Baseball intelligence
Baseball metric definitions
Definitions, formulas, interpretation and limitations of published baseball metrics.
Understand the measures
- pWAR — Value accumulates with playing time. Batting and pitching contributions are combined once for two-way players; do not add their displayed role totals together.
- pWAR+ — Batting uses primary season position; pitching uses exact starting and relief appearances. Role index contributions add once, retaining playing time, so multi-role totals do not share the single-role 100 and 0 anchors. Reference floors are 3.1 PA, 1 starting IP or 0.4 relief IP per average team game. Current-season and sparse references are provisional. Missing role evidence leaves the index unavailable. Not a percentile, talent rate or full-season projection.
- Tunneling — Lower inches mean the average fitted paths stayed closer during the measured window. A pitch type is compared with every other competitive type with fitted pitches, not only its nearest partner. With exactly two competitive types with fitted pitches, their type scores are equal by definition.
- Tunneling+ — 100 is the eligible cohort mean; higher means closer average paths. It is a rank index, not a percentage improvement, a measure of pitch effectiveness or a validated skill.
- OAA per 1,000 innings — Positive values mean more outs above average per 1,000 innings at the listed measured positions. It is an opportunity-scaled descriptive result, not a forecast or position-independent skill estimate.
- Pitcher rate indexes — 100 is the pooled retained reference for the same season, phase and batting side; higher is better. Reference rates use summed counts divided by summed outs, including zero-out appearances.
- Accumulated WPA — +1.00 is one accumulated win-probability unit. Pitcher credit has the opposite sign to batting-team credit. This is the accumulated sum, without leverage division or regression.
- Fielding Run Value (FRV) — Positive values represent defensive runs above average. Source season totals are separate from exact-position FRV rates and from OAA-derived range runs.