Baseball relies heavily on scouting to determine which prospects to draft in the MLB’s annual 40-round draft, and which player to sign as free agents. For many years, however, scouting methods were heavily flawed, relying on the subjective views of each individual scout (also known as “the eye test”), and traditional metrics that were broad and lacked context. Teams near the bottom of Major League Baseball’s (MLB) totem pole were looking for answers, and in 2002, the Oakland A’s and their General Manager, Billy Beane, found it.
Beane, along with current Mets GM Sandy Alderson, is credited with starting the modern sabermetrics movement, a shift that aimed to make scouting more analytically driven. This move has been made with the intent of finding more undervalued players, thereby building a more cost-effective team. These sweeping changes have helped small-market teams construct contending rosters on limited budgets, and have allowed fans, writers, and general managers alike to analyze baseball more accurately and with more detail. With that in mind, here are a few things every baseball fan needs to know about advanced analytics.
As any baseball fan will tell you, no two ballparks are the same. Some, like Coors Field, play very favorably for hitters, while others, like Marlins Park, are a pitcher’s paradise due to their exceedingly deep outfield fences. Statisticians attempt to control for such variation by introducing park factors into certain advanced metrics, which take outfield dimensions and typical atmospheric conditions into account. With traditional metrics such as batting average and home runs, a hitter who plays in Colorado (Coors Field) or Philadelphia (Citizen’s Bank Park) may have inflated numbers. With a park-adjusted number weighed against the league average, a hitter’s statistics will more accurately represent their abilities.
On-Base Plus Slugging (OPS):
Originally, baseball analysts all agreed that there were two types of hitters: contact hitters, who were known for getting on base any way they could, and power hitters, who reached base less often but could do more damage via the home run. On-base percentage (OBP) is designed to track a hitter’s ability to hit for contact, by simply taking their percentage of plate appearances that end in a hit, walk, or being hit by a pitch, and expressing it as a number between 0 and 1. Slugging percentage measures one’s ability to hit for power. By adding these two statistics together, one can gain a better understanding of a hitter’s complete skill set, rather than a single aspect. The best hitter will likely have the highest OPS, even if they don’t necessarily have the highest OBP and slugging percentage.
Fielding-Independent Pitching (FIP):
Earned run average (ERA) has been everyone’s favorite way to assess pitching performances. A pitcher’s job is to prevent runs, and that is exactly what ERA measures. However, it fails to account for the other eight players on the field. A pitcher who has a team full of Golden Glove winners behind him will almost always give up fewer runs than a pitcher of similar talent levels who is backed by slower defenders who have limited fielding range. FIP attempts to correct for that source of variability by estimating a pitcher’s run prevention if they have a league-average defense behind them.
Wins Above Replacement (WAR):
WAR is one of the most useful measurements in helping a general manager assemble the most cost-effective group of players, as it is designed to measure a player’s total contributions to his team. Individual values are calculated from the success rates of everything a player does on the field—hitting, pitching, fielding, and baserunning—and then condensed into one number. This number can be used to determine how many additional wins a player contributed for their team, as compared to a replacement-level player. Some have questioned the validity of WAR as a useful metric, because the term “replacement-level” is arbitrarily defined, but it is still a more useful tool than a statistic like batting average, which does not represent the bigger picture of a player’s abilities.
What it all means:
Sabermetric analysis is a powerful but nonetheless limited way of tracking production in baseball that allows for a more complete understanding of the game. It will never be perfect, but as statisticians find more and more ways to quantify on-field performance, these metrics will gain predictive value, as they will have controlled for other sources of variation that influence more traditional measurements. Anyone who wants to learn more about analytics in baseball is encouraged to visit the Fangraphs Library, an online encyclopedia of Sabermetric statistics.