Baseball stats used to be simple enough for even the most casual viewer to digest.
On the back of every baseball card, a player’s offensive contributions were summarized by a statline featuring the same major categories: games, batting average, home runs, RBI, runs, and stolen bases. These basic counting stats helped shape baseball discourse for decades, until the sabermetric revolution rendered them insufficient and outdated.
To fully grasp the intricacies of today’s data-driven game, fans need to be familiar with analytics that offer a more comprehensive understanding of both individual and team performance. Below are the most important stats for evaluating offense in modern baseball.
Hard-hit rate
Statcast defines a “hard-hit ball” as a ball that leaves the bat with a velocity of 95 miles-per-hour or greater. Thus, a player’s hard-hit rate is calculated by dividing his number of hard-hit balls by his total number of batted balls.
Although batting average was once considered the best way to measure a hitter’s consistency, batting averages are often skewed by factors beyond a hitter’s control. For example, a batter may be hitting line drives on a consistent basis, but if the majority of those liners are being caught, his average will be negatively affected.
Hard-hit rate allows us to determine which hitters are routinely producing quality at-bats based on quality of contact.
O-Swing %
Nearly all major league pitchers feature an assortment of wipeout breaking pitches in their repertoire. A pitch that a batter initially registers as a fastball can break sharply at the last second. Batters that resist the temptation to chase pitches outside the strike zone have a greater chance of reaching base and winning the one-on-one battle against the pitcher.
O-Swing % (outside swing percentage) calculates the percentage of pitches that a batter swings at outside the strike zone. This stat is instructive because it demonstrates which batters possess the best pitch recognition. A batter with a low O-Swing % (like Alex Bregman) resists the temptation to chase pitches that will likely result in outs.
OPS+
OPS (On-base percentage plus slugging percentage) is often presented as the single stat that best encapsulates a hitter’s overall performance. However, while OPS is a useful metric, it also has its limitations.
Adjusted OPS, or OPS+, provides a more accurate measurement of offensive production by normalizing an individual player’s OPS across the league and accounting for external factors like ballpark.
An OPS+ of 100 is league average, and each point above or below that mark is a percentage point above or below the league average. This means that a player with an OPS+ of 130 has an OPS that is thirty percent better than league average.
Adjusted OPS is helpful because not all ballparks are created equal. A player has a better chance of posting a .900 OPS if he plays his home games at Yankee Stadium rather than Citi Field, a fact that OPS+ takes into consideration.
The stat is also useful for Hall of Fame discussions because it puts a player’s OPS into proper historical context. For instance, though Tony Gwynn’s .786 OPS in 1992 may seem pedestrian by today’s standards, his 121 OPS+ tells us that it was 21 percent better than the league average that season.
wRC+
Weighted Runs Created Plus (wRC+) measures a player’s offensive value in terms of the number of runs he helps produce. The stat properly weighs the value of each offensive outcome (ie. single, double) rather than treating all hits or times on base equally.
Just like OPS+, wRC+ is scaled so that league average is 100 and each point up or down is a percentage point above or below league average. It is also similar to OPS+ in that it accounts for park effects and the league’s run-scoring environment. According to Fangraphs, a wRC+ of 140 is great, while a wRC+ of 160 is considered excellent.
The park and league adjustments of wRC+ make it exceptionally useful for comparing players from different eras, as well as players that play in ballparks with vastly different dimensions.
