Advanced Baseball Stats Glossary

WAR – Wins Above Replacement

WAR estimates how many more wins a player is worth compared to a replacement-level player at the same position. It combines offensive, defensive, and baserunning contributions. A WAR of 8+ is MVP caliber.

wRC+ – Weighted Runs Created Plus

wRC+ measures a player’s total offensive value, adjusted for park and league factors. 100 is league average. A 150 wRC+ means a player creates 50% more runs than league average.

xwOBA – Expected Weighted On-Base Average

xwOBA uses exit velocity and launch angle to estimate what a player’s performance should be based on quality of contact, walks, and strikeouts. It helps remove luck from actual outcomes.

FIP – Fielding Independent Pitching

FIP evaluates a pitcher’s effectiveness at limiting HRs, walks, and strikeouts, ignoring defense. It gives a clearer sense of a pitcher’s true talent than ERA.

BABIP – Batting Average on Balls In Play

BABIP shows how often batted balls fall for hits, excluding HRs and strikeouts. League average is around .300. A high or low BABIP can signal luck or poor contact quality.

ISO – Isolated Power

ISO is slugging percentage minus batting average. It tells you how often a player hits for extra bases. .250+ is elite power.

OPS+ – On-Base Plus Slugging (Adjusted)

OPS+ adjusts a player’s OPS for league and park factors. 100 is league average. A 130 OPS+ means the player is 30% better than average offensively.

Barrel % – Barrel Rate

Barrel % shows how often a hitter makes ideal contact (high exit velocity + launch angle). It’s highly predictive of extra-base hit power.

CSW% – Called Strikes + Whiffs

Used for pitchers, CSW% combines called strikes and swinging strikes to show how often a pitcher dominates at the plate. A CSW% above 30 is excellent.

Hard Hit % – Hard Contact Rate

The percentage of batted balls hit 95+ mph. A good proxy for power and quality contact. League average is around 38%.