An “easy” look at some sabermetrics terms and what they mean.
Back in the “old days” of baseball, maybe before the 1980s, just about any everyday baseball fan could measure a hitter’s or pitcher’s performance over a season or by career by the standard stats:
- For pitchers, it was earned run average (ERA), strikeouts (Ks) and wins and losses (“15-5”)
- For batters, it boiled down to batting average, home runs, runs batted in (RBIs) and, for non-power hitters, hits. Those stats remain relevant.
That was then; this is now. The thinking is that the old numbers don’t paint an accurate picture. Statisticians these days in baseball use formulas (and their abbreviations) from sabermetrics—Society for American Baseball Research + metrics—to measure a player’s value or efficiency. The new terms are used all the time now on sports channels such as ESPN, in podcasts and by broadcasters.
Lost in translation.
Unless you keep score during games, you may not be up to speed on many of these newer stats—what they are and what they mean. This article helps fix that by taking a look at the most used stats. With that, here’s a simple look at a handful of the terms used to analyze today’s hitters:
H = hits
BB = base on balls (walk)
HBP = hit by pitch
AB = at-bat
SF = sacrifice fly
PA = plate appearance
STAT: Isolated Power (ISO)
You want players on your team who hit doubles, triples and homers. ISO is the stat that gives you a “power number” based on extra-base hits. The players who get extra bases have a higher ISO and deliver more power than their teammates. The formula does not take singles into account! One version of Isolated Power was created by Brooklyn Dodgers owner Branch Rickey and Allan Roth, considered the first full-time MLB statistician, during the 1950s—they called it Power Average.
There are two ways to look at ISO.The formulas:
1. ISO = (1x2B + 2x3B + 3xHR) divided by at-bats
or
2. ISO = slugging percentage minus batting average
Hitters with the best Isolated Power (ISO) in 2020:
1. Juan Soto, Washington Nationals.344
2. Luke Voit, New York Yankees.333
3. Ronald Acuña Jr., Atlanta Braves.331
4. Mike Trout, L.A. Angels of Anaheim.322
The all-time career leaders in ISO:
1. Babe Ruth.348
2. Mark McGuire.325
3. Barry Bonds.309
4. Lou Gehrig.292
STAT: Slugging Percentage (SLG)
Let’s focus on hits only, and this time (unlike with ISO) we’ll take all of them into account. Singles are good, of course. A double is twice as nice, a triple three times as nice…you get the idea. So, you put a numeric value on all the singles, all the doubles, triples and homers, and add it all up. Then divide that by the total number of at-bats. (Walks and hit-by-pitches aren’t included in the at-bats.) It is actually an average of how many bases a player gets out of an at-bat when he puts the ball in play.
The formula:
(1B + 2Bx2 + 3Bx3 + HRx4)
AB
Players with the best Slugging Percentage (SLG) in 2020:
1. Juan Soto, Nationals .695
2. Freddie Freeman, Braves .640
3. Marcell Ozuna, Braves.636
4. José Abreu, Chicago White Sox.617
The all-time career leaders in SLG:
1. Babe Ruth.6897
2. Ted Williams.6338
3. Lou Gehrig.6324
4. Jimmie Fox .6093
STAT: On-Base Percentage (OBP)
A talented, savvy hitter swings a good bat, has a good eye and might let himself get hit by a pitch or two. In other words, he knows how to get on base. On-base percentage, a popular stat, is a ratio of how many times a batter gets on base to plate appearances.
Some instances of reaching base aren’t figured in, however—getting on by an error, a fielder’s choice, fielder’s obstruction, catcher’s interference, etc., don’t count. The ones that do count are hits, walks and times hit by pitch. OBP is another stat created mid–20th century by Branch Rickey and Allan Roth.
The formula: OBP =
(H + BB + HBP)
(AB + BB + HBP + SF)
Players with the best On-Base Percentage (OBP) in 2020:
1. Juan Soto, Nationals.490
2. Freddie Freeman, Braves .462
3. Marcell Ozuna, Braves.431
4. DJ LeMahieu, New York Yankees .421
The all-time career leaders in OBP:
1. Ted Williams.487
2. Babe Ruth.470
3. John McGraw.476
4. Lou Gehrig.447
STAT: On-Base Plus Slugging (OPS)
Okay. Now you know about On-Base Percentage and Slugging Percentage. Let’s add the two up to get the “On-Base Plus Slugging” number…OPS. This is a sabermetrics term that tells you how often a player is on the bases, as well as his power. A number above .900 is considered “great.”
The formula: OPS = OBP + SLG
Players with the best On-Base Plus Slugging (OPS) in 2020:
1. Juan Soto, Nationals1.185
2. Freddie Freeman, Braves1.102
3. Marcell Ozuna, Braves1.067
4. DJ LeMahieu, Yankees1.011
Here are all-the time career leaders for OPS:
1. Babe Ruth1.164
2. Ted Williams1.115
3. Lou Gehrig1.079
4. Barry Bonds1.051
STAT: Batting Average on Balls in Play (BABIP)
A manager wants hitters who can put the bat on the ball and put the ball in play. That’s when something good can happen. BABIP answers the question, “What is the hitter’s average over a full season when he actually puts the ball in play?”
It also measures how “lucky” a batter can get, how much his speed affects his ability to get on base and how efficient he is at getting on base when he makes contact.
The BABIP stats numbers don’t include sacrifice bunts, hit-by-pitches, strikeouts, home runs and walks. So, if a hitter goes two-for-six with a home run and a strikeout, his regular average for that day would be .333, but his BABIP would be .250 because the home run and walk wouldn’t be counted in the at-bats—he was one-for-four as far as BABIP is concerned. A BABIP of .400 is considered great.
The formula: BAPIP =
(H – HR)
(AB – K – HR + SF)
Players with the best Batting Average on Balls in Play (BABIP) in 2020:
1. Michael Conforto, Mets.412
2. Donovan Solano, Giants.396
3. Raimel Tapia, Rockies.392
4. Marcel Ozuna, Braves.391
Here are the highest recorded BABIP in a season over the past 75 years:
1. Rod Carew (1977).408
2. José Hernández (2002) .422
3. Manny Ramírez (2000).403
4. Roberto Clemente (1967).403
5. Ichiro Suzuki (2004).399
RESOURCES: m.mlb.com/glossary/standard-stats/on-base-percentage; mlb.com/stats/pitching/babip; m.mlb.com/glossary/advanced-stats/isolated-power#:~:text=Definition,200; library.fangraphs.com/pitching/lob; library.fangraphs.com/pitching/fip; m.mlb.com/glossary/standard-stats/slugging-percentage; m.mlb.com/glossary/standard-stats/walks-and-hits-per-inning-pitched; sportingnews.com/us/mlb/what-is-fip; insiderbaseball.com/blog_introduction_rate_lob; statliners.com/2014/09/27/babip-batting-average-balls-play; baseballessential.com/news/ -obp-and-slg; baseball-almanac.com/hitting/hiisolpow1.shtml
Photo credit: Chris Humphreys-USA TODAY Sports
