Fix: the incumbent ruler respects the allow-list (correcting my own model)

My first delta run modelled the incumbent as first-row-wins over the RAW
feed and reported that an EXCLUDED book was "the market" on 69% of MLB
prop-lines, with prizepicks alone at 47%. That is WRONG and I caught it
before it went anywhere.

normalizeProps applies ALLOWED_BOOKS BEFORE gradeSlateService.dedupeProps
runs, so DFS books never reach the incumbent. The allow-list, for all the
coverage it costs, does keep DFS out of the ruler.

incumbentFairProb now takes the allow-list (defaulting to the live
ALLOWED_BOOKS) and reproduces the real chain. Two tests lock it, including
that a prop with no admitted book has NO incumbent -- it is never graded
at all, which is the real loss and is already measured as invisible_props.

Overstating the incumbent's badness would have been as dishonest as
understating it, and more persuasive.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01QJs13VsyiSKYQP6rj3NNmc

src/services/consensusRuler.js

@@ -124,15 +124,27 @@ function consensusFairProb(quotes, line, side, opts = {}) {
 }
 
 /**
- * CHALLENGER DELTA. The incumbent is "first row wins" — literally the first
+ * CHALLENGER DELTA — the incumbent, reproduced FAITHFULLY.
- * quote in feed order, whatever book that is. This reproduces it faithfully so
+ *
- * the comparison measures the real change and not an idealised one.
+ * The live chain is: PropLine -> `normalizeProps` (which applies the
+ * ALLOWED_BOOKS filter FIRST) -> `gradeSlateService.dedupeProps` (first row per
+ * player+stat+line wins). So the incumbent is the first quote from an ADMITTED
+ * book — not the first quote in the raw feed.
+ *
+ * This distinction is load-bearing and easy to get wrong in the alarming
+ * direction: ignoring the allow-list makes it look as though DFS pick'em has
+ * been pricing the model (prizepicks alone is 47% of raw first-rows). It has
+ * not — the allow-list, for all the coverage it costs, does keep DFS out of the
+ * incumbent. Overstating the incumbent's badness would be as dishonest as
+ * understating it.
  */
-function incumbentFairProb(quotes, line, side) {
+function incumbentFairProb(quotes, line, side, allowedBooks) {
   const want = String(side || 'over').toLowerCase() === 'under' ? 'under' : 'over';
   const target = num(line);
+  const allow = allowedBooks || require('../utils/oddsNormalizer').ALLOWED_BOOKS;
   for (const q of quotes || []) {
     if (!q || !q.book) continue;
+    if (allow && !allow.has(String(q.book).toLowerCase())) continue;
     if (target != null && num(q.line) !== target) continue;
     const over = num(q.over_odds);
     const under = num(q.under_odds);
@@ -150,7 +162,7 @@ function incumbentFairProb(quotes, line, side) {
 
 /** Both rulers plus the signed delta, for a single prop. */
 function compareRulers(quotes, line, side, opts = {}) {
-  const incumbent = incumbentFairProb(quotes, line, side);
+  const incumbent = incumbentFairProb(quotes, line, side, opts.allowedBooks);
   const consensus = consensusFairProb(quotes, line, side, opts);
   const delta = (incumbent.fair_prob != null && consensus.fair_prob != null)
     ? round4(consensus.fair_prob - incumbent.fair_prob)

src/services/proplineVerify.js

@@ -260,7 +260,7 @@ const REFERENCE_POLICIES = Object.freeze({
  * incumbent is first-row-wins, so it reports WHICH KIND of book has been acting
  * as "the market" — and DFS pick'em has the highest coverage in the feed.
  */
-function rulerDelta(raw) {
+function rulerDelta(raw, allowed) {
   const { compareRulers } = require('./consensusRuler');
   const { roleOf } = require('../config/bookRoles');
 
@@ -289,6 +289,7 @@ function rulerDelta(raw) {
 
   const deltas = [];
   const roleCounts = {};
+  let gradeable = 0;
   let consensusAvailable = 0;
   let bothAvailable = 0;
   let disagree2pts = 0;
@@ -296,9 +297,10 @@ function rulerDelta(raw) {
 
   for (const [key, quotes] of byPropLine.entries()) {
     const line = quotes[0].line;
-    const c = compareRulers(quotes, line, 'over');
+    const c = compareRulers(quotes, line, 'over', { allowedBooks: allowed });
     if (c.consensus.source === 'consensus') consensusAvailable += 1;
     if (c.incumbent.book) {
+      gradeable += 1;
       const r = roleOf(c.incumbent.book);
       roleCounts[r] = (roleCounts[r] || 0) + 1;
       roleCounts[`book:${c.incumbent.book}`] = (roleCounts[`book:${c.incumbent.book}`] || 0) + 1;
@@ -317,6 +319,8 @@ function rulerDelta(raw) {
 
   return {
     prop_line_groups: byPropLine.size,
+    gradeable_groups: gradeable,
+    gradeable_pct: byPropLine.size ? round2((100 * gradeable) / byPropLine.size) : null,
     consensus_available: consensusAvailable,
     consensus_available_pct: byPropLine.size ? round2((100 * consensusAvailable) / byPropLine.size) : null,
     comparable: bothAvailable,
@@ -435,7 +439,7 @@ async function verify(opts = {}) {
         continue;
       }
       out.per_sport[sport] = analyseBreadth(raw, allowed);
-      out.per_sport[sport].ruler_delta = rulerDelta(raw);
+      out.per_sport[sport].ruler_delta = rulerDelta(raw, allowed);
       const ev = raw.find((e) => e && e.id && Array.isArray(e.bookmakers) && e.bookmakers.length);
       if (ev) firstEvent[sport] = { id: ev.id, key: PA.SPORT_KEYS[sport] };
     } catch (err) {

tests/unit/consensusRuler.test.js

@@ -114,16 +114,26 @@ describe('consensusRuler — labelling and the median', () => {
 });
 
 describe('consensusRuler — the incumbent it is challenging', () => {
-  it('incumbent is literally first-row-wins, and that row can be a DFS book', () => {
+  const LIVE_ALLOWED = new Set(['draftkings', 'fanduel', 'betmgm', 'betrivers', 'pinnacle']);
-    const qs = [q('prizepicks', 1.5, -119, -119), q('novig', 1.5, -104, -104)];
+
-    const inc = incumbentFairProb(qs, 1.5, 'over');
+  it('incumbent is first-row-wins AMONG ADMITTED BOOKS — the allow-list runs first', () => {
-    expect(inc.book).toBe('prizepicks');
+    // normalizeProps applies ALLOWED_BOOKS before dedupeProps, so a DFS book
+    // sitting first in the raw feed is NOT the incumbent. Getting this wrong
+    // overstates the incumbent's badness, which is its own dishonesty.
+    const qs = [q('prizepicks', 1.5, -119, -119), q('betmgm', 1.5, -115, -105), q('draftkings', 1.5, -110, -110)];
+    const inc = incumbentFairProb(qs, 1.5, 'over', LIVE_ALLOWED);
+    expect(inc.book).toBe('betmgm');
     expect(inc.ruler_version).toBe(roles.RULER_V1);
   });
 
+  it('a prop with NO admitted book has no incumbent at all — it is never graded', () => {
+    const qs = [q('prizepicks', 1.5, -119, -119), q('novig', 1.5, -104, -104)];
+    expect(incumbentFairProb(qs, 1.5, 'over', LIVE_ALLOWED).fair_prob).toBeNull();
+  });
+
   it('compareRulers returns a signed delta in probability points', () => {
     const qs = [q('draftkings', 1.5, -140, 120), q('novig', 1.5, -104, -104), q('kalshi', 1.5, -103, -105)];
-    const c = compareRulers(qs, 1.5, 'over');
+    const c = compareRulers(qs, 1.5, 'over', { allowedBooks: LIVE_ALLOWED });
     expect(c.incumbent.book).toBe('draftkings');
     expect(c.consensus.source).toBe('consensus');
     expect(c.delta_pts).toBeLessThan(0);   // dk's favourite priced over above the exchanges
@@ -131,6 +141,6 @@ describe('consensusRuler — the incumbent it is challenging', () => {
   });
 
   it('delta is null when either side is unavailable — never 0', () => {
-    expect(compareRulers([q('prizepicks', 1.5, -119, -119)], 1.5, 'over').delta_pts).toBeNull();
+    expect(compareRulers([q('prizepicks', 1.5, -119, -119)], 1.5, 'over', { allowedBooks: LIVE_ALLOWED }).delta_pts).toBeNull();
   });
 });