Tuesday, May 24, 2011

Is Batting Average Really As Important As It's Made Out to Be?

At the beginning of every Major League Baseball game a series of stats flash across the screen; who will be playing where on the field, who the pitchers are and the line-up. Next to each players name in the line-up is a little three digit number that is supposed to be the most important number to any baseball player, his batting average. Does a .248 batting average really mean your shortstop is struggling at the plate, or is there a better set of stats you could look at to determine the future of your team?

The frequency that MLB telecasts and radio broadcasts rattle off a players batting average assigns that number more credit than it is actually due, a players batting average does not accurately depict how well he is performing. The best number that a person could look at is a players On-Base Percentage.

A players on-base percentage, OBP, accounts for every at bat that he takes, including every time that he draws a base-on-balls or reaches on a hit-by-pitch.Whereas in the calculations for a players batting average anything that is not a hit or an out is discarded and does not factor into the rating of the player.

For example, as of Tuesday, May 25, 2011, Detroit Tigers shortstop Jhonny Peralta had a .296 batting average, leading one to believe that he is not having the easiest of time at the plate. But Peralta's OBP tells a different story, at .359 Peralta is on base more than any other Tiger with the exception of Miguel Cabrera.

Calculating a player's OBP is quite easy, but somewhat time consuming. The name "on-base percentage" confuses people, as it is not out of 100, but out of 1,000. A perfect OBP is 1.000, or a thousand. To find a player's OBP just;
  1. Add up all of the player's plate appearances
  2. Subtract the number of sacrifice bunts the player has made, this will give you the total at bats
  3. Add up all the times the player reached base; either a hit, base on balls, hit-by-pitch. This does not include errors by fielders or fielders-choice plays.
  4. Divide the times the player reached base safely by the total
  5. This way of thinking and scoring baseball is known as sabermetrics, or SABR 
  6. Round to the third decimal point; .52001 is .520
By knowing the player's OBP one can more accurately predict the probability of the player reaching base safely than trying to glean that information from a batting average.

A perfect OBP does not mean that a team would score infinite runs as one might assume, but a team could have a perfect OBP while scoring only one run. The leadoff batter could hit a home run, then the next three batters could fly out to the outfielders; the team will have gained four runs for the inning. The team will come away from the inning with a perfect OBP but only one run.

The weight that is placed upon RBI's is also one that is undeserved; the act of getting an RBI requires a significant amount of luck. For example, a batter who is routinely batted third should have many more RBI's than a player who bats leadoff. Is that an indication of the former player's superiority? No, it is simply that the batter hitting third should be put in situations where there are runners on base; if there are no runners the batter cannot get an RBI. This puts a bit of luck whether or not a player will be put into an RBI situation, making the RBI less valuable as a statistic.

Instead one should focus more on the slugging percentage of a player, this stat shows you the power that a player has. It takes into account the total bases that a player has gotten on every hit throughout the season. For example a single counts a one base, but a homer counts as four. Slugging percentage is calculated per 4,000 meaning that a perfect slugging percentage would be 4.000.

To figure out a player's slugging percentage one must;
  1. Add up all official at bats. Do not include at bats that resulted in a base on balls, sacrifice or hit by pitch.
  2. Add up total bases. One for a single, two for a double, etc.
  3. Divide total bases by total at bats.
  4. Round to the third decimal point. .5671 is .567
  To figure out if your shortstop is worth keeping or bound for the waiver wire, look at his OBP and slugging percentages instead of his batting average and RBI's. By doing this, you will get a more complete picture of your shortstop and will better be able to assess his abilities for your team.

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