I have compiled a list of many of the stats that will appear in my posts with a brief summary…Use control-F to search for certain stats!
On-base Percentage (OBP) : A measure of how often a player reaches base safely. Billy Beane‘s bread and butter.
= (H + BB + HBP) / (AB + BB + HBP + Sac Flies)
Slugging Percentage (Slugging): A measure of the average number of bases per at bat.
= (Singles + 2*Doubles + 3*Triples + 4*Homeruns) / At bats
Weighted on-base Average (wOBA): A statistic from Fangraphs that is scaled to match OBP, but includes stats like reaching on errors, while separating out values for singles, doubles, triples and home runs. When analyzing a player’s wOBA, this year .310-.320 would be considered average.
wRC+: Basically a player’s wOBA adjusted for ballpark effects, and then compared to league average. 100 is considered league average, and 107 would indicate that a player is 7% better than league average. Great for comparing Rockies to Padres.
On-base plus Slugging (OPS): The sum of OBP and Slugging (or weighted slugging). Though it has little intuitive meaning, it is a very good indicator of run scoring.
=OBP + Slugging
Batting Average on Balls In Play (BABIP): A measure of how often a ball hit into the field of play becomes a hit. Used often to determine how much luck is playing a role in a given player’s performance over the short term. Can also be used for pitcher analysis.
= (H – HR) / (AB – SO – HR + SF)
A more complete explanation of BABIP can be found here.
Wins Above Replacement (WAR): Fangraphs version. A single number that attempts to completely value a player. Measured in wins, WAR basically says, “take your AAA-replacement player at third and stick Adrian Beltre there instead. Beltre’s WAR was about 5 in 2011, so your team should win about 5 additional games.” War can be calculated for both hitters and pitchers. For hitters it is based on wOBA and UZR, for pitchers it is based on FIP.
xFIP and FIP (Fielding-independent Pitching): Fangraphs’ ERA equivalents, adjusted for good and bad “luck.” These statistics tend to be good predictors in the short term of a pitcher’s true ability.
Strand Rate (LOB%): A pitcher’s measure of the percentage of opposing hitters that reach base yet never score. Also used to measure “luck” in pitcher’s performance. I put “luck” in quotes because in some cases, pitchers simply get unlucky, and in others, they suck with runners on base.
= (H + BB + HBP – R) / (H + BB + HBP – 1.4*HR)
A more complete explanation of LOB% can be found here.
Double Play Percentage: The rate at which a team or player hits into double plays.
= (Double plays*) / (Instances in which a runner was on first with less than 2 outs)
*Often times just ground out double plays are used.
Team Defensive Efficiency: A measure of how often a defense takes a ball in play and turns it into an out. Similar to the BABIP statistic in theory, except adjusted for defenses. Note: ROE is runners that Reached On an Error.
=1 – ((H + ROE – HR) / (PA – BB – SO – HBP – HR))
Ultimate Zone Rating (UZR): Fangraphs’ defensive rating given to a player (or team of players) that measures the quality of his defense in terms of how many runs he (or they) is estimated to have saved his team over an average player. It is calculated based on four factors: throwing arm, range, error reduction and double plays efficiency. A positive number reflects an above-average player.