Sunday, April 8, 2012

Taking Some Mystery Out Of Baseball Statistics

Welcome to Blog Entry #70.

A shout to all who are following my blog. Many sincere thanks!

This will probably be my first anniversary post, even though it is still about a week away. I started this blog on April 16, 2011.

If you have any math or calculator questions, please feel free to leave a comment - I will do my best to answer it. Maybe your question becomes a future blog entry. Thanks!




Today's blog entry will cover baseball statistics. Any one who follows baseball, especially in America, will hear tons of statistics for each player, for every single kind of situation possible. I guess this is how a lot of people keep busy watching the sport.

I am going to go over some of the more common statistics. Apparently the only thing complex about statistics is the amount of statistics and abbreviations and not the mathematics itself.

Baseball Stats

BA: Batting Average

BA = H / AB

The higher, the better.


H = the number of hits a player makes. This is each time a player successfully reaches at least one base after hitting a pitch.

AB = number of at-bats, the number of the times a player appears in front of a pitcher. However an at-bat does not include situations when the batter walks (receives four pitches deemed to be "balls"), the batter is hit by a pitch, or hits a sacrifice (intentionally bats out to get a teammate to score a run).

Examples:
Note: All examples use statistics from the 2011 season - provided by MLB and ESPN. All calculations result in three decimal places.

Matt Kemp, Los Angeles Dodgers: 195 hits in 602 at bats
BA = 195 / 602 = .324

Evan Longoria, Tampa Bay Rays: 118 hits in 483 at bats
BA = 118 / 483 = .244

SLG: Slugging Percentage

SLG = TB / AB = (singles + 2 * doubles + 3 * triples + 4 * home runs) / AB

The higher the better.


TB = total bases, a weighted sum of hits

Matt Kemp: 353 total bases in 602 at bats
SLG = 353 / 602 = .586

Evan Longoria: 239 total bases in 483 at bats
SLG = 239 / 483 = .495

ERA: Earned Run Average

ERA = 9 * ER / IP

The lower, the better.


ER = earned runs scored, in this case, by the opponent. This does not include any runs scored by "errors".

IP = innings pitched. Innings are counted by outs. So if a pitcher threw for six innings and got two outs in the seventh inning, the pitcher has pitched for 6 2/3 innings.

Caution: For IP, some statisticians use shortcut notation. For an IP listed as n.1, it means n and 1/3 innings. (n is a number). If the IP is listed as n.2, it means n and 2/3 innings. Example: A listed IP of 233.1, it means 233 1/3.

Clayton Kershaw, Cy Young Award Winner, Los Angeles Dodgers: 59 earned runs allowed in 233 1/3 innings pitched.
ERA = 9 * 59 / (233 1/3) = 2.276

Chris Carpenter of the 2011 World Series Champions St. Louis Cardinals: 91 earned runs in 237 1/3 innings pitched.
ERA = 9 * 91 / (237 1/3) = 3.451

K/9: Strikeouts Per 9 Innings Pitched

K/9 = 9 * K / IP

The higher, the better.


K = strike out. A pitcher gets this when the pitcher gets the batter to swing and miss on a pitch which results in Strike 3 (symbolized by a forward K), or the pitcher throws the ball to a batter's strike zone but the batter does nothing and is thrown out on Strike 3 (symbolized by a backwards K). Any batter who gets Strike 3 is out.

Per ESPN, Clayton Kershaw's K/9 for 2011 was 9.57 while Chris Carpenter's was 7.24. A K/9 above 9 is considered excellent.

RC: Runs Created (Bill James)

RC = (TB * (H + BB)) / (AB + BB)

The higher the better.


BB = base on balls. A BB is earned when a hitter takes a pitched deemed Ball 4 (the pitcher missed).

This is an estimate of runs created and not a count of the number of runs the player scored.

Paul Konerko, Chicago White Sox: 281 total bases, 163 hits, 77 walks in 543 at bats
RC = (281 * (163 + 77)) / (543 + 77) = 108.774 (estimated 109 runs created)

RBI: Runs Batted In

Commonly known as "ribbys", a batter gets an RBI every time the team scores a run that do not result from "errors". A batter can get up to four RBIs every time the batter is at bat.

Example: A batter has teammates at second and third base. The batter hits a double going to second base, allowing both teammates to reach home base. The batter scores 2 RBIs.

WHIP: Walks and Hits Per Innings Pitched

WHIP = (BB + H)/IP

The lower the better, real good of WHIP is below 1.


C.J. Wilson, was with the Texas Rangers in 2011, now with the Los Angeles Angels of Anaheim in 2012: 74 walks (BB), 191 hits allowed, 233 1/3 innings pitched
WHIP = (74 + 191)/(233 1/3) = 1.187


WAR: Wins Above Placement

Thankfully this is not a measurement of a baseball player's ability to use a weapon. WAR is an encompassing statistic of a player's contribution both offensively and defensively. You may have seen WAR graphs on various sports web sites. Generally, if your WAR is above 8, you are MVP material. If your WAR is around 5, you are an All-Star. If your WAR is around 2, you're an average starter. WAR at 0 and... you will most likely soon to be replaced with a minor leaguer.


These are just some of the statistics that baseball uses. Now it's time to go grab a soda and a hot dog - PLAY BALL!



Source:

MLB Clubhouse - Glossary Page

This blog is property of Edward Shore. © 2012

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