Expected Swing Value
For every pitch a batter faces, there is a correct decision: swing or take. We compute the Expected Swing Value (ESV), the difference in expected run value between swinging and taking, using the pitch type, location, velocity, count state, base-out situation, and the batter's own contact history against that pitch profile. Grade the actual decision against the higher-EV option and aggregate to a season leaderboard showing who is adding (or costing) their team runs through pitch-selection quality alone.
Key finding: 4.50 million pitch decisions graded across 2020–2026. Year-over-year stability rho +0.60 (hitters with 750+ pitches in both seasons, 2021–2026); swing/take decision quality is a repeatable batter skill. The league average correct decision rate is 68.1%. Among hitters with 750+ pitches, the best single seasons add roughly +5 to +6 runs per 100 pitches above the league mean; the worst cost roughly 4 to 5.
Pitch decisions graded
4.50M
Swings + takes, 2020–2026
League correct rate
68.1%
Decisions matching the higher-EV option
YoY stability (rho)
+0.60
RAA/100, hitters with 750+ pitches in both seasons, 2021–2026
Batter-seasons graded
3,618
Min 200 pitches seen per season
By batter-season
About these grades
Every pitch is binned by type, location zone, velocity tier, and pitcher handedness. For each bin, we compute E(swing), the expected run value of swinging, using the batter's empirical contact rate and average contact run-value delta against that pitch profile from earlier seasons only (minimum 50 prior pitches; otherwise the league average, which covers most pitches), and E(take), derived from umpire call-rate empirics by zone and pitcher hand, crossed with a count-state run-expectancy table. ESV = E(swing) − E(take). Each pitch is graded by whether the batter chose the higher-EV option. Run value is leverage-weighted by RE24 (base-out state) and expressed as runs above league average per 100 pitches. Entries marked Low have fewer than 500 pitches and carry higher uncertainty. 2020 entries are flagged 60g.
Full methodology · Does decision quality predict the future?