Here at Behind the Plate, particular statistics or phrases obscure and unknown to some, will be used to support a particular stance by the author. Some of the more frequently used statistics and their meaning are as followed.
BABIP: Batting Average on Balls in Play measures the amount of balls put in play that go for hits. League average BABIP is around 30%, or .300. There are three different variables that can affect the BABIP for an individual player. One is luck, such as a bloop over the shortstop, or a swinging bunt down the line. Sometimes hits just fall in regardless of who is pitching or what kind of defense is on the field. Another is defense. Players have no control on the defense against them and even a hard hit ball can go for an out. Lastly, as players adjust throughout a season, so to will be there ability to make solid contact. If a player is in a slump, he will have a lower BABIP while a player on fire will have a higher one. Often, if a player deviates from the .300 mark, he is usually a recipient of good or bad luck. Often, if this occurs players will eventually "regress to the mean" or return to average. That's why players cannot sustain .400 batting averages for an entire season. There are exceptions such as pitchers who continually limit hard contact will continually post low BABIPs while faster, speedier hitters will tend to have higher BABIPs due to their ability to outrun many close plays. Also, players who hit a large amount of line drives will also post higher BABIP rates due to his propensity for hard contact. BABIP rates will fluctuate from year to year and should be taken with a grain of salt for particularly extreme rates. ERA +: Earned Run Average Plus is a measure of a league-adjusted, ballpark-adjusted, rate of one's ERA. An 100 ERA+ is league average and is able to compare pitcher's across leagues, different parks, and generations, since park effects and other variables are neutralized. FIP: Fielding Independent Pitching measures what a pitcher's ERA should look like over a given period of time. Since pitchers have little control over balls in play and the defense behind him, FIP assesses only what pitchers can control: strikeouts, walks, hit by pitches, and home runs. By only evaluating what the pitcher can control, FIP offers insight to how a particular pitcher may perform in the future, which is closer to his true talent level. FIP is on the same scale as ERA and thus a sub-3.00 FIP remains an excellent rating for a pitcher just as a sub-3.00 ERA is. FIP is more accurate and appropriate when assessing an entire season's worth of work compared to a small sample size. LI: Leverage Index is a statistic that indicates the possible changes of win expectancy during a given time. During a more tense situation, leverage index rates are higher due to the severity of the present situation. Obviously a one run lead with two runners on base has a much higher LI than a ten run blowout with no one on base. Average LI is 1.0, where "high leverage" situations have LI's greater than 1.5 and "low leverage" situations have LI's below 1.0. MD/SD: Meltdowns and Shutdowns are a pair of statistics that are used as a substitute to the complex and often ridiculous save statistic. Meltdowns and shutdowns simply ask the question: Did a pitcher help or hurt his team's chances of winning. If the pitcher did his job and improved his team's win probability, he gets a shutdown. If he hurts his team's chances of winning, he gets a meltdown. By using Win Probability Added, a player that improves his team's chances of winning by 6% (.06 WPA), he gets a shutdown. If he made his team 6% more likely to lose, he gets a meltdown. By stripping away the save statistic, equal weight is given towards middle relievers and often correlate quite well with saves and blown saves. Therefore, a pitcher that has 40 shutdowns remains an excellent reliever just as a 40 save reliever would be. RE: Run Expectancy is essentially the expectancy that a run will score given a particular situation. Any change from the run expectancy at the start of the play to the end of the play is credited to the batter and pitcher accordingly.RF: Range Factor is the number of successful plays made in the field of play. It is found by taking the number of putouts and assists divided by the amount of innings played times nine. OPS +: On-Base Plus Slugging Plus stabilizes a players OPS by leveling out park effects and other variables that may affect a batter's score. An 100 OPS+ is league average and anything above is deemed above average and vice versa for anything below. Since OPS+ adjusts for the league and parks, players across generations can be compared despite playing in completely different parks, leagues, and eras. OWn%: Offensive Winning Percentage indicates the percentage of games that would be won with nine of a particular player batting with assumed average fielding and pitching. Scouting Scale: The scouting scale is used by scouts when evaluating talent. The scouting scale is from 20-80 where 50 represents a major league average. 60 is considered "plus" and is all-star caliber, 70 is considered "plus-plus" and is elite, and 80 is among the best in the game. These numbers can be used when evaluating a specific skill, or "tool" or can evaluate a player himself. For example, Aroldis Chapman has an 80 fastball (one skill/tool), while Miguel Cabrera is 70 player (combination of skills). Triple Slash: A reference to a triple slash line is a player's batting average, on-base percentage, and slugging percentage. An example of a .300/.400/.500 triple slash refers to a player that has a .300 batting average, .400 on-base percentage, and a .500 slugging percentage. UBR: Ultimate Base Running is the way of determining how much value each individual base running event influences chances of scoring a run. Base running events such as going from first to third and tagging up are included in this measure. Often a good UBR is above 3-4 while 0 represents average. UZR: Ultimate Zone Rating attempts to quantify how many runs were saved (or inversely given up) through their arm, range, and errors committed. Average is 0 runs whereas gold glove caliber players will post UZRs of +10 runs saved. UZR is best when observing large sample sizes and are most accurate with 2-3 years of fielding data. Additionally, UZR is park-adjusted, compromising for the fact that different fielders have to play depending on each ballpark. WAR: Wins Above Replacement is an attempt to combine all of a player's contributions towards his team in one statistic. This statistic refers to how many extra wins a team would have if a particular player played instead of calling up a cheap, inexperienced minor leaguer that could be readily attained. WAR takes the additional value provided by that player through his offensive, defensive, and base running contributions. Pitchers WAR is calculated often by how many runs are allowed and how many innings he pitched. The rough number of wins added per player are as follows: a bench player will be between 0-2 WAR, the average everyday player's WAR will be 2+, a solid starter around 3-4 WAR, an all star would be 5+, and a MVP quality season around 7+ WAR. Sometimes, just oWAR or dWAR will be quoted to strictly examine a player's offensive or defensive wins above replacement. The WAR numbers quoted in various articles will use baseball-reference.com version. wOBA: Weighted On Base Average accounts for how a player got on base and weighs each aspect of hitting according to its run value. WPA: Win Probability Added captures the context of when a play occurs and magnifies its importance. For example a second inning home run is not as important as a home run to tie the game in the bottom of the ninth. WPA is measured by how a player affects his team of winning. For example, a home run that improves a team's chances of winning by 40% will credit the player who hit that home run with .40 WPA. WPA is a cumulative statistic with often the best players in the league posting 4.5+ WPAs with league average around 1 WPA. 1 WPA correlates to an 100% win expectancy or one win. Although, WPA is not a good predictive statistic, it shows how much of an impact a particular player had on his team that particular statistic. XBT%: Percentage of times a base runner advances more than a base on a single and more than two bases on a double when it is possible.