There are so many baseball stats flying around. We house dozens of columns and tables on our player pages and it can be overwhelming to learn *everything, *from their context to their derivisions and why they actually matter.

Staff writer and data scientist Jeremy Seigel has gathered all our stats and created one massive encyclopedia to keep track of it, written in laymen terms. Get to know every advanced baseball stat, how they’re calculated, and relevant links to great research done inside the sabermetric community.

**2-Str%**

Two-Strike Percentage (2-Str%) tells us how often a hitter faces a two-strike count or a pitcher arrives at a two-strike count. For example, if a hitter has a 25% 2-Str%, this means 25% of the pitches he has faced have come with 2 strikes. Hitters with high 2-Str% typically either have high whiff rates and/or like to work counts.

*2-Str% = Pitches seen in 2-strike counts / pitches seen*

Using 2-Str% to Predict Pitcher Breakouts – Nick Gerli, Pitcher List

Application of 2-Str% – Dan McNamara, Pitcher List

**2-Str% (P)**

Two-Strike Percentage (Pitcher) (2-Str%(P)) tells us how often a pitcher’s pitch is thrown faces a two strike count against all the other pitches they throw in a two-strike count. For example, if a pitcher’s slider has a 25% 2-Str%, this means 25% of his two-strike pitches were sliders. Pitchers with high 2-Str% typically get ahead in the count often, leading to better results. 2-Str% can also be used on an individual pitch level. If a pitcher has a high 2-Str% on his curveball, that means he is more likely to use it as a put away pitch than early in the count.

*2-Str% (P) = Pitches of that pitch type thrown in 2-strike counts / total pitches thrown in 2-strike counts*

**2-Str O-Swing%**

2 Str O-Swing% can be either a hitter or pitcher stat. It tells us how often a hitter chases pitches out of the zone, or how often a pitcher forces the opponent to chase a pitch out of the zone, exclusively with two strikes. A hitter with a high 2-Str O-Swing% likely struggles with plate discipline, especially when behind in the count. A pitcher with a high 2-Str O-Swing% likely has good putaway stuff.

*2-Str O-Swing% = Pitches swung at out of the zone/ pitches thrown out of the zone (2-strike counts only)*

**aLoc%**

aLoc% measures the percentage of pitches located on the pitcher’s arm side. Given a right-handed pitcher, If we were to draw an imaginary vertical line that splits the strike zone in half, aLOC% tracks the portion of pitches that land to the right of the line (and vise versa for a lefty). The height and strike zone status are irrelevant.

*aLOC% = Pitches located on pitcher’s armside / pitches thrown*

How pitch location impacts batted balls – Jonah Pemstein, FanGraphs

The importance of pitch location – Patrick Brennan

**AVG**

Batting Average (AVG) is one of the most basic offensive stat. It measures the percentage of at bats a hitter takes that end in a hit. All hits, whether it is a single or home run, count the same. Any plate appearance that does not constitute an at bat, such as a walk, hit batsman, or sacrifice is filtered out of the formula.

*AVG = hits / at bats*

Lesson on Batting Average – Baseball Hall of Fame website

Why We Should Not Rely on Batting Average – John Edwards, Sporting News

**BABIP **

Batting Average on Balls in Play (BABIP) determines how often a batter gets a hit when he makes contact and the ball stays in the field of play. Thus, walks, strikeouts, hit batsmen, and home runs are not included in the calculation. A high BABIP can be an indication that the batter makes consistently solid contact and/or uses his speed to beat out infield hits. However, in smaller samples, a high BABIP may be a result of luck.

*BABIP = (hits – home runs) / (balls in play – home runs )*

BABIP calculation – Piper Slowinski, FanGraphs

How Both Luck and Skill Can Influence BABIP – Devan Fink, Beyond The Box Score

**BACON **

Batting Average on CONtact (BACON) determines how often a batter gets in hit when he makes contact. Thus, walks, strikeouts, and hit batsmen are not included in the calculation. BACON is very similar to BABIP, except home runs are also included. A high BACON can be an indication that the batter makes consistently solid contact and/or uses his speed to beat out infield hits.

*BACON = Hits / Batted Balls*

Why BACON (called CTBA in article) is more useful than BABIP – Shawn Childs, Sports Illustrated

**BB%**

Walk rate (BB%) is the proportion of plate appearances that end in a walk. It can be used as either a hitter or a pitcher stat. A hitter with a high walk rate likely has great plate discipline, whereas a pitcher with a low walk rate likely has great control.

*BB% = walks / plate appearances*

A Beginner’s Guide to Plate Discipline Metrics – Dave Cherman, Pitcher List

How Walk Rate is One of the Most Stable Offensive Statistics – Piper Slowinski, Fangraphs

**Behind%**

Behind% tells us what portion of a given pitch a pitcher throws when he is behind in the count. This is defined by all times when the count (before the pitch) is 2-0, 2-1, 3-0, or 3-1. If a pitcher has a high Behind% on his fastball, that means he often turns to it when he needs a strike.

*Behind % = pitches thrown when behind in the count / pitches thrown*

The Importance of the Count – Stanley M. Katz, SABR

**Brl%**

Every batted ball has an exit velocity (speed of the ball immediately after contact) and a launch angle (vertical angle the flight of the ball makes). If, based on these two factors, the batter is determined to have a probability of 50% or greater to get a hit as well as a 1.500 or greater expected slugging percentage (xSLG), the batter is assigned a barrel (Brl). Brl% simply measures the percentage of batted balls that become barrels for a given hitter. The best power hitters in the game consistently rank at the top of the Brl% leaderboards, as it can be a great indication of future positive results.

*Brl % = barrels / balls in play*

Calculation and Importance of Barrels – Mike Petriello, MLB.com

Why Barrels are so important for fantasy baseball – Elliott Baas, Roto Baller

How Contact Management can be a Pitcher Skill – Craig Edwards, FanGraphs

How different Statcast Measures correlate with Power Metrics– Al Melichor, FanGraphs

**Cent%**

Cent % measures the proportion of batted balls that are hit to the middle of the field. Each batted ball is placed in one of three categories: pull, opposite field, or center. Cent% gives us the percentage that was classified as center

*Cent % = Centerfield BIP / BIP*

The importance of Spray Angle – Nick Gerli, Pitcher List

**Con%**

Contact rate (Con %) tells us how frequent a better makes contact (or pitcher induces contact). It measures the proportion of swings where the ball is hit. A foul ball still counts as contact (a foul tip does not). Contact rate is the exact opposite of whiff rate

*Con % = (Swings – Whiffs) / Swings*

Importance of Plate Discipline and Contact Rate – Nathan Dokken, Fantrax

**CS%**

Called strike rate (CS%) tell us how often a pitch ends up as a called strike. Every pitch, whether a swinging strike, ball, or batted ball, counts toward this formula. CS% can be a good indication of a pitcher’s command. For a hitter, a high CS% can indicate patience or passiveness at the plate.

*CS% = Called Strikes / pitches thrown*

The Art of Called Strikes – Tim Heaney, ESPN

How to use Called Strike Rate in Player Analysis – Matt Williams, NBC Sports Edge

**CSW%**

Called Strikes Plus Whiffs (CSW%) is a simple yet very effective way to evaluate a pitcher. It measures the proportion of pitches thrown that end up as a called strike or a swing-and-miss (including a foul tip). It essentially combines two important stats (CS% and SwStr%) into one. CSW% is a good indicator of future success, even in small samples.

*CSW% = (Called Strikes + Whiffs) / pitches thrown*

Intro to CSW – Alex Fast, Pitcher List

**Early%**

Early% tells us what portion of a given pitch a pitcher throws early in the count. This is defined by all times when the count (before the pitch) is 0-0, 0-1, 1-0, or 1-1. If a pitcher has a high Early% on his fastball, that means he often starts off plate appearances with this pitch.

*Early % = pitches thrown early in count / pitches thrown*

The Importance of the Count – Stanley M. Katz, SABR

**Early BIP%**

Early BIP% tells us how often a batter puts the ball in play (or pitcher induces a ball in play) early in the count. This is defined by all times when the count (before the pitch) is 0-0, 0-1, 1-0, or 1-1. A batter with a high Early BIP% is likely an aggressive contact hitter. A pitcher with a high Early BIP% likely pitches to contact and is efficient when he performs well.

*BIP % = balls in play / pitches thrown ( early in count only)*

Swinging at the First Pitch – James Gentile, FanGraphs

**ECS%
**Early Called Strike % (ECS %) measures a pitcher’s called strike rate on early counts. This is defined by all times when the count (before the pitch) is 0-0, 0-1, 1-0, or 1-1. Every pitch, whether a swinging strike, ball, or batted ball, counts toward this formula. A pitcher with a high ECS% generally gets ahead in the count consistently.

*ECS% = Called Strikes / pitches thrown ( early in count only)*

The Importance of the Count – Stanley M. Katz, SABR

The Art of Called Strikes – Tim Heaney, ESPN

**ERA**

Earned run average is one of the most commonly-used performance metric for a pitcher. It measures how many earned runs a pitcher allows on a nine inning rate. An earned run is a run allowed that is determined to be the pitcher’s responsibility i.e., not as a result of an error. Although all pitchers strive for a low ERA, it can include a good amount of luck, especially in a small sample.

*ERA = (Earned Runs/ Innings Pitched) * 9*

Why ERA shouldn’t be used as much – Bryan Grosnick, Beyond the Box Score

**EV**

Each time the batter hits the ball, their exit velocity (EV) is measured as the speed of the ball directly after contact. When you see it on a player page, EV represents a hitter’s (or pitcher’s) average exit velocity on all batted balls. Exit velocity is a great measure of quality of contact, as high exit velocity generally leads to good results.

*EV = Average of all exit velocities*

Intro to Exit Velocity and How to Increase it – Alyssa Johnson, Rapsodo

How different Statcast Measures correlate with Power Metrics– Al Melichor, FanGraphs

Why Exit Velocity is Important – anselo13, FanGraphs Community Research

Why Average Exit Velocity can be a Flawed Metric – Jeremy Siegel, Pitcher List

**Ext.**

Ext. tells us the pitcher’s extension toward the plate. It measures the distance in feet the pitcher’s release point is from the front of the rubber. This benefits taller pitchers, as releasing the ball closer to the plate can be a significant advantage. Extension can be important to evaluate a pitcher’s mechanics and how they may be able to improve.

*Ext. = A pitcher’s average extension from mound to ball release*

Why pitchers should release the ball closer to the plate – Kyle Boddy, Driveline

How extension can give a pitcher a major advantage- Devan Fink, FanGraphs

**F-Strike%**

First Strike % (F-Strike%) tells us how often a pitcher gets the first strike on a batter, whether it be a called strike, whiff, or foul ball. F-Strike % is important because getting a 0-1 count is one of the biggest advantage a pitcher can have. It often can lead to good results in the future

*F-Strike % = First pitch strikes / Batters Faced*

The Importance of the Count – Stanley M. Katz, SABR

The Value of a First Pitch Strike – Jerry Weinstein, Weinstein Baseball

**FB EV**

Each time the batter hits the ball, their exit velocity (EV) is measured as the speed of the ball directly after contact. Fly Ball Exit Velocity (FB EV) measures the average exit velocity on fly balls only. Any ground ball, line drive, or popup is not included in this calculation. Batters with high FB EV are likely to hit more home runs per fly ball.

*FB EV = Average of all exit velocities on fly balls*

Why Exit Velocity is Important – anselo13, FanGraphs Community Research

Using Fly Ball Exit Velocity – Dan Richards, RazzBall

**FB% **

Fly Ball % (FB%) measures how often a batter hits a fly ball (or pitcher induces a fly ball). While it is only one part of the equation, a high fly ball% can often be a decent indicator of a batter who hits a lot of home runs (or pitcher who gives up home runs). Additionally, even in small samples, FB% gives us a good piece of information about a player.

*FB% = Fly Balls / Batted Balls*

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Why Hitting Fly Balls are Good – Bill Brink, Pittsburgh Post-Gazette

How Fly Ball Rate is One of the Most Stable Offensive Statistics – Piper Slowinski, Fangraphs

**FIP**

Fielding Independent Pitching (FIP) is one of the most commonly used metrics to evaluate a pitcher. Theoretically, walks, strikeouts, and home runs are the only events pitchers can fully control, so they are the only factors FIP accounts for. FIP does not consider any ball in play because they are too reliant on luck and/or the defense behind a pitcher. While FIP does have some major flaws, the difference between a pitcher’s FIP and ERA can sometimes tell us if they have gotten lucky.

*FIP = (13 * HR + 3 * BB – 2 * K)/Innings Pitched + Constant*

Why FIP Should be Used More Frequently than ERA – Zach Gottschalk, Lookout Landing

Why We Should Be Cautious Using FIP – Diamond Digest

**Fl&B %**

FlB% measures how often a batted ball is classified as a flare or burner. A flare is considered a ball hit into the shallow outfield whereas a burner is a hard hit ground ball. While these are two very different types of batted balls, they tend to produce similar results, so they are categorized together. It is considered to be the second best type of contact, behind a barrel.

*Fl&B% = Flares and Burners/Batted Balls*

Intro to Ideal Contact Rate – Jonathan Metzelaar, Pitcher List

How Contact Management can be a Pitcher Skill – Craig Edwards, FanGraphs

**Foul%**

Foul% measures how often a batter hits a foul ball. While this metric doesn’t offer much in terms of player analysis, players with high foul rates are likely good at avoiding strikeouts and making the pitcher work.

*Foul % = Foul balls/Total Pitches*

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Are Foul Balls Good or Bad – Alex Chamberlain – RotoGraphs

**GB%**

Ground ball % (GB%) can be very important for both a hitter and pitcher. Most contact pitchers strive on inducing ground balls, so this metric can tell us whether to trust one who doesn’t strike a lot of batters out. For a hitter, GB% can be an indication of quality of contact, as you want to keep the ball in the air. Additionally, GB% can be reliable in small samples.

*GB% = Ground Balls/Batted Balls*

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How Ground Ball Rate is One of the Most Stable Offensive Statistics – Piper Slowinski, Fangraphs

The importance of Ground Ball Rate – Eno Sarris, The Athletic

**gLoc%**

gLoc% measures the percentage of pitches located on the pitcher’s glove side. Given a right-handed pitcher, if we were to draw an imaginary vertical line that splits the strike zone in half, gLOC% tracks the portion of pitches that land to the left of the line (and vice versa for a lefty). The height and strike zone status are irrelevant.

*gLOC% = Pitches located on pitcher’s glove side/pitches thrown*

How pitch location impacts batted balls – Jonah Pemstein, FanGraphs

The importance of pitch location – Patrick Brennan

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**H/9**

H/9 measures how often a pitcher allows a hit. It is scaled to indicate how many hits the pitcher would give up in a nine-inning game. While hits can often be a result of bad luck, H/9 is one of the most commonly used metrics to evaluate a pitchers results.

*H/9 = (Hits Allowed/Innings Pitched)*9*

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Why We shouldn’t Use “Per Nine” Metric – James Gentile, Beyond the Box Score

**heLoc% **

heLoc% measures the percentage of pitches located in the middle of the strike zone. If we were to divide the strike zone into a 3×3 grid, heLoc% would determine what proportion of pitches were thrown in the middle square. This zone is the most dangerous, as it produces the best results for batters. Thus, pitchers generally want to avoid having a high heLoc%.

*heLOC% = Pitches located middle-middle / pitches thrown*

How pitch location impacts batted balls – Jonah Pemstein, FanGraphs

The importance of pitch location – Patrick Brennan

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**HH%**

Hard hit % (HH%) is one of the simplest, yet most effective, quality of contact metrics out there. It simply tells us how often the batter hits the ball hard (or pitcher induces hard contact). “Hard contact” is defined by any batted ball with an exit velocity of 95 MPH or higher. If a batter has a high HH% but isn’t seeing great results, it could be a sign of positive regression in the future.

*HH % = (Batted balls with >= 95 MPH EV)/Batted Balls*

Importance of Hard Hit Rate – Bobby Mueller, FanGraphs Community Research

Introduction to Dynamic Hard Hit Rate – Connor Kurcon, Six Man Rotation

How different Statcast Measures correlate with Power Metrics– Al Melichor, FanGraphs

**hiLoc%**

hiLoc% measures the percentage of pitches located high to the batter. This accounts for all pitches that are above the strike zone, regardless of horizontal location. The result of the pitch does not matter when calculating this metric, just the location.

*hiLoc% = (Pitches Thrown high to the batter)/Pitches Thrown*

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How pitch location impacts batted balls – Jonah Pemstein, FanGraphs

The importance of pitch location – Patrick Brennan

**HR/FB%**

HR/FB% measures the rate of fly balls that end up as home runs. While pitchers have some control over distance of fly balls induced, HR/FB% can sometimes determine how lucky a pitcher has gotten. For batters, the best power hitters typically have the highest HR/FB rates.

*HR/FB% = Home Runs/Fly Balls*

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Evaluating Hitters Using Long Fly Ball Rate – Matt Wallach, Pitcher List

How different Statcast metrics correlate with HR/FB – Al Melichor, FanGraphs

How To Use HR/FB Rate with Pitchers – Kreighton R, Wager Bop

**ICR%**

Ideal Contact Rate (ICR%) is a metric that combines many important contact metrics (barrel%, solid contact%, and flare/burner%) into one. It essentially tells us how often a batter made “good” contact on the ball. The actual result of the play is irrelevant, just the quality of contact.

*ICR% = (Barrels + Solid Contact + Flares/Burners)/Batted Balls*

Intro to Ideal Contact Rate – Jonathan Metzelaar, Pitcher List

**IFFB%**

Infield Fly Ball Percentage tells us what portion of a hitter’s fly balls end up staying in the infield. Since infield fly balls are almost always outs, batters strive to keep this number as low as possible. Naturally, pitchers want to keep this number as high as possible.

*IFFB% = Infield Fly Balls/Fly Balls*

The Effect of Infield Fly Balls – Devan Fink, Beyond the Box Score

Batter Traits that Cause Infield Fly Balls – Jeff Zimmerman, FanGraphs

**iLOC%**

iLoc% measures the percentage of pitches located inside to the batter. This accounts for all pitches that are off the plate on the inside, regardless of vertical location. The result of the pitch does not matter when calculating this metric, just the location.

*iLoc% = (Pitches Thrown inside to the batter)/Pitches Thrown*

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How pitch location impacts batted balls – Jonah Pemstein, FanGraphs

The importance of pitch location – Patrick Brennan

**IPA%**

Ideal Plate Appearance (IPA%) is a metric that combines many important contact metrics (barrel%, solid contact%, and flare/burner%) into one. It essentially tells us how often a batter made “good” contact on the ball. However, instead of measuring this out of all batted balls, it is out of all plate appearances, so walks and strikeouts are included in the formula.

*IPA% = (Barrels + Solid Contact + Flares/Burners)/Plate Appearances*

Intro to Ideal Contact Rate – Jonathan Metzelaar, Pitcher List

**K%**

Strikeout rate (K%) is the proportion of plate appearances that end in a strikeout. It can be used as either a hitter or a pitcher stat. A hitter with a low strikeout rate likely has a great contact skill, whereas a pitcher with a high strikeout rate likely has great command and/or putaway stuff.

*K% = Strikeouts / Plate Appearances*

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A Beginner’s Guide to Plate Discipline Metrics – Dave Cherman, Pitcher List

How Strikeout Rate is One of the Most Stable Offensive Statistics – Piper Slowinski, Fangraphs

**LA**

Each time the batter hits the ball, their launch angle (LA) is measured as the angle the ball makes with the horizon directly after contact. When you see it on a player page, LA represents a hitter’s (or pitcher’s) average launch velocity on all batted balls. Launch angle is a decent measure type of contact, as fly balls and line drives lead to the best results

What is Launch Angle and Why Does it Matter? – Evan Altman, Cubs Insider

**LD%**

Line Drive % (LD%) measures how often a batter hits a line drive (or pitcher induces a line drive). Line Drives are the best type of batted balls at producing hits. However, since it takes a while to stabilize, we typically need a large sample size in order to tell if an increase in a batter’s LD% is significant.

*LD% = Line Drives/Batted Balls*

Why LD% Can Be Driven By Luck – Rick Lucks, Roto Baller

**LOB%**

Left on base % (LOB%) tells us how often a pitcher allows a base runner to score. LOB% can be a symbol of luck, as a high LOB% may imply the pitcher still allows a lot of base runners. However, over a large enough sample, LOB% may give us an indication of how good a pitcher is at working out of jams.

*LOB% = 1 – (Runs Allowed / Base Runners Allowed)*

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The Importance of LOB% – Alex Skillin, Beyond the Box Score

**loLoc%**

loLoc% measures the percentage of pitches located low to the batter. This accounts for all pitches that are below the strike zone, regardless of horizontal location. The result of the pitch does not matter when calculating this metric, just the location.

*loLoc% = (Pitches Thrown low to the batter)/Pitches Thrown*

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How pitch location impacts batted balls – Jonah Pemstein, FanGraphs

The importance of pitch location – Patrick Brennan

**Max EV**

Each time the batter hits the ball, their exit velocity is measured as the speed of the ball directly after contact. Max EV measures the highest recorded exit velocity for a batter in a given season. Max EV actually has a very strong correlation with future results in power related metrics

*MAX EV = Maximum Exit Velocity of all Batted Balls*

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The Relevance of Max EV – Alex Chamberlain, RotoGraphs

**Non-BIP Strike%**

Typically, any database that tracks “Strike%” will included a ball in play as a strike. However, Non-BIP Strike% does not. It is very similar to CSW%, and has similar results and use, but it also counts foul balls as a strike

*Non-BIP Strike% = (Whiffs + Called Strikes + Foul Balls)/Total Pitches*

**O-Con%**

O-Contact % (O-Con %) measures a batter’s (or pitcher’s) contact rate on pitches out of the strike zone. A foul ball still counts as contact (a foul tip does not). O-Contact rate is the exact O-Whiff Rate

*O-Con % = (Swings – Whiffs)/Swings ***Only on pitches out of the zone*

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A Beginner’s Guide to Plate Discipline Metrics – Dave Cherman, Pitcher List

**O-Swing%**

O-Swing%, which is also known as Chase Rate measures the proportion of pitches out of the zone the batter swings as (or pitcher induces a swing). It is one of the best plate discipline metrics out there, as batters strive not to swing at pitches out of the zone. It additionally, has a very strong correlation with future plate-discipline related results, even in small sample sizes.

*O-Swing% = Swings/Total Pitches ***Only on Pitches out of the zone*

How O-Swing% is One of the Most Stable Offensive Statistics – Piper Slowinski, Fangraphs

A Beginner’s Guide to Plate Discipline Metrics – Dave Cherman, Pitcher List

**oLoc%**

iLoc% measures the percentage of pitches located outside to the batter. This accounts for all pitches that are off the plate on the outside, regardless of vertical location. The result of the pitch does not matter when calculating this metric, just the location.

*oLoc% = (Pitches Thrown outside to the batter)/Pitches Thrown*

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How pitch location impacts batted balls – Jonah Pemstein, FanGraphs

The importance of pitch location – Patrick Brennan

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**Oppo%**

Oppo % measures the proportion of batted balls that are hit to the opposite field. Each batted ball is placed in one of three categories: pull, opposite field, or center. Oppo% gives us the percentage that was classified as opposite field, generally towards right field for a right-handed batter(or vice versa)

*Oppo % = Opposite Field BIP / BIP*

The importance of Spray Angle – Nick Gerli, Pitcher List

**OPS**

OPS is a popular stat that combines two other useful ones: On Base Percentage and Slugging Percentage. While it doesn’t make a ton of sense mathematically, it correlates well with many other important offensive metrics. OPS is a simple way to evaluate a hitter’s performance over a given season, but does not hold much predictive value.

*OPS = On Base Percentage + Slugging Percentage*

The importance of OPS – Courtney Perigo, Towards Data Science

The flaws of OPS – Bryan Grosnick, Beyond the Box Score

**PAR%**

Putaway Rate (PAR%) tells us how successful a given pitch is with two strikes. It measures how often the pitch results in a strikeout when used in 2 strike counts. Pitchers with at least one pitch that has a high PAR% are likely dangerous to fall behind to.

*PAR% = (Called Strike + Whiffs)/Pitches ***2-strike counts only*

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Why You Should Care About Putaway Rate – Alex Fast, Pitcher List

**Pull%**

Pull % measures the proportion of batted balls that are hit to the opposite field. Each batted ball is placed in one of three categories: pull, opposite field, or center. Pull% gives us the percentage that was classified as a pull, generally towards left field for a right-handed batter(or vice versa)

*Pull % = Pull BIP / BIP*

The importance of Spray Angle – Nick Gerli, Pitcher List

The Pros And Cons of Pulling the Ball – Dominikk85, FanGraphs Community Research

**QS**

A quality start (QS) is defined when the starting pitcher throws at least six innings while allowing three earned runs or fewer. The outcome of the game is irrelevant. While this stat is somewhat subjective, it is a better results-related metric than relying on pitcher wins. It can often be used as a category in fantasy baseball leagues.

**Secondary %**

Secondary % measures how often a pitcher turns to non-fastballs. Statcast classifies a 4-seamer, cutter, and sinker as a fastball. While this does not give us any indication of the pitcher’s value, it provides an important piece of information about their repertoire.

*Secondary % = (Total Pitches – Fastballs)/Total Pitches*

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Performance by Different Pitch Types – Nick Gerli, Pitcher List

Fastballs Are Becoming More Rare – Ben Clemens, FanGraphs

**SLG**

Slugging percentage is one of the most common metrics used to evaluate a batter’s power. It measures the hitter’s total bases per at bat, meaning a home run, triple, double, and single are worth 4, 3, 2, and 1 point respectively. Like batting average Slugging percentage has many flaws, at it doesn’t necessarily encapsulate the actual value of these hits, and holds little to no predictive value.

*SLG = (4 HR + 33B + 2*2B + 1B)/AB*

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The Flaws of Slugging Percentage – Douglas VanDerwerken, Taylor & Francis Online

**Solid %**

Statcast classifies each batted ball into one of six categories based on its exit velocity and launch angle: Barrel, Solid Contact, Flares/Burners, Topped, Under, and Weak. Solid % measures the proportion of those classified as Solid contact. Generally, solid contact is a ball hit in the air with a decent likelihood of an extra-base hit, but does not quite reach the requirements of a barrel.

*Solid % = (Solid Contact)/Batted Balls*

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Intro to Ideal Contact Rate – Jonathan Metzelaar, Pitcher List

How Contact Management can be a Pitcher Skill – Craig Edwards, FanGraphs

**Spin**

Statcast calculates a spin rate on every pitch delivered by a pitcher. When seen on the stats page, Spin measures the pitcher’s average spin rate on a given pitch. On certain pitches, such as 4-seam fastballs, many pitchers strive to have high spin rates, as it can lead to higher velocity and better movement. However, in other pitches, such as splitters, high spin may not be as good.

*Spin = Average Spin Rate measured in revolutions per minute*

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Intro to Spin Rate – Andrea, Scout Girl Report

What we Know About Spin Rate – Jeff Long, Baseball Prospectus

Deep Dive into Fastball Spin Rate – Driveline

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**SS%**

Each time the batter hits the ball, their launch angle is measured as the angle the ball makes with the horizon directly after contact. Statcast defines the sweet spot as any batted ball hit between 8 and 32 degrees of launch angle. This range produces the highest probability of a hit and highest wOBA. While exit velocity does matter a lot, this is the most ideal launch angle.

*Sweet Spot % = [Batted Balls with a launch above above 8 degrees and below 32 degrees] / Total Batted Balls*

Intro to the Sweet Spot – Ben Clemens, FanGraphs

**Strike%**

Strike% simply tells us how often a pitcher throws a strike. A called strike, swinging strike, foul ball, or ball in play counts as a strike in this metric. While this stat is pretty simple, it is both less sustainable and less indictive of a pitcher’s ability than similar metrics like Non-BIP Strike% and CSW%

*Strike% = (Whiffs + Called Strikes + Foul Balls + Balls In Play)/Total Pitches*

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Why CSW is more important than Strike % – Alex Fast, Pitcher List

**Swing%**

Swing% tells us how often the batter swings at a pitch (or pitcher induces a swing). While it likely needs to be combined with a different metric in order to indicate how valuable a player is, it can give us an interesting piece of information about their approach at the plate.

*Swing % = Swings / Total Pitches*

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Swinging at the First Pitch – James Gentile, FanGraphs

The Importance of the Count – Stanley M. Katz, SABR

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**SwStr% **

** **Swinging Strike% tells us how often a pitch results in a whiff. This can be a very valuable piece of information for both a batter and pitcher. It correlates fairly strongly with plate discipline metrics such as strikeout rate, so it has predictive influence.

*SwStr% = Whiffs/Total Pitches*

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A Beginner’s Guide to Plate Discipline Metrics – Dave Cherman, Pitcher List

Why Swinging Strikes Are Important for Pitching – Spencer Etsey, Breaking Blue

*(Photo by Kyle Ross/Icon Sportswire)*

I used OPS+ a lot last year putting together my Fantasy teams. This year so far I am having trouble finding a list of last year’s OPS+ leaders.