuinely effective, rather than relying on results that were also shaped by defense and luck on balls in play.
Common mistakes
- Comparing CSW% across very different competition levels without context, since called-strike and whiff tendencies shift with hitter aggressiveness and umpire zone at every level.
- Using CSW% as the only measure of a pitching outing while ignoring walks, hard contact allowed, and overall command.
Frequently asked questions
What is considered a good CSW% for a pitcher?
It varies by level and pitch mix. But a CSW% meaningfully above whatever the typical range is for a given level and competition generally indicates an effective, well-located pitch or outing.
Related terms
- Zone Contact RateZone contact rate is the percentage of swings at pitches inside the strike zone that result in contact. This means a core measure of basic bat-to-ball ability on pitches a hitter should be equipped to handle.
- Chase ContactChase contact rate is the percentage of swings at pitches outside the strike zone that result in contact, measuring how well a hitter defends the plate even when they have made the decision to swing at a bad pitch.
- Strikeout RateStrikeout rate (K%) is the percentage of plate appearances that end in a strikeout — elevated K% reduces a hitter's value by eliminating batted-ball outcomes entirely.
- First-Pitch Swing RateFirst-pitch swing rate is the percentage of plate appearances in which a hitter swings at the very first pitch (the 0-0 count), used as a simple measure of a hitter's early-count aggressiveness.
Related guides & benchmarks
Put this into your swing
SwingVantage can spot this in your own swing — free to start.
See a sample Baseball report first