Advanced baseball statistics can be hard to understand and often contain more acronyms than the New Deal. Here is a list of 12 terms that are widely used with an explanation of what they measure.
WAR (or WARP, wins above replacement player)
WAR attempts to encapsulate the value of all players across all positions for a season: How much better or worse is a player than a theoretical call-up a team has waiting in the wings? And how many wins did he add to his teams total that season compared to if he wasnt in the lineup? It takes into account a players offense, defense and base running. Pitchers WARs have their own metrics. Three websites, Fangraphs, Baseball Reference and Baseball Prospectus, have different variations of this statistic. They differ the greatest in what metrics (some of which are on this list) they use to calculate a players defense and how they evaluate pitchers. So a players WAR on one website can be different than the others.
Good, bad and average: These are the general ranges across each version of WAR _ below 0 is replacement level; 0-2 is a bench player; 2-5 is a starter; 5-8 is an All-Star and above 8 is MVP-worthy.
Examples: Mike Trout of the Angels leads the majors with a 6.3 WAR (all stats through Wednesday), according to Fangraphs, and Eddie Rosario leads the Twins with a 3.6 WAR (13th in MLB). Joe Mauers WAR this season is .5; during his 2009 MVP season it was 7.6.
OPS (on-base percentage plus slugging percentage) and OPS+ (OPS plus)
OPS is a statistic that can sound more complicated than it is it simply adds a players on-base and slugging percentages together to show how often he reaches base and hits for power. OPS+ makes small adjustments to OPS and scales it to a more easily digestible number with 100 being the league average and each point up or down being 1 percent better or worse than league average.
Good, bad and average: That changes by year, but according to Fangraphs, an OPS of .570 and below is awful, .600 is poor, .670 is below average, .710 is average, .800 is above average, .900 is great, 1.000 excellent. For OPS+, 150 and up is excellent. 125-150 is very good. Below 75 is poor.
Examples: Bostons Mookie Betts is edging out Trout in OPS so far this season: 1.103 to 1.089.
wOBA (weighted on-base average)
This is a more refined statistic that attempts to improve on OPS. Instead of counting the value of a double as twice that of a single (as slugging percentage does), wOBA attempts to use that actual mathematical value of each outcome at the plate (walks and hit batters included) in how it usually contributes to scoring a run.
Good, bad and average: The average changes by season, but these are generally the accepted ranges, according to Fangraphs: below .300 awful; .300 to .310 poor; .310 to .320 below average; .320 to .340 average; .340 to .370 above average; .370 to .400 very good; .400 and up is excellent.
Example: Betts leads MLB at .458 with Trout at .450. Bostons JD Martinez is third at .428, giving the Red Sox two of the top three players in that statistic.
wRC (weighted runs created) and wRC+ (weighted runs created plus)
Updates a statistic Bill James devised called runs created. It uses a players weighted on-base average to determine a players offensive value and measure it in runs. wRC+ takes every outcome a hitter had and adjusts for the park he was playing in and how the rest of the league was scoring that season. Similar to OPS+, wRC+ uses a scale with 100 as the league average.
