Sabermetrics for Beginners: The Slash Line

After talking with a friend over the past week about this sabermetrics series, I realized that going over a term called the "slash line" is a must to cover towards the beginning of these articles. The slash line consists of batting average (AVG), on-base percentage (OBP), and slugging percentage (SLG)

Batting Average (AVG)

Batting average is calculated by the total number of hits divided by the total number of at-bats a player has throughout a season, career, or any other customized time period. An at-bat accounts for any ball put in play in the field or a strikeout, so walks, intentional walks, and hit by pitches are not included when calculating batting average. These metrics are seen out of the hitter's control when a pitcher walks or hits them, so they are left out of the equation.

Batting average is a ratio that is measured on a scale from 0.000 to 1.000. Three decimal points are important to include as throughout the season the typical Major League starter gets around 550 plus at-bats. So, when determining rankings and analyzing players' performances, expanding to a third decimal point allows for a better picture of their true batting average.

Notably, of the top 20 hitters who have the highest career batting averages, 14 out of 20 (70%) of them are left-handed batters. Also, it is widely considered in baseball that batting around .300 will put you up there with the all-time greats and Hall of Famers. While only succeeding three times out of ten in other walks of life might signal the need of rapid, drastic improvement, a failed test, or a scolding from a boss or manager, in baseball it can make the player millions of dollars and showcase their hitting ability to be consistent throughout their career.

On-Base Percentage (OBP%)

On-base percentage is a statistical ratio that aims to showcase the ability of a hitter to get on any of first, second, third base or to home plate as result from putting the ball in play. The total number of hits plus the total number of walks and hit by pitches is divided by the total number of plate appearances (total at-bats plus walks, hit by pitches, and sacrifice flies).

OBP is measured on the same scale as batting average, but is often anywhere from .001 to around .100 higher because in taking account the amount of times the hitter gets on base from a walk of hit by pitch, that results in the higher ratio of OBP to than that of what the batting average ratio is.

According to Baseball Reference, Ted Williams has the highest career on-base percentage of .482, while his career batting average was .344. This .138 value difference highlights the patience Williams possessed in the batter's box to draw walks and find a way at any means possible to get on-base for the batters behind him to score him.

Slugging Percentage (SLG%)

Finally, slugging percentage is a statistic that attempts to showcase the hitter's power of driving the ball to the gaps in the outfield for extra bases or over the fence for a home run, which is then divided by the total number of at-bats. Each base the hitter gets to is given a value, 1 to singles, 2 to doubles, 3 to triples, and 4 to home runs. The total amount of each hit is then multiplied by each of their respective values to get the number of total bases (TB). This value is then divided over their total number of at-bats to get the slugging percentage value.

Baseball legend and Hall of Famer Babe Ruth holds the all-time record for slugging percentage with an outrageous .690, which is .057 higher than Ted Williams, who has a .633 SLG%. Home runs and hard hit doubles and triples are some of the most exciting plays to happen in each to get the crowd roaring as they see the players run around the bases and score runs. This becomes evident by the fact that Babe Ruth and Ted Williams were two of the early pioneers who made this sport popular and exciting to watch with their ability to produce runs and hit majestic home runs.

While slugging percentage has lost popularity in recent years due to the creation of on-base + slugging percentage (OPS) and other modern statistics that better encapsulate a hitter's performance, SLG% remains a simple statistic to calculate to measure a hitter's productivity from the batter's box.

Closing Thoughts

The slash line is often one of the most viewed group of statistics that is viewed by players, coaches, fans, and parents across all ages and levels of baseball. Its relative ease of calculating is why it's at the forefront when players first begin to assess their performance and what coaches can use as a baseline to compare and contrast different players.