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Calculating EAV | On Base Plus Slugging EAV | Cross Era Evaluations | Sabermetrics

[Photos left to right : Roger Connor, Babe Ruth, Ted Williams, and Hank Aaron]

How To Determine Era Adjusted Value.

Basically, Era Adjusted Value [called EAV in an abbreviated form] is a relative baseball batting statistic currently in development.

Simply, you first determine a ball players's on base percentage, his slugging percentage, and the combination of the previous two equations through addition called On Base Plus Slugging. Then you calculate the league's on base percentage, slugging average, and ops. Then divide the the player's stat into the league stat [with the ob%, slg%, and ops]. Finally, you leaf through a book or surf the internet, or get a fancy computer program to determine the player's home ballpark value, and finally divide the already relative value by the ballpark factor. In order to display longivity, players must have at least 5,000+ plate appearances to qualify for this stat.

example : Dick Allen

381 OB% + 534 SLG%= .915 OPS

The league average during his career was 356 OB% + 346 SLG%=.702

Ballpark adjustment=100.133

OB EAV=107.222 [106.880 w/ballpark adjustment]
SLG EAV=154.335 [154.130 w/ballpark adjustment]
OPS EAV=130.342 [130.169 w/ballpark adjustment]

An above average EAV is over 100.000, while below average is .999 and below. These numbers represent the percentage above or below the league average.

Why Era Adjusted Value?

While EAV does not particularly determine the best hitters ever,it documents the most dominent hitters of their era because of the relative equations. Individual numbers independent of EAV can document whether a player is good or not when he competes merely against himself. The problem of looking at stats in this one-dimensional form is that it only tells half the story. By using relative stats, such as EAV, you observe a more accurate dimension as players are not only competing against themselves individualy, but are also competing against other players, which in turn shows their worth instead of mere individual statistics.

Talent vs. Value.

While it is definately an asset for a ball player to display his individual skills, that is simply not a complete way to examine the player. He is merely competing against hiself. When you compare statistics in this form, it can be very misleading for various reasons. Other ballplayers may be having better careers on paper, but that is independent of the non-relative stats, therefore missing the complete picture. In short, this is called talent.

A three dimensional view of measuring stats is by dividing them by the league average. You compete against other player's statistics, which in turn shows the players net measurement instead of raw talent. This is a much more important measuring stick because it is actual competition against each other versus competition against the individual, who in turn has his stats posted of individuals competing with themselves than against each other. In short, value is much more important than talent because it is value that precisely documents who are the better players, while talent shows how good an individual player is while not taking into account the players he is competing against. In the long term, value equals wins.