Plate Discipline (O-Swing%, Z-Swing%, etc.)
Plate Discipline statistics tell us how patient a player is at the plate, and how good they are at making contact with pitches. There are a wide number of these stats:
O-Swing%: The percentage of pitches a batter swings at outside the strike zone.
Z-Swing%: The percentage of pitches a batter swings at inside the strike zone.
Swing%: The overall percentage of pitches a batter swings at.
O-Contact%: The percentage of pitches a batter makes contact with outside the strike zone when swinging the bat.
Z-Contact%: The percentage of pitches a batter makes contact with inside the strike zone when swinging the bat.
Contact%: The overall percentage of a batter makes contact with when swinging the bat.
Zone%: The overall percentage of pitches a batter sees inside the strike zone.
F-Strike% – The percentage of first pitch strikes.
SwStr%: The percentage of total pitches a batter swings and misses on.
FanGraphs carries plate discipline statistics based on both Baseball Info. Solutions (BIS) data as well as Pitch f/x data. There are some minor differences between the two systems. The Pitch f/x section presents raw Pitch f/x data broken down according to defined baselines, while the BIS section takes the Pitch F/x data and uses human scorers to modify classifications.
Here are the batter plate discipline leaderboards according to BIS data, and here are the same leaderboards according to PITCHf/x data.
Context:
Please note that the following chart is meant as an estimate, and that league-average for all of these stats varies on a year-by-year basis. To see the league-average plate discipline stats for every year from 2002 to the present, check the FanGraphs leaderboards.
| Stat | Average |
|---|---|
| O-Swing | 30% |
| Z-Swing | 65% |
| Swing | 46% |
| O-Contact | 68% |
| Z-Contact | 88% |
| Contact | 81% |
| Zone | 45% |
| F-Strike | 59% |
| SwStr | 8.5% |
Things to Remember:
● These statistics are useful for evaluating hitters and pitchers, with SwStr% being especially important when looking at pitchers.
● Swinging strike percentage (SwStr% — swinging strikes per pitch) should not be confused with whiff rate (swinging strikes per swing).
Links for Further Reading:
Plate Discipline Stats – FanGraphs
4
What is the definition of F-Strike?
Hrm, odd…didn’t mean to forget that one. It means “First Pitch strike percentage”. I’ll include it up above.
What exactly does the zone percentage quantify? Is it the % of pitches found within a standardized or by-the-book strike zone regardless of the call made by the umpire? Or perhaps a sum of the in-zone pitches plus pitches that are called strikes by the umpire even if they’re outside the zone?
Is there a reason that Zone% varies so much from BP’s Zone_RT?