About

This website is your home for everything modern, public MLB analytics have to offer.

Glossary of Terms

On-Base Percentage (OBP): Measures how frequently a batter reaches base per plate appearance. Times on base include hits, walks and hit-by-pitches, but do not include errors, times reached on a fielder’s choice or a dropped third strike. Sacrifice bunts are removed from the equation.
On-base plus slugging (OPS): On-base percentage plus slugging percentage. OPS adds on-base percentage and slugging percentage to get one number that unites the two. Slugging percentage (SLG) represents the total number of bases a player records per at-bat. The formula for slugging percentage is: (1B + 2Bx2 + 3Bx3 + HRx4)/AB). OPS is meant to combine how well a hitter can reach base, with how well he can hit for average and for power.
Weighted on-base Average (wOBA): a version of on-base percentage that accounts for how a player reached base – instead of simply considering whether a player reached base.
Wins Above Replacement (WAR): measures a player’s value in all facets of the game by deciphering how many more wins he’s worth than a replacement-level player at his same position. It answers the question: How valuable is a player in comparison to replacement level?
Weighted runs created (wRC): estimates a player’s offensive value in terms of total runs. It combines a player’s ability to get on base with his ability to hit for extra bases, and divides those two by the player’s total opportunities.
Statcast baserunning above average (XBR): a Statcast metric designed to use data to evaluate the performance of baserunners and outfielders in taking or preventing extra bases.
Fielding Percentage (FP): total number of putouts and assists by a defender, divided by the total number of chances (putouts, assists and errors).
Defensive Runs Saved (DRS): quantifies a player’s entire defensive performance by attempting to measure how many runs a defender saved. It takes into account errors, range, outfield arm and double-play ability.
Fielding Independent Pitching (FIP): similar to ERA, but it focuses solely on the events a pitcher has the most control over – strikeouts, walks, hit-by-pitches and home runs. It entirely removes results on balls hit into the field of play.

Run Expectancy Charts

Resources and Inspiration

The below resources were used to create the above plots within this document. Many thanks to all the authors of these fantastic resources:

Title/Link	Author	Description
Tango Tiger blog	Tom Tango	One of the Godfathers of sabermetrics/baseball analytics
Fangraphs	Fangraphs	Top tier advanced stats and analysis.
Baseball Savant	MLB	The official home of MLB’s advanced stats and analysis including Statcast data.
nflfastR Graphics Cookbook	Thomas Mock	As step-by-step guide on how to improve your nflfastR graphics.