Glossary of Terms

[Zep]

C & P'd from below

Statcorner Glossary

FanGraphs Glossary

Courtesy of the links above:

BABIP - Batting Average on balls put into play. A pitcher's average on batted balls ending a plate appearance, excluding home runs. Based on the research of Voros McCracken and others, BABIP is mostly a function of a pitcher's defense and luck, rather than persistent skill. Thus, pitchers with abnormally high or low BABIPs are good bets to see their performances regress to the mean. A typical BABIP is about .290.

EqA - Equivalent Average. A measure of total offensive value per out, with corrections for league offensive level, home park, and team pitching. EQA considers batting as well as baserunning, but not the value of a position player's defense. The EqA adjusted for all-time also has a correction for league difficulty. The scale is deliberately set to approximate that of batting average. League average EqA is always equal to .260. EqA is derived from Raw EqA, which is (H + TB + 1.5*(BB + HBP + SB) + SH + SF) divided by (AB + BB + HBP + SH + SF + CS + SB). REqA is then normalized to account for league difficulty and scale to create EqA.

OBP - On-base percentage. (H + BB + HBP) divided by (AB + BB + HBP + SF). For pitchers, OBP is on base percentage allowed.

SLG% - Slugging percentage (hitters) or slugging percentage allowed (pitchers). Total bases divided by at-bats.

OPS - On Base Percentage + Slugging Percentage

VORP - Value Over Replacement Player. The number of runs contributed beyond what a replacement-level player at the same position would contribute if given the same percentage of team plate appearances. VORP scores do not consider the quality of a player's defense.

BB/9 - Walks allowed per every 9 innings.

K/9 - Strikeouts per every 9 innings.

K/BB - Strikeout to Walk ratio

WHIP - Walks plus hits allowed per inning pitched.

wOBA - The statistic wOBA (weight on base average) is now available in the player pages, leaderboards, team pages, my team pages, and the projections. wOBA, created by Tom Tango, is a version of linear weights that has been weighted to fit an OBP scale. The weights have been properly adjusted by season and for the minor leagues by season and by league.

Linear Weights - This is kind of long winded, but go here for an explanation.

There's many more, we'll add as they come up.

[Seamhead]

http://www.fangraphs.com/blogs/index.php/glossary/

[Jilly Bohnson]

Courtesy of the links above:

BABIP - Batting Average on balls put into play. A pitcher's average on batted balls ending a plate appearance, excluding home runs. Based on the research of Voros McCracken and others, BABIP is mostly a function of a pitcher's defense and luck, rather than persistent skill. Thus, pitchers with abnormally high or low BABIPs are good bets to see their performances regress to the mean. A typical BABIP is about .290.

EqA - Equivalent Average. A measure of total offensive value per out, with corrections for league offensive level, home park, and team pitching. EQA considers batting as well as baserunning, but not the value of a position player's defense. The EqA adjusted for all-time also has a correction for league difficulty. The scale is deliberately set to approximate that of batting average. League average EqA is always equal to .260. EqA is derived from Raw EqA, which is (H + TB + 1.5*(BB + HBP + SB) + SH + SF) divided by (AB + BB + HBP + SH + SF + CS + SB). REqA is then normalized to account for league difficulty and scale to create EqA.

OBP - On-base percentage. (H + BB + HBP) divided by (AB + BB + HBP + SF). For pitchers, OBP is on base percentage allowed.

SLG% - Slugging percentage (hitters) or slugging percentage allowed (pitchers). Total bases divided by at-bats.

OPS - On Base Percentage + Slugging Percentage

VORP - Value Over Replacement Player. The number of runs contributed beyond what a replacement-level player at the same position would contribute if given the same percentage of team plate appearances. VORP scores do not consider the quality of a player's defense.

BB/9 - Walks allowed per every 9 innings.

K/9 - Strikeouts per every 9 innings.

K/BB - Strikeout to Walk ratio

WHIP - Walks plus hits allowed per inning pitched.

wOBA - The statistic wOBA (weight on base average) is now available in the player pages, leaderboards, team pages, my team pages, and the projections. wOBA, created by Tom Tango, is a version of linear weights that has been weighted to fit an OBP scale. The weights have been properly adjusted by season and for the minor leagues by season and by league.

Linear Weights - This is kind of long winded, but go here for an explanation.

There's many more, we'll add as they come up.

[Driven]

Yeah, I like this idea. Maybe edit all of the terms into the first post just for reference.

[Gigantes4Life]

http://statcorner.com/glossary.html

[ReyBrutal]

Do you guys put any stock into ERA+ and OPS+?

How about UZR and UZR/150 and +/-?

[C1Bman88]

Do you guys put any stock into ERA+ and OPS+?

How about UZR and UZR/150 and +/-?

ERA+, no. Calculation of it could be improved on and there's no real need to pay attention to ERA, at least on a single-season basis. Over the course of a pitcher's career, sure. OPS+ is (and I'm sure I might get some flack for this) basically useless. You can't add OBP and SLG together because they're not on the same scale. It undervalues OBP by quite a bit.

Plus/Minus is pretty good. UZR is better, but neither should be taken seriously on a single-season basis (too much noise in the data). UZR/150 is being cited a lot but I don't really see why. There's really no point in prorating defensive numbers in my opinion.

[ReyBrutal]

ERA+, no. Calculation of it could be improved on and there's no real need to pay attention to ERA, at least on a single-season basis. Over the course of a pitcher's career, sure. OPS+ is (and I'm sure I might get some flack for this) basically useless. You can't add OBP and SLG together because they're not on the same scale. It undervalues OBP by quite a bit.

Plus/Minus is pretty good. UZR is better, but neither should be taken seriously on a single-season basis (too much noise in the data). UZR/150 is being cited a lot but I don't really see why. There's really no point in prorating defensive numbers in my opinion.

I disagree with that first part, I'm a firm believer that a pitchers first job is to not allow any runs to score, regardless of how it's done. I know that the "+" stats need a 3 year basis of a stadium so YS and Citi Field are still working out little kinks... still I think that it is a fair measure since it adjusts to league averages.

I'll have to look up +/- again but there was a reason why I saw it as a better measure. I do see reason to measure defense numerically but I think it will be done better in the coming years. Did you hear about those cameras they installed in the top of every stadium which tracks like everyone on the defender, not sure if they went up yet but I read about it and it sounded interesting.

[C1Bman88]

I disagree with that first part, I'm a firm believer that a pitchers first job is to not allow any runs to score, regardless of how it's done. I know that the "+" stats need a 3 year basis of a stadium so YS and Citi Field are still working out little kinks... still I think that it is a fair measure since it adjusts to league averages.

I'll have to look up +/- again but there was a reason why I saw it as a better measure. I do see reason to measure defense numerically but I think it will be done better in the coming years. Did you hear about those cameras they installed in the top of every stadium which tracks like everyone on the defender, not sure if they went up yet but I read about it and it sounded interesting.

Well, there are certain things a pitcher has no control over, and I don't think they should be held responsible for good or bad defense behind them. There's too much fluctuation year to year when it comes to defensive support, so I don't trust ERA on a single-season basis. ERA+ is pretty good for multiyear sampling though. OPS+ is just plain misleading. As much as I love B-Ref, I wish Sean would fix a few things.

And yes, I've heard of this new system- it'll fix a lot of the issues with Plus/Minus and UZR. I actually posted a thread on it a few months ago.

[magichatnumber9]

I detest saber metrics. This is still a game right.

[C1Bman88]

I detest saber metrics. This is still a game right.

I detest trolls. This is a forum for fans of sabermetrics, right?

[OneTuzSea]

If anyone wants anymore glossaryness, MLB Network actually has a pretty decent one now: http://mlb.mlb.com/network/promotion...e_glossary.jsp. Gives a lot of lot of explanation in plain language too, which is nice.