The recordWritten before first pitch.
Written before first pitch.
Never edited after.
Since Sep 17, 2026, every prediction is frozen at first pitch. Later builds may add the result and the closing price; none may change the prediction. What follows is graded from those frozen rows, including where the book is still ahead of us.
Every market
Model cards →| Market | Backtest skill | Live test | Vs closing price |
|---|---|---|---|
| Pitcher strikeouts | 25.8% 22.6% to 28.8% | 164 over 26 dates needs 200 over 7 | Book more accurate +0.087 (+0.056 to +0.122) across dates +0.053 to +0.135 275 predictions over 12 dates · engines v10–v14 |
| 1+ hit | 1.4% 1.0% to 1.8% | 1,473 over 26 dates past the minimum · re-grade pending | No clear difference +0.013 (+0.001 to +0.025) across dates -0.005 to +0.032 1,053 predictions over 5 dates · engine v8 |
| 2+ total bases | 1.2% 0.9% to 1.6% | 1,473 over 26 dates past the minimum · re-grade pending | No clear difference +0.010 (+0.003 to +0.020) across dates -0.001 to +0.024 712 predictions over 5 dates · engine v8 |
| 1+ home run | 1.5% 1.0% to 1.9% | 1,473 over 26 dates research only | No clear difference +0.007 (+0.001 to +0.016) across dates -0.004 to +0.020 867 predictions over 5 dates · engine v8 |
| Game total | -0.7% -3.1% to 1.8% | 53 over 24 dates research only | not measured |
| Moneyline | 1.3% -0.2% to 2.9% | 81 over 26 dates research only | Too few to read +0.023 (+0.003 to +0.043) across dates -0.002 to +0.058 81 predictions over 9 dates · engine v8 |
| First inning (NRFI/YRFI) | – | 81 over 26 dates research only | not measured |
Did the numbers mean what they said?
4 calibration charts · 2,944 settled hitter games and 328 starts, frozen before first pitch · Sep 17, 2026 to Oct 28, 2026
Brier 0.2395 vs 0.2417 for always saying the average (better). Said 57.9% on average; happened 59.1%.
Brier 0.2213 vs 0.2224 for always saying the average (better). Said 33.5% on average; happened 33.4%.
Brier 0.0919 vs 0.0934 for always saying the average (better). Said 10.8% on average; happened 10.4%.
Correlation 0.50, RMSE 2.34 strikeouts. Projected 4.73 a start on average; he got 4.41.
Each dot is an equal-sized group of games, placed at what we said against what happened, with its 95% interval. On the dashed line is honest; dots spread along it is skill. Pooled across every engine that served these games (engine v11, engine v12, engine v13, engine v14), because that is what readers saw. The samples are small: read the intervals before the dots.
Strikeouts at the line, start by start
Latest 40 of 292 graded pre-game starts over 34 dates, every engine, updated with every buildBTB's side right156 of 29253.4%
Book's favorite right158 of 29254.1%
Overs137 of 29246.9%
Brier, all 292 graded starts.259book .244 · coin .250 · lower is better
| Date | Starter | Line | BTB over | Book over | Strikeouts | Result | BTB's side |
|---|---|---|---|---|---|---|---|
| Oct 28 | Drew Rasmussen TB vs MIL | 4.5 | 66.7% | 54.0% | 4 | Under | Over · wrong |
| Oct 28 | Jacob Misiorowski MIL vs TB | 5.5 | 53.2% | 55.8% | 2 | Under | Over · wrong |
| Oct 27 | Dustin May MIL vs TB | 2.5 | 57.1% | 42.2% | 3 | Over | Over · right |
| Oct 27 | Griffin Jax TB vs MIL | 3.5 | 65.9% | 50.0% | 6 | Over | Over · right |
| Oct 26 | Freddy Peralta TB vs MIL | 4.5 | 52.4% | 52.4% | 4 | Under | Over · wrong |
| Oct 26 | Robert Gasser MIL vs TB | 3.5 | 49.6% | 44.2% | 3 | Under | Under · right |
| Oct 24 | Drew Rasmussen TB vs MIL | 5.5 | 59.2% | 56.5% | 4 | Under | Over · wrong |
| Oct 24 | Logan Henderson MIL vs TB | 4.5 | 52.5% | 52.9% | 4 | Under | Over · wrong |
| Oct 23 | Jacob Misiorowski MIL vs TB | 6.5 | 35.9% | 54.4% | 3 | Under | Under · right |
| Oct 23 | Nick Martinez TB vs MIL | 3.5 | 49.5% | 38.9% | 5 | Over | Under · wrong |
The 30 starts before these
| Date | Starter | Line | BTB over | Book over | Strikeouts | Result | BTB's side |
|---|---|---|---|---|---|---|---|
| Oct 19 | Freddy Peralta TB vs CLE | 4.5 | 36.1% | 42.4% | 3 | Under | Under · right |
| Oct 18 | Drew Rasmussen TB vs CLE | 5.5 | 41.9% | 44.6% | 6 | Over | Under · wrong |
| Oct 18 | Parker Messick CLE vs TB | 4.5 | 55.9% | 53.3% | 3 | Under | Over · wrong |
| Oct 17 | Nick Martinez TB vs CLE | 2.5 | 54.9% | 39.9% | 3 | Over | Over · right |
| Oct 15 | Gavin Williams CLE vs TB | 6.5 | 48.0% | 47.0% | 9 | Over | Under · wrong |
| Oct 15 | Griffin Jax TB vs CLE | 3.5 | 64.3% | 54.7% | 2 | Under | Over · wrong |
| Oct 15 | Tyler Glasnow LAD vs MIL | 5.5 | 71.1% | 58.7% | 6 | Over | Over · right |
| Oct 14 | Blake Snell LAD vs MIL | 6.5 | 42.0% | 45.0% | 9 | Over | Under · wrong |
| Oct 14 | Robert Gasser MIL vs LAD | 3.5 | 51.6% | 45.6% | 3 | Under | Over · wrong |
| Oct 13 | Freddy Peralta TB vs CLE | 3.5 | 55.4% | 53.4% | 6 | Over | Over · right |
| Oct 13 | Parker Messick CLE vs TB | 4.5 | 52.5% | 48.4% | 3 | Under | Over · wrong |
| Oct 12 | Drew Rasmussen TB vs CLE | 5.5 | 40.3% | 50.0% | 7 | Over | Under · wrong |
| Oct 12 | Foster Griffin CLE vs TB | 3.5 | 59.2% | 50.0% | 3 | Under | Over · wrong |
| Oct 12 | Logan Henderson MIL vs LAD | 5.5 | 50.2% | 48.1% | 2 | Under | Over · wrong |
| Oct 12 | Yoshinobu Yamamoto LAD vs MIL | 6.5 | 55.4% | 52.4% | 1 | Under | Over · wrong |
| Oct 11 | Jacob Misiorowski MIL vs LAD | 7.5 | 32.4% | 45.9% | 5 | Under | Under · right |
| Oct 11 | Tarik Skubal LAD vs MIL | 7.5 | 40.8% | 43.3% | 7 | Under | Under · right |
| Oct 10 | Gavin Williams CLE vs CWS | 6.5 | 71.6% | 53.3% | 12 | Over | Over · right |
| Oct 10 | Sean Burke CWS vs CLE | 3.5 | 69.1% | 55.8% | 4 | Over | Over · right |
| Oct 8 | Hagen Smith CWS vs CLE | 1.5 | 71.2% | 59.4% | 0 | Under | Over · wrong |
| Oct 8 | Parker Messick CLE vs CWS | 5.5 | 60.8% | 54.8% | 5 | Under | Over · wrong |
| Oct 7 | Max Fried NYY vs TB | 4.5 | 40.0% | 47.6% | 7 | Over | Under · wrong |
| Oct 7 | Nick Martinez TB vs NYY | 2.5 | 70.6% | 59.7% | 3 | Over | Over · right |
| Oct 7 | Robert Gasser MIL vs SD | 2.5 | 78.0% | 48.3% | 3 | Over | Over · right |
| Oct 7 | Tyler Glasnow LAD vs ATL | 6.5 | 58.1% | 46.0% | 5 | Under | Over · wrong |
| Oct 7 | Tyler Mahle ATL vs LAD | 3.5 | 72.0% | 58.4% | 4 | Over | Over · right |
| Oct 7 | Walker Buehler SD vs MIL | 2.5 | 70.6% | 56.7% | 0 | Under | Over · wrong |
| Oct 6 | Chris Sale ATL vs LAD | 7.5 | 35.0% | 43.3% | 7 | Under | Under · right |
| Oct 6 | Dustin May MIL vs SD | 2.5 | 75.3% | 57.3% | 3 | Over | Over · right |
| Oct 6 | Nick Pivetta SD vs MIL | 3.5 | 62.8% | 58.4% | 4 | Over | Over · right |