MLB's advanced stats broken down into layman's terms

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 waiting in the wings? And how many wins did he add to his team's total that season compared to if he wasn't in the lineup? It takes into account a player's offense, defense and baserunning. Pitchers' WAR has its own metrics. Three websites — FanGraphs, Baseball Reference and Baseball Prospectus — have different variations of this statistic. They differ the greatest in what metrics they use to calculate a player's defense and how they evaluate pitchers. So a player's WAR on one website can be different from the others.

Good, bad and average: These are the general ranges across each version of WAR — below zero is replacement level; 0.0-2.0 is a bench player; 2.0-5.0 is a starter; 5.0-8.0 is an All-Star; and above 8.0 is MVP-worthy.

OPS (on-base percentage plus slugging percentage) and OPS+ (OPS plus)

OPS is a statistic that can sound more complicated than it is — it adds a player's 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. Boston's Mookie Betts leads the majors with a 1.101 OPS.

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; .311 to .320 below average; .321 to .340 average; .341 to .370 above average; .371 to .400 very good; .401 and up is excellent.

wRC (weighted runs created) and wRC+ (weighted runs created plus)

Updates a statistic Bill James devised called runs created. It uses a player's weighted on-base average to determine a player's 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.

Good, bad and average: For wRC+, 60 is awful; 75 is poor, 80 is below average, 100 is average, 115 above average, 140 great, 160 is excellent. While Trout leads the majors (196), Eddie Rosario leads all Twins players with a 146 wRC+.

How hard the ball is hit off the bat, in miles per hour. This was introduced in 2015 with the launch of MLB's Statcast, the technology that provides a lot of advanced data.

Good, bad and average: Anything 95 mph and above is hard hit. Most home runs are around the 100 miles per hour mark or greater. The hardest hit ball this season was 121.1 mph by the Yankees' Gary Sanchez. Anything from the mid 80s to 90 is moderately hit and the low 80s and below is not that hard and unlikely to result in a hit.

Launch angle

The angle at which the ball comes off the hitter's bat, with the point of contact serving as the vertex of the angle. Players in recent seasons have tried to raise their average launch angle in an attempt to hit more home runs.

Good, bad and average: MLB.com says 10 degrees or less is a ground ball; 11-25 degrees is a line drive; 26-50 degrees is a fly ball; 51 degrees and up is a pop-up. Most homers occur just above the 25 degree line. Anything in that area, provided it has a hard-hit exit velocity, is likely to result in an extra-base hit or a home run.

This statistic only focuses on balls a batter puts in play. It does not take into account home runs. It shows how often a batter gets a hit when he puts the ball in the field of play. It can also be used to evaluate pitchers to see what their batting average of balls in play is against them. You can use BABIP to determine how lucky or unlucky a hitter is. If a hitter has a high BABIP, it usually means he's getting lucky. If it's low, he might be unlucky. This works in reverse for pitchers.

Good, bad and average: The average tends to be around .300, but you have to take into account each individual when using BABIP. For example, if a hitter has had a career .280 average BABIP but in a given season it's .330, that might mean he is a bit lucky. Or maybe he's hitting the ball harder. You can then use his average exit velocity to see if that's the case. For pitchers, a lower BABIP than their career averages might mean they are benefiting from luck, good defense or they're inducing softer contact.

Catch probability

According to MLB.com, it's the "likelihood that a batted ball to the outfield will be caught, based on four important pieces of information. 1. How far did the fielder have to go? 2. How much time did he have to get there. 3. What direction did he need to go in? 4. Was proximity to the wall a factor?"

Good, bad and average: Every fly ball gets assigned a catch probability percentage. MLB has a star-rating system for each catch. A catch with a 0-25 percent catch probability is a five-star play; 26 to 50 is four star; 51 to 75 percent is three star; 76 to 90 is two star; 91-95 percent one star.

This attempts to quantify how many runs a fielder saved because of his range, his arm strength (for outfielders) and double plays turned (for infielders). It attempts to quantify every batted ball event in terms of the amount of effort it would take an average fielder to make the play. Its calculations vary by position. Another related statistic is defensive runs saved (DRS).

Good, bad, average: Per FanGraphs, the scale for both UZR and DRS is: -15 awful; -10 poor; -5 below average; 0 average; +5 above average; +10 great; +15 Gold Glove caliber.

FIP (fielding independent pitching)

A metric similar to ERA, but FIP uses all the batted ball events within a pitcher's control (the amount of strikeouts, walks, hit by pitches and home runs allowed) and puts them into a complicated formula to show how a pitcher would perform regardless of the defense behind him.

Good, bad and average: The numbers compare to ERA. FIP can be helpful if there's a significant gap between a pitcher's ERA and his FIP. If his ERA is lower than his FIP, it could suggest he has been a bit lucky and had good defense behind him. If his FIP is lower than his ERA, he might be getting unlucky.

It adds together the walks and hits a pitcher allows to give you an indication of how often a pitcher allows baserunners in an inning. Whether it was a walk or a home run, each time a batter reaches base is treated the same.

Good, bad and average: WHIP varies by season, but according to FanGraphs a general guide is this: 1.6 awful; 1.5 poor; 1.4 below average; 1.3 average; 1.2 above average; 1.1 great; 1.0 excellent.

Spin rate

How much a ball spins out of the pitcher's hand to home plate. It is measured in revolutions per minute. Data have suggested that fastballs and breaking balls are harder to hit when they have a high spin rate, which can create more movement on the pitch.

Good, bad, average: It varies by pitch. For a four-seamer, the average in 2016 was around 2,226 rpm; two-seamer was 2,123; splitter 1,524; changeup 1,746; slider 2,090; curveball 2,308.