Analytics Glossary

The mean speed at which a batter hits the ball as measured by Statcast, excluding topped or weakly hit balls, typically above 60 mph.

Mean vertical angle of all batted balls for a hitter, indicating approach (fly ball vs ground ball tendency).

The difference between actual batting average and expected batting average.

The batting average on balls put into play, calculated as (H - HR) / (AB - K - HR + SF). League average is typically around .300.

A Statcast classification for batted balls with the ideal combination of exit velocity and launch angle, generally 98+ mph exit velocity with launch angles between 26-30 degrees, with the range expanding as exit velocity increases.

Percentage of batted ball events classified as barrels, representing the best possible contact outcomes.

Component of WAR measuring runs created or lost from hitting, relative to average.

Batted balls with both high exit velocity (95+ mph) and optimal launch angle (10-30 degrees), indicating well-struck line drives.

The speed at which the ball leaves the bat after contact, measured in miles per hour by Statcast. League average is approximately 88-89 mph.

Statcast metric estimating batting average based on exit velocity and launch angle of batted balls, removing the influence of luck and defense.

Statcast metric estimating wOBA based on quality of contact (exit velocity and launch angle) rather than actual outcomes.

Percentage of batted balls classified as hard contact based on exit velocity, typically 95+ mph. League average is approximately 35-40%.

A measure of raw power calculated as SLG - AVG, or (2B + 2×3B + 3×HR) / AB. League average is approximately .145.

The vertical angle at which the ball leaves the bat, measured in degrees. Optimal angles for home runs are typically 25-35 degrees.

See Exit Velocity.

Frequency with which a batter reaches base, calculated as (H + BB + HBP) / (AB + BB + HBP + SF). League average is approximately .320.

Total offensive value combining batting runs and baserunning runs in WAR calculations.

OPS scaled and adjusted for park factors so that 100 is league average, with higher being better.

Arrangement of batting order to maximize expected runs, often placing highest OBP at top.

Baseball Prospectus's Player Empirical Comparison and Optimization Test Algorithm, a projection system.

Total number of completed batting appearances, calculated as AB + BB + HBP + SF + SH.

Total bases per at-bat, calculated as (1B + 2×2B + 3×3B + 4×HR) / AB or TB / AB. League average is approximately .400.

Percentage of batted balls with launch angles between 8-32 degrees, optimal for base hits.

The degradation in pitcher performance each time through the batting order, typically 0.3-0.4 runs per time through.

A comprehensive metric estimating the total number of wins a player contributes above a replacement-level player, combining batting, baserunning, fielding, and positional value.

An advanced batting metric that weights different offensive events (singles, walks, home runs, etc.) by their actual run value, scaled to OBP. League average is approximately .320.

The constant used to convert wOBA to runs, typically between 1.15-1.25, varying by season based on run environment.

The difference between actual wOBA and expected wOBA, indicating luck or over/underperformance.

Runs created above average based on wOBA, calculated as ((wOBA - lgwOBA) / wOBA_scale) × PA.

wRC scaled so that 100 is league average and adjusted for park factors, with higher being better. Accounts for both league and park context.

Statcast metric estimating what a player's batting average should be based on exit velocity and launch angle, removing luck and defense.

ERA estimator based on expected outcomes from quality of contact metrics like xwOBA, xBA, and barrel rate.

Expected ISO based on batted ball quality, excluding luck and defense.

Statcast metric estimating slugging percentage based on batted ball quality (exit velocity and launch angle).

Statcast metric estimating wOBA based on exit velocity and launch angle rather than actual outcomes, designed to measure quality of contact independent of luck.

xwOBA calculated only on contacted balls, excluding strikeouts and walks, isolating pure batted ball quality.

Dan Szymborski's projection system using player comparisons and aging curves.