xBA / xBA

Batter

Expected batting average: Savant's per-batted-ball estimate divided by at-bats, excluding at-bats whose batted ball carries no estimate. See runbook section 22.

Agreement with Savant

Checked nightly. Agreement tolerance: ±0.

Pitcher

Expected batting average against: Savant's per-batted-ball estimate divided by at-bats against, excluding at-bats whose batted ball carries no estimate. See runbook section 22.

Agreement with Savant

Checked nightly. Agreement tolerance: ±0.

Shown for: batter and pitcher.

Formula

COALESCE(sum(xba_num), 0) / NULLIF(sum(ab) - sum((ab = 1 AND bip = 1 AND xba_num IS NULL)::int), 0) — Savant's per-batted-ball estimate averaged over at-bats, excluding at-bats whose batted ball carries no estimate.

Inputs

pitches.estimated_ba_using_speedangle
plate_appearances.xba_num
plate_appearances.ab
plate_appearances.bip

Era caveats

Untracked contact leaves the denominator

Savant excludes batted balls it could not track rather than imputing them, and matching that is what closed the residual. The exclusion reaches the three expected stats by two different routes: xBA and xSLG subtract at aggregation time — at-bats minus at-bats whose batted ball carries no estimate — while xwOBA never counts them at all, because a plate appearance with no estimate never enters xwoba_den when its fact row is built. (runbook §10)

Three tracking systems across the seasons shown

Rows carry a tracking_era of trackman, hawkeye or hawkeye_bat (migration 001). The systems differ in what they measure and how precisely, so long spans cross a measurement boundary as well as a rule one.

Version history

2026-08-14 — Added with the expected-stats slice: estimated_ba_using_speedangle, typed out of the extras JSONB catch-all by migration 010 rather than refetched from Savant, since the bytes were already stored. (runbook §22)