Sign In
  • Support FanGraphs
    FanGraphs Membership
    FanGraphs Shirts
    FanGraphs Mugs
    Gift a Membership
    Donate to FanGraphs
  • Games
    Ottoneu Fantasy Baseball
    Signup, FAQ, Blog Posts
  • Blogs
    Blog Roll

    FanGraphs
    Podcasts: FanGraphs Audio | Effectively Wild | Chin Music

    FanGraphs Prospects

    RotoGraphs
    Podcasts: The Sleeper and The Bust | Field of Streams | Beat the Shift

    Community Research

    Archived Blogs: The Hardball Times | NotGraphs | TechGraphs | FanGraphs+
    Archived THT: THT Live | Dispatch | Fantasy | ShysterBall
    Archived Podcasts: Stealing Home | Doing It For Bartolo | OttoGraphs | UMP: The Untitled McDongenhagen Project
  • Projections
    2023 Pre-Season Projections
    ZiPS, ZiPS DC
    Steamer
    Depth Charts
    ATC
    THE BAT, THE BAT X
    2023 600 PA / 200 IP Projections
    Steamer600
    2023 Updated In-Season Projections
    ZiPS (RoS), ZiPS (Update)
    Steamer (RoS), Steamer (Update)
    Depth Charts (RoS)
    THE BAT (RoS), THE BAT X (RoS)
    3 Year Projections
    ZiPS 2024, ZiPS 2025
    On-Pace Leaders
    Every Game Played, Games Played %
    Auction Calculator
  • Scores
    Today
    Live Scoreboard, Probable Pitchers
    Live Daily Leaderboards
    Win Probability & Box Scores
    2022, 2021, 2020, 2019, 2018, 2017...
  • Standings
    2022 Projected Standings
    2022 Playoff Odds, Playoff Odds Graphs
    ZiPS Postseason Game-By-Game Odds
    AL East
    AL Central
    AL West
    NL East
    NL Central
    NL West
  • Leaders
    Major League Leaders
    Batting: 2022, 2021, 2020, 2019, 2018, Career
    Pitching: 2022, 2021, 2020, 2019, 2018, Career
    Fielding: 2022, 2021, 2020, 2019, 2018, Career
    Splits Leaderboards
    Season Stat Grid
    60-Game Span Leaderboards (Special)

    KBO Leaders
    Batting, Pitching

    Minor League Leaders
    AAA: Triple-A East, Triple-A West, Mexican
    AA: Double-A Northeast, Double-A South, Double-A Central
    A+: High-A Central, High-A East, High-A West
    A: Low-A West, Low-A East, Low-A Southeast
    R: Appalachian, Gulf Coast, Pioneer, Arizona
    R: Dominican
    WAR Tools
    Combined WAR Leaderboards
    WAR Graphs
    WPA Tools
    WPA Inquirer
    Rookie Leaders
    Batters 2022, Pitchers 2022
    Splits Leaders
    Batters: vs L, vs R, Home, Away
    Pitchers: vs L , vs R, Home, Away
  • Teams
    Team Batting Stats
    2022, 2021, 2020, 2019, 2018, 2017...
    Team Pitching Stats
    2022, 2021, 2020, 2019, 2018, 2017...
    Team WAR Totals (RoS)
    AL East
    Blue Jays  |  DC
    Orioles  |  DC
    Rays  |  DC
    Red Sox  |  DC
    Yankees  |  DC
    AL Central
    Guardians  |  DC
    Royals  |  DC
    Tigers  |  DC
    Twins  |  DC
    White Sox  |  DC
    AL West
    Angels  |  DC
    Astros  |  DC
    Athletics  |  DC
    Mariners  |  DC
    Rangers  |  DC
    NL East
    Braves  |  DC
    Marlins  |  DC
    Mets  |  DC
    Nationals  |  DC
    Phillies  |  DC
    NL Central
    Brewers  |  DC
    Cardinals  |  DC
    Cubs  |  DC
    Pirates  |  DC
    Reds  |  DC
    NL West
    D-backs  |  DC
    Dodgers  |  DC
    Giants  |  DC
    Padres  |  DC
    Rockies  |  DC
    Positional Depth Charts
    Batters: C, 1B, 2B, SS, 3B, LF, CF, RF, DH
    Pitchers: SP, RP
  • RosterResource
    Current Depth Charts
    AL East
    Blue Jays
    Orioles
    Rays
    Red Sox
    Yankees
    AL Central
    Guardians
    Royals
    Tigers
    Twins
    White Sox
    AL West
    Angels
    Astros
    Athletics
    Mariners
    Rangers
    NL East
    Braves
    Marlins
    Mets
    Nationals
    Phillies
    NL Central
    Brewers
    Cardinals
    Cubs
    Pirates
    Reds
    NL West
    D-backs
    Dodgers
    Giants
    Padres
    Rockies
    Offseason Tools
    2023 Opening Day Tracker
    2023 Offseason Tracker
    2023 Free Agent Tracker
    In-Season Tools
    2023 Closer Depth Chart
    2023 Injury Report
    2022 Lineup Tracker
    2023 Payroll Pages
    2022 Probables Grid
    2022 Schedule Grid
    2023 Transaction Tracker
  • Prospects
    Prospects Home
    THE BOARD!
    THE BOARD: Scouting + Stats!
    How To Use THE BOARD: A Tutorial
    Top Prospects List
    Top Prospects
    2023 2022
    AL
    BALCHWHOU
    BOSCLELAA
    NYYDETOAK
    TBRKCRSEA
    TORMINTEX
    NL
    ATLCHCARI
    MIACINCOL
    NYMMILLAD
    PHIPITSDP
    WSNSTLSFG
    AL
    BALCHWHOU
    BOSCLELAA
    NYYDETOAK
    TBRKCRSEA
    TORMINTEX
    NL
    ATLCHCARI
    MIACINCOL
    NYMMILLAD
    PHIPITSDP
    WSNSTLSFG

    • 2022 Preseason Top 100

  • Glossary
    Library
    Batting Stats
    wOBA, wRC+, ISO, K% & BB%, more...
    Pitching Stats
    FIP, xFIP, BABIP, K/9 & BB/9, more...
    Defensive Stats
    UZR Primer, DRS, FSR, TZ & TZL, more...
    More
    WAR, UBR Primer, WPA, LI, Clutch
    Guts!
    Seasonal Constants
    Park Factors
    Park Factors by Handedness
  • Sign In
Help Support FanGraphs


Become a Member No Thanks
Already a member? Log In
  • Intro
  • Features
  • Offense
    • Complete List (Offense)
    • OBP
    • OPS and OPS+
    • wOBA
    • wRC and wRC+
    • wRAA
    • Off
    • BsR
    • UBR
    • wSB
    • wGDP
    • BABIP
    • ISO
    • HR/FB
    • Spd
    • Pull%/Cent%/Oppo%
    • Soft%/Med%/Hard%
    • GB%, LD%, FB%
    • K% and BB%
    • Plate Discipline (O-Swing%, Z-Swing%, etc.)
    • Pitch Type Linear Weights
    • Pace
  • Defense
    • Overview
    • Def
    • UZR
    • DRS
    • Defensive Runs Saved – 2020 Update
    • Inside Edge Fielding
    • Catcher Defense
    • FSR
    • RZR
    • TZ / TZL
  • Pitching
    • Complete List (Pitching)
    • ERA
    • WHIP
    • FIP
    • xFIP
    • SIERA
    • Strikeout and Walk Rates
    • Pull%/Cent%/Oppo%
    • Soft%/Med%/Hard%
    • GB%, LD%, FB%
    • BABIP
    • HR/FB
    • LOB%
    • Pitch Type Linear Weights
    • SD / MD
    • ERA- / FIP- / xFIP-
    • Plate Discipline (O-Swing%, Z-Swing%, etc.)
    • Pace
    • PITCHF/x
      • What is PITCHF/x?
      • Pitch Type Abbreviations & Classifications
      • Heat Maps
      • Common Mistakes
      • PITCHf/x Resources
  • WE/RE/LI
    • RE24
    • Win Expectancy
    • WPA
    • LI
    • WPA/LI
    • Clutch
  • Principles
    • DIPS
    • Regression toward the Mean
    • Replacement Level
    • Sample Size
    • Splits
    • Projection Systems
    • Linear Weights
    • Counting vs. Rate Statistics
    • Park Factors
    • Park Factors – 5 Year Regressed
    • Positional Adjustment
    • Aging Curve
    • League Equivalencies
    • Pythagorean Win-Loss
    • Luck
  • WAR
    • What is WAR?
    • WAR for Position Players
    • WAR for Pitchers
    • FDP
    • fWAR, rWAR, and WARP
    • WAR Misconceptions
  • Business

Plate Discipline (O-Swing%, Z-Swing%, etc.)

by Piper Slowinski
February 18, 2010

Plate Discipline Flash Card 12-29-15

Plate Discipline statistics tell us how often a hitter swings and makes contact with certain kinds of pitches or how often a pitcher induces swings or contact on certain kinds of pitches. We host a variety of plate discipline statistics on the site and draw from two separate data sources (Baseball Info Solutions and PITCHf/x).

These numbers are very useful for determining the type of hitter or pitcher at which you’re looking and changes in these numbers can often be indicative of underlying changes in a player’s approach.

Calculation:

There are many statistics that fit into the category of “plate discipline,” and the basic definitions are provided below. Please remember that we have data for these from two different sources. The PITCHf/x numbers are raw PITCHf/x data, while the BIS numbers have been modified by human coders so they will not always be in perfect agreement and are subject to some measurement error.

O-Swing% = Swings at pitches outside the zone / pitches outside the zone

Z-Swing%  = Swings at pitches inside the zone / pitches inside the zone

Swing% = Swings / Pitches

O-Contact% = Number of pitches on which contact was made on pitches outside the zone / Swings on pitches outside the zone

Z-Contact%  = Number of pitches on which contact was made on pitches inside the zone / Swings on pitches inside the zone

Contact% = Number of pitches on which contact was made / Swings

Zone% = Pitches in the strike zone / Total pitches

F-Strike% = First pitch strikes / PA

SwStr% = Swings and misses / Total pitches

Here are the 2014 plate discipline leaderboards for hitters according to BIS data, and here are the same leaderboards according to PITCHf/x data. You can also find plate discipline data on player pages and can use the “Averages” button to show the player’s numbers next to league average for that year. Additionally, our BIS data updates nightly during the season, but on a delay, so recognize that the most recent games may not be include when using that particular set of stats.

Why Plate Discipline:

Plate discipline stats are very important for hitters and pitchers because they tell you about a hitter’s approach (or hitters’ approaches against a pitcher). We care a great deal about outcome statistics like BB%, K%, wOBA, etc, but we also want to know some of the underlying factors at play. Is this hitter particularly aggressive? We have a metric that tells you how often he swings at pitches outside the zone, or how often he swings in general.

Are we looking at a swing and miss starting pitcher, or a hitter who has trouble making contact? We have a statistic that tells you how often contact is made when the batter swings.

These statistics won’t tell you the entire story, because a batter who swings a lot on the first pitch because he’s aggressive and one who swings a lot on the first pitch because he happened to see a lot of hittable pitches won’t separate out here, but you can typically get a sense of a hitter or pitcher’s approach by looking at the sum total of their plate discipline numbers. Ultimately, a player can succeed with a wide variety of discipline stats, but knowing these will help you identify the player’s style and skill.

How to Use Plate Discipline:

Plate discipline stats are pretty easy to use because you’re just dealing with raw percentages. As long as you’re clear on the numerator and denominator of each stat (listed above) then you should be pretty well prepared to use these values. You know what an average swing rate is and you can compare it to the swing rate of the player in question.

However, you should remember to use plate discipline numbers in the context of other stats. A 95% contact rate means a very different thing if the player is Juan Pierre compared to Victor Martinez. Lots of contact on pitches outside the zone might be good, but if you’re swinging at lots of bad pitches and grounding out weakly, that’s not a very useful event. Additionally, not all pitches inside the zone are created equal, for instance. Ideally, you should swing at pitches against which you can make solid contact, but that set of pitches is not easily defined by in and out of zone in all cases.

Additionally, you have to be careful with sample size. While these numbers are on a per pitch basis which allows them to return large samples of data over the course of a season, you have to remember that at any given point in time, they are subject to random variation. You can’t look at a player’s last 30 PA, observe a 95% contact rate and assume he’s made a meaningful change in his approach or talent level. By the end of a season, you’re more likely looking at a real trend than if you’re looking at one season of ISO, but that doesn’t mean you can make judgements about players with small samples of these stats either.

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. This table is based on BIS data, but PITCHf/x data is similar. It is important to note that the exact definition of the strike zone varies by source and year.

Stat Average
O-Swing 30%
Z-Swing 65%
Swing 46%
O-Contact 66%
Z-Contact 87%
Contact 80%
Zone 45%
F-Strike 59%
SwStr 9.5%

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).

● The definition of the strike zone varies by source, year, and umpire, which means small differences in these numbers should be expected even if the player behaves the same way.

● While these numbers are useful, they do not take into account the game situation or opposing hitter/pitcher, which will have some impact on how a player behaves.

● While high contact is good for hitters and bad for pitchers in general, there is no ideal plate discipline arrangement. You can be a productive player with a high O-Swing% or a bad hitter with a very high Contact%. It depends on a variety of other factors.

Links for Further Reading:

Plate Discipline Stats – FanGraphs

Introducing Plate Discipline Stats – Hardball Times

Plate Discipline Stats in Action – Hardball Times

The Strike Zone Expansion is Out of Control – Hardball Times





Pitch Type Linear Weights
 
HR/FB

Piper was the editor-in-chief of DRaysBay and the keeper of the FanGraphs Library.

Login
Please login to comment
8 Comments
Oldest
Newest Most Voted
Inline Feedbacks
View all comments
Sheldon
12 years ago

What is the definition of F-Strike?

0
Piper Slowinski
12 years ago
Reply to  Sheldon

Hrm, odd…didn’t mean to forget that one. It means “First Pitch strike percentage”. I’ll include it up above.

0
Dan
11 years ago

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?

1
RMR
11 years ago

Is there a reason that Zone% varies so much from BP’s Zone_RT?

0
Billy
10 years ago

On a pitchers fangraphs page in the plate discipline section is that a measure of that player as a hitter or how hitters fare against that particular pitcher?

0
payroll
10 years ago

How come on some player profiles, the 0-swing% and Z-swing% don’t add up to 100%? For example, Scott Cousin’s adds up to 116.2%. Ben Revere’s adds up to 80%.

1
payroll
10 years ago
Reply to  payroll

No, I’m thinking too hard about this. O-Swing% is simply the no. swings at pitches out of the zone / pitches out of the zone. Same for Z-Swing%

0
Scott
10 years ago

why doesn’t contact % plus swSTR% add up to 100 for players?

Are foul balls not factored into one or both of these measurements?

I had always assumed that foul balls were factored into the swinging strike rate….is that not so? Foul ball % may be an interesting metric to track as well in that case. I could also see foul balls being grouped in with contact % since the batter did make some contact…..confused

0
You are going to send email to

Move Comment

Updated: Tuesday, February 7, 2023 7:04 AM ETUpdated: 2/7/2023 7:04 AM ET
Player Linker - @fangraphs - Contact Us - Advertise - Terms of Service - Privacy Policy
sis_logo
All major league baseball data including pitch type, velocity, batted ball location, and play-by-play data provided by Sports Info Solutions.
mlb logo
Major League and Minor League Baseball data provided by Major League Baseball.
Mitchel Lichtman
All UZR (ultimate zone rating) calculations are provided courtesy of Mitchel Lichtman.
TangoTiger.com
All Win Expectancy, Leverage Index, Run Expectancy, and Fans Scouting Report data licenced from TangoTiger.com
Retrosheet.org
Play-by-play data prior to 2002 was obtained free of charge from and is copyrighted by Retrosheet.