1+ home run

Research only by policy. It passes the backtest. The live forward test is still running: 0 of 200 settled results over 0 of 7 dates.

Research only: Tier 3 by policy. Published for context, never as a basis for a bet, until a deliberate product change promotes it. Tier 3: Research only until proven.

The backtest

engine v14 · starters only · walk-forward

Graded17,284over 72 dates

Skill vs league rate1.5%1.1% to 1.9% (95%)

Predicted, on average11.5%what happened: 11.6%

Calibration slope0.911.00 is ideal; 0.80–1.20 passes

Ranking (AUC).612.500 is a coin flip

Skill is how much lower the Brier score of the served number is than always guessing the league-wide rate known at the time. Every date is predicted using only earlier dates, with calibration curves refit each date the way the site serves them.

Against the player's own record

Model better

Compared with the hitter's own record, shrunk toward the league. Difference in log loss, model minus player: -0.0032 (95% interval -0.0047 to -0.0019). Negative means the model is more accurate.

The live test · engine v14

0 of 200 settled results · 0 of 7 dates

Only predictions frozen before first pitch, under the engine now serving, count. The count restarts with every engine version, which is why nothing is Validated yet.

The last engine with a finished live sample (engine v8, 2,808 results over 12 dates) showed skill of 2.4% (1.3% to 3.5%).

Against the book's closing price

Book more accurate

Log loss, model minus the no-vig closing price: +0.007 (95% interval +0.001 to +0.016) on 867 predictions over 5 dates, engine v8. Positive means the book was more accurate. This comparison changes no status; it answers whether the number is a reason to bet.