docs: edge-shading challenger measured — flooding persists, input scale is the bug

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com> Claude-Session: https://claude.ai/code/session_01QJs13VsyiSKYQP6rj3NNmc
2026-07-31 00:39:51 -04:00
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@@ -516,3 +516,29 @@ below floor), 8 NULL with `null_despite_price = 0`; settled 1,163 and graded 1,2
 stamping one would record a model transition that never happened.

 312 suites / 3,890 tests green, web build exit 0.
+
+---
+
+# EDGE-SHADING CHALLENGER — built + measured 2026-07-31 → `specs/edge-shading-challenger.md`
+
+Challenger only; champion byte-identical; nothing promoted. The mechanic is sound and built
+(`adjusted = raw_edge × f(e)`, `f` bounded to (0,1], one fixed bar that never moves; same raw 6% edge
+→ **A** in soft `mlb:total_bases`, **B** in sharp `nba:points`, unit-proven).
+
+**But the measurement says the flooding is NOT fixed:** on 1,250 live rows the challenger grades
+**79.0% A / 80.9% A-or-B** (MLB 93.4% A) vs champion 0.2% A.
+
+**Why — two findings.** (1) **The shading is a no-op on the live board: 0 of 1,250 rows are actually
+shaded.** 96.5% are unscored (f=1) and the one scored market present is the anchor (f=1.0 by
+construction); `mlb:strikeouts` and `nba:points` are absent from the ledger entirely (our basketball is
+`wnba`). (2) **The input scale is the bug, not the placement.** Against a fixed 5% bar the RAW edge
+already clears A on 100% of MLB doubles and 89.6% of hits, with MLB's median raw edge at 60% — twelve
+times the bar. **Applying the sharpest score in the spec (f=0.647) to every row still leaves 75.8%
+clearing A.** A multiplier bounded ≤1 cannot close a 12× overshoot.
+
+`edge_pct` is a price-free `(proj−line)/line` gap whose scale is a function of line size — not a
+betting edge, so no fixed betting-edge bar is meaningful against it. **Unblocking needs the input
+replaced (`p_win` vs `fair_prob`, both already stored), not the multiply moved**, plus scores fit from
+our own record for the 9 of 11 live markets that have none.
+
+313 suites / 3,899 tests green, web build exit 0.