The Best Box Score

Methodology

Every metric on The Best Box Score is computed from raw play-by-play and pitch-level data. Here's how the key features work.

Win Probability

Our win probability model uses pre-computed lookup tables based on historical MLB game states — inning, score differential, outs, base runners, and home/away. The WPA (Win Probability Added) for each play is the change in win expectancy from one state to the next.

The interactive chart on each game page shows the full arc of the game, highlighting the plays that swung the outcome the most.

Umpire Scorecard

We analyze every called pitch using Statcast tracking data and the MLB rulebook strike zone (17 inches wide, top and bottom defined per batter). A pitch is flagged as a missed call when it falls clearly inside or outside the zone but was called the opposite way, with a 0.5-inch margin of error for borderline pitches.

Each missed call is assigned a WPA impact value, and the total favor is expressed from the home team's perspective. Leverage labels (HIGH, VERY HIGH) indicate how much the game's outcome was at stake when the call was made.

Statcast Integration

Pitch-level data (velocity, spin rate, movement, location) comes from Baseball Savant CSV exports. This data is available for all MLB and most AAA games. Availability decreases at lower minor league levels.

Data Sources & Limitations

  • MLB Stats API — schedules, live feed, boxscores, play-by-play, player info
  • Baseball Savant — Statcast pitch-tracking data (CSV format)
  • Data is fetched live with a 30-second cache. Occasional gaps or delays may occur during active games.