Slugging
What's the difference between slugging and batting average?
Batting average counts hits, slugging counts total bases. That one change makes slugging the better power stat, though neither tells the whole story.
By Artifact Editors, Editorial team
Published · 3 min read
In this article
How each stat is calculated
The bottom line: batting average tells you how often a hitter gets a hit, and slugging tells you how many bases those hits are worth. Batting average is hits divided by at-bats. Slugging is total bases divided by at-bats, where a single is one base, a double is two, a triple is three, and a home run is four.
The formulas are laid out in the methods section of an NCAA softball study. We could not fetch an official MLB glossary entry, but the definitions match across the academic sources we reviewed.
Why slugging measures power better
The bottom line: slugging is the better power stat because it counts extra bases. Batting average treats a bloop single the same as a 450-foot home run. Slugging catches that difference.
Subtract batting average from slugging and you get isolated power, which shows how much of a hitter's production comes from extra-base hits instead of singles. A study on athletic intelligence and baseball performance uses this definition directly.
What the run-scoring numbers say
The bottom line: slugging explains more of run scoring than batting average does, but the exact figures depend on which estimate you trust. The softball paper's literature review puts batting average alone at about 66% of the variation in runs scored, slugging at about 82%, and OPS at about 91%. Those figures are secondhand, and we could not retrieve the original study they draw on.
A second set of figures in the same excerpt gives 0.83 for slugging and 0.90 for OPS, which does not match the first set. Treat the precise values as rough until someone checks the original work. The direction of the result is consistent across both sets.
A related line of work by Hakes and Sauer, which we could only see secondhand through a golden ratio study of baseball winning percentages, argues that slugging and on-base percentage account for most of the variance in team winning percentage. Their reference is listed inconsistently across papers, so verify it before citing.
What neither stat tells you
The bottom line: neither stat counts walks or hit-by-pitch, and both depend partly on the defense. Whether a ball in play becomes an out is outside the hitter's control. Plate-discipline researchers argue that this makes both stats noisier measures of skill, as laid out in a study on visual function and batting.
Slugging ignores walks entirely. A reinforcement-learning preprint on pitcher decision-making calls slugging and OPS incomplete rewards for hitting, but it is a lower-tier source and should be read that way.
The softball review also reports, secondhand, that batting average, isolated power and plate discipline are relatively independent of one another, while slugging and on-base percentage are highly correlated.
Which one to use
The bottom line: do not rely on batting average alone. Read slugging alongside on-base percentage, or use OPS, which combines the two. The table below sets the stats side by side.
| Stat | Formula | Credits walks? | What it rewards |
|---|---|---|---|
| Batting average | Hits / at-bats | No | Frequency of contact |
| Slugging | Total bases / at-bats | No | Power and extra-base hits |
| OPS | On-base percentage + slugging | Yes, through OBP | Combined offensive production |
For more on how the stat is used in practice, see our slugging coverage.
Frequently asked questions
Is a high slugging percentage better than a high batting average?
Not always. A high slugging percentage suggests a hitter produces many total bases and extra-base hits, which the research links to run scoring. A high batting average shows frequent contact. Look at both alongside on-base percentage, since neither captures walks.
What is isolated power?
Isolated power is slugging percentage minus batting average. It shows how much of a hitter's production comes from extra-base hits rather than singles. Because it strips out singles, it is a quick check on raw power.
Does OPS fix the problem?
Partly. OPS adds on-base percentage to slugging, so it credits walks and hit-by-pitch. The research we reviewed treats it as a stronger run-scoring predictor than either stat alone, but it is still a summary, not a full picture of offense.
Sources (6)
- Head Coach Gender and Player Performance in NCAA Softball PMC
- Head Coach Gender and Player Performance in NCAA Softball, Table 1 and methods section same article as 1; cited separately for the Scully formula
- The Athletic Intelligence Quotient and Performance Outcomes in Professional Baseball PMC
- The Effect of Visual Function on the Batting Performance of Professional Baseball Players PMC
- The golden ratio in baseball: the influence of historical eras on winning percentages in major league baseball PMC
- MONEYBaRL: Exploiting pitcher decision-making using Reinforcement Learning arXiv preprint, lower evidence tier
