feat: name leftover-map rank on leftover pairs (v2.12.21)

AGENTS.md

@@ -186,12 +186,13 @@ in the same spirit) -- never against real data, per the hard rule above.
 against a live local stack (`make up`) and self-skip without one -- see
 [README.md](README.md#local-product-stack-docker-compose).
 
-Period leftover pairs (ADR 0017 / 0018) are computed in
+Period leftover pairs (ADR 0048 / 0049 / 0171) are computed in
 `lineageweave/leftover_pairs.py` from the residual after a real
 GRM/GPCM score, never invented. Missing cells stay out of the
 Gabriel factorization. Closest and farthest post–criterion pairs
-persist to `report_leftover_pair` and sit above the member list so
-a click opens that post.
+persist to `report_leftover_pair` with leftover-map rank so rank 0
+is not read as structure, and sit above the member list so a click
+opens that post.
 
 `frontend/` has its own toolchain (Node pinned via `frontend/mise.toml`,
 pnpm via Corepack -- do not add a second Node package manager or a

ARCHITECTURE.md

@@ -588,8 +588,8 @@ on those same fixed parameters (Kim, 2006 FIPC). After scoring,
 `information_polytomous` ranks the shared-bank items by Fisher
 information at the group's mean θ (Lord, 1980 max-info CAT). Rankings
 persist to `report_item_information`. After those IRT main effects,
-residual SVD leftover pairs (Jeon et al., 2021; ADR 0017) persist to
-`report_leftover_pair`. Results persist to
+residual SVD leftover pairs (Jeon et al., 2021; ADR 0048 / 0171) persist to
+`report_leftover_pair` with leftover-map rank. Results persist to
 `report_period_score` / `report_member_score`.
 `GET /api/reports/{grouping}` lists the trend;
 `GET /api/reports/{grouping}/{period}` is ABAC-filtered;
@@ -601,7 +601,8 @@ bank as the dummy high/low band rows, so comparison-strip click
 through opens those DAG posts. Report members include the earliest
 open ticket title, status lookup label, and due date when one exists. The home page renders
 the actual mean θ, the FIPC delta, the CAT-selected item, leftover
-closest/farthest pairs above the member list, and the
+closest/farthest pairs (leftover-map rank next to leftover-map
+distance `d`) above the member list, and the
 PU / corp / thread comparison -- never a placeholder. TEPP is unchanged.
 
 ## Phase 6b: Knowledge Graph as a real Ontology + Semantic Layer

CHANGELOG.d/2.12.21-leftover-map-rank.md

@@ -0,0 +1,8 @@
+## 2.12.21 — Leftover-map rank
+
+- Persist leftover-map rank on leftover post–criterion pairs (ADR 0171).
+  Rank is the number of Gabriel singular values above the floor. After
+  `make seed`, closest and farthest leftover pairs sit above the member
+  list with `rank {n}` next to leftover-map distance `d`; click opens
+  that post. Rank 0 names no leftover structure. Never invent a leftover
+  score or a theta.

CHANGELOG.md

@@ -12,6 +12,15 @@ All notable changes to this project are documented here. Format follows
   environment, so local OIDC and synthetic-data workflows resolve the same
   pinned dependencies as CI.
 
+## [2.12.21] - 2026-08-24
+
+### Added
+
+- Period leftover pair rows now name leftover-map rank after IRT main
+  effects next to leftover-map distance `d`, then open that post
+  (Jeon et al., 2021, eq. 3; ADR 0171). Rank 0 names no leftover
+  structure rather than inventing a leftover score.
+
 ## [2.12.6] - 2026-08-20
 
 ### Added

CLAUDE.md

@@ -54,7 +54,9 @@ chip name contains `Corporate entity: Demo Corp` and the persisted
 mean θ. The period-report panel says Demo Corp is the opened grouping
 and to read its mean θ and member posts, then open a post. Those
 members land immediately under that next action, ahead of Other Corp
-and the week strip. Opening Public post names the next action: read
+and the week strip. After `make seed`, leftover closest/farthest pairs
+sit above the member list with leftover-map rank; rank 0 names no
+leftover structure. Opening Public post names the next action: read
 Event Lineage, Keyman, and evaluation on that post. The popup Event
 Lineage DAG marks that post current. After that current node, the
 popup names Keyman and evaluation as the next read. After landed

backend/app/report_ingestion.py

@@ -443,8 +443,9 @@ async def persist_period_report(
             """
             insert into report_leftover_pair (
                 grouping_kind, grouping_key, period_code, rubric_version,
-                pair_kind, post_id, criterion_code, leftover_distance, leftover_residual
-            ) values ($1,$2,$3,$4,$5,$6,$7,$8,$9)
+                pair_kind, post_id, criterion_code, leftover_distance, leftover_residual,
+                leftover_map_rank
+            ) values ($1,$2,$3,$4,$5,$6,$7,$8,$9,$10)
             """,
             grouping_kind,
             grouping_key,
@@ -455,6 +456,7 @@ async def persist_period_report(
             pair.criterion_code,
             pair.leftover_distance,
             pair.leftover_residual,
+            pair.leftover_map_rank,
         )
 
 
@@ -601,7 +603,7 @@ async def fetch_period_reports(
     leftover = await conn.fetch(  # nosemgrep: python.lang.security.audit.sqli.asyncpg-sqli.asyncpg-sqli
         f"""
         select lp.grouping_key, lp.pair_kind, lp.post_id, lp.criterion_code,
-               lp.leftover_distance, lp.leftover_residual, p.post_title,
+               lp.leftover_distance, lp.leftover_residual, lp.leftover_map_rank, p.post_title,
                p.visibility_code, p.corporate_entity_id,
                ({_SOURCE_CONTEXT_PRESENT_SQL}) as has_real_source_context
         from report_leftover_pair lp
@@ -698,6 +700,11 @@ async def fetch_period_reports(
                         "criterion_code": str(row["criterion_code"]),
                         "leftover_distance": float(row["leftover_distance"]),
                         "leftover_residual": float(row["leftover_residual"]),
+                        "leftover_map_rank": (
+                            None
+                            if row["leftover_map_rank"] is None
+                            else int(row["leftover_map_rank"])
+                        ),
                         "visibility_code": row["visibility_code"],
                         "corporate_entity_id": str(row["corporate_entity_id"]),
                         "has_real_source_context": bool(row["has_real_source_context"]),

backend/tests/test_api.py

@@ -113,6 +113,11 @@
     / "migrations"
     / "0102_project_bound_summary_event.sql"
 )
+_LEFTOVER_MAP_RANK_MIGRATION = (
+    Path(__file__).resolve().parents[2]
+    / "migrations"
+    / "0171_report_leftover_map_rank.sql"
+)
 
 
 def _postgres_available() -> bool:
@@ -226,6 +231,7 @@ def seeded_db(demo_analyst_token):
             cur.execute(_MAJOR_EVENT_ACTION_MIGRATION.read_text())
             cur.execute(_PROJECT_BOUND_ACTION_MIGRATION.read_text())
             cur.execute(_PROJECT_BOUND_EVENT_MIGRATION.read_text())
+            cur.execute(_LEFTOVER_MAP_RANK_MIGRATION.read_text())
             cur.execute(
                 "insert into common_lookup_value (lookup_category, lookup_code, lookup_label) values "
                 "('corporate_entity_level', 'group', 'Group'), "
@@ -4518,6 +4524,8 @@ def test_seed_period_report_surfaces_on_get_reports(client, demo_analyst_token,
     assert leftover_kinds <= {"closest", "farthest"}
     assert all(pair["post_title"] for pair in high_report.get("leftover_pairs", []))
     assert all(pair["leftover_distance"] >= 0 for pair in high_report.get("leftover_pairs", []))
+    for pair in high_report.get("leftover_pairs", []):
+        assert pair["leftover_map_rank"] >= 0
 
     week3 = client.get(
         "/api/reports/process_unit/2026-W03",

docker/postgres-init/migrate.sh

@@ -19,6 +19,7 @@ for migration in /opt/lineageweave/migrations/*.sql; do
     case "$migration_name" in
         0012_*|0013_*|0014_*|0015_*|0016_*|0017_*|0018_*|0019_*|0020_*|0021_*|0022_*|0023_*|0024_*|0025_*|0026_*|0027_*|0028_*|0029_*|0030_*|0031_*|0032_*|0033_*|0034_*|0035_*|0036_*|0037_*|0038_*|0039_*|0040_*|0041_*|0042_*|0043_*|0044_*|0045_*|0046_*|0047_*|0048_*|0049_*|0050_*) ;;
         0060_*|0100_*|0101_*|0102_*) ;;
+        0171_*) ;;
         *) continue ;;
     esac
     printf 'Applying %s\n' "$migration_name"

docs/adr/0003-fast-mlsirm-report-integration.md

@@ -100,10 +100,11 @@ than one large PR:
    `information_polytomous` (Lord, 1980 max-info). Persist the ranking
    (`report_item_information`) and show the rank-1 item on the Period
    reports panel. Do not reimplement an information function here.
-7. **Leftover-pair slice** (shipped in 0.71.2; ADR 0017 / 0018): after
+7. **Leftover-pair slice** (shipped in 0.71.2; ADR 0048 / 0049 / 0171): after
    IRT main effects, persist closest and farthest post–criterion pairs
-   from the residual leftover map. Do not fork LSIRM; do not invent a
-   leftover-pair API inside `fast-mlsirm` in this slice.
+   from the residual leftover map, including leftover-map rank so a
+   rank-0 collapse is not read as leftover structure. Do not fork LSIRM;
+   do not invent a leftover-pair API inside `fast-mlsirm` in this slice.
 
 **TEPP boundary.** [ARCHITECTURE.md](../../ARCHITECTURE.md) already
 assigns calibrated temporal/event measurement to

docs/adr/0048-persist-lsirm-leftover-pairs.md

@@ -2,6 +2,7 @@
 
 **Decision status:** Accepted
 **Date:** 2026-08-17
+**Amended by:** [ADR 0171](0171-leftover-map-rank.md) (full map rank)
 
 ## Context
 
@@ -30,7 +31,10 @@ and one `farthest` observed cell per period report in
 `report_leftover_pair` (3NF, two-or-more-word `snake_case`).
 
 The biplot lives in `lineageweave/leftover_pairs.py` so leftover
-tests do not import `period_report` or `fast_mlsirm`.
+tests do not import `period_report` or `fast_mlsirm`. Each leftover
+row names leftover-map rank: the number of Gabriel singular values
+above the floor (ADR 0171). A rank-0 collapse still emits a stable
+pair; the stored rank is then `0`, not invented leftover structure.
 
 Cascade the rows with `report_period_score`. A leftover post must
 also be a `report_member_score` row, and the leftover criterion

docs/adr/0049-leftover-pair-report-ui.md

@@ -2,6 +2,7 @@
 
 **Decision status:** Accepted
 **Date:** 2026-08-17
+**Amended by:** [ADR 0171](0171-leftover-map-rank.md) (full map rank)
 
 ## Context
 
@@ -17,10 +18,14 @@ second navigation surface.
 
 On each period-report group, render leftover pairs **above** the
 member list. Each pair is a button: closest or farthest label, post
-title, criterion short label, leftover-map distance, and the next
-action (“Open this post to read the criterion it sat closest to /
-farthest from after main effects.”). Clicking the button opens that
-post with the same handler as a member row.
+title, criterion short label, leftover-map distance, leftover-map
+rank when the value is a finite non-negative integer, and the next
+action. Rank 0 next action: leftover map has no leftover structure
+after IRT main effects; open this post. Rank ≥ 1 next action: read
+leftover map rank after IRT main effects, then open this post.
+Missing rank omits the badge and keeps the closest/farthest action.
+Clicking the button opens that post with the same handler as a member
+row. Rank naming is [ADR 0171](0171-leftover-map-rank.md).
 
 After `make seed`, closest and farthest leftover pairs sit above the
 member list. Click a pair to open that post.

docs/adr/0171-leftover-map-rank.md

@@ -0,0 +1,71 @@
+# ADR 0171 — Name leftover-map rank on leftover pairs
+
+**Decision status:** Accepted
+**Date:** 2026-08-24
+
+Amends [ADR 0048](0048-persist-lsirm-leftover-pairs.md) and
+[ADR 0049](0049-leftover-pair-report-ui.md).
+
+## Context
+
+ADR 0048 already persists leftover-map distance and leftover residual
+`R = Y − E[Y|θ, item]` on `report_leftover_pair`. A rank-0 residual
+still emits a stable closest/farthest pair so `make seed` is not empty;
+the stored distance is then zero, not a fabricated interaction. ADR 0049
+renders those pairs above the member list. Without leftover-map rank, a
+buyer cannot tell a Gabriel biplot with leftover structure (Jeon et al.,
+2021, eq. 3) from an origin collapse that still shows `d 0.00`.
+
+This increment does not persist leftover-map coordinates, does not name
+observed `Y` / expected `E`, does not change leftover-map axis count, and
+does not land Post quality on the leftover criterion.
+
+The unprotected-stack ADR for the same buyer fact was 0164. This
+protected-main reconstruction uses **0171** so it does not collide with
+two-axis leftover-map distance (0166), leftover coverage (0168),
+leftover-map axis share (0169), or leftover observed Y / expected E
+(0170).
+
+## Decision
+
+Each leftover pair names `leftover_map_rank`: the number of Gabriel
+singular values above the leftover singular floor on the complete-case
+residual rectangle. Closest and farthest pairs on one period report share
+that rank. A fallback pair that is not placed on a leftover map stores
+rank `0`. Migration `0171` is the single source of the column on every
+install path; shipped migrations (`0001` / `0012`) are never rewritten.
+It adds a nullable column so older leftover rows keep distance and residual
+without fabricating a rank.
+
+The pair button shows `rank {n}` when the value is a finite
+non-negative integer. Rank `0` next action: leftover map has no leftover
+structure after IRT main effects; open this post. Rank `≥ 1` next action:
+read leftover map rank after IRT main effects, then open this post. Omit
+the rank badge when the value is missing. Do not invent a leftover score.
+Do not invent a theta.
+
+## Consequences
+
+`GET /api/reports/{grouping}/{period}` returns `leftover_map_rank`. After
+`make seed`, closest and farthest leftover pairs sit above the member
+list with leftover-map rank; click opens that post. Hidden posts stay
+hidden.
+
+## Related
+
+Independent of leftover interaction-map persistence, leftover-criterion
+evaluation landing, leftover residual UI extraction, leftover-map
+complete-case coverage, leftover-map axis share, leftover pairs on the
+grouping comparison strip, two-axis leftover-map distance, and leftover
+observed `Y` / expected `E`.
+
+## References
+
+Gabriel, K. R. (1971). The biplot graphic display of matrices with
+application to principal component analysis. *Biometrika, 58*(3),
+453–467. https://doi.org/10.1093/biomet/58.3.453
+
+Jeon, M., Jin, I. H., Schweinberger, M., & Baugh, S. (2021). Mapping
+unobserved item–respondent interactions: A latent space item response
+model with interaction map. *Psychometrika, 86*(2), 378–403.
+https://doi.org/10.1007/s11336-021-09762-5

frontend/package.json

@@ -1,7 +1,7 @@
 {
   "name": "frontend",
   "private": true,
-  "version": "2.12.6",
+  "version": "2.12.21",
   "type": "module",
   "scripts": {
     "dev": "vite",

frontend/src/App.test.tsx

@@ -932,6 +932,7 @@ describe("App, authenticated", () => {
                     criterion_code: "sales_lead_specificity",
                     leftover_distance: 0.12,
                     leftover_residual: 0.4,
+                    leftover_map_rank: 1,
                   },
                   {
                     pair_kind: "farthest",
@@ -940,6 +941,7 @@ describe("App, authenticated", () => {
                     criterion_code: "general_sentiment_negative",
                     leftover_distance: 1.84,
                     leftover_residual: -1.1,
+                    leftover_map_rank: 1,
                   },
                 ],
                 members: [
@@ -3357,13 +3359,15 @@ describe("App, authenticated", () => {
     });
     expect(closestPair).toHaveTextContent("Closest leftover: Public post · sales-lead");
     expect(closestPair).toHaveTextContent(
-      "Open this post to read the criterion it sat closest to after main effects.",
+      "Leftover map rank 1 after IRT main effects. Open this post.",
     );
+    expect(closestPair).toHaveTextContent("rank 1");
     expect(closestPair).toHaveTextContent("d 0.12");
     expect(farthestPair).toHaveTextContent("Farthest leftover: Specification revision requested · negative");
     expect(farthestPair).toHaveTextContent(
-      "Open this post to read the criterion it sat farthest from after main effects.",
+      "Leftover map rank 1 after IRT main effects. Open this post.",
     );
+    expect(farthestPair).toHaveTextContent("rank 1");
     expect(farthestPair).toHaveTextContent("d 1.84");
     const memberButton = screen.getByRole("button", { name: /open report post: public post/i });
     expect(closestPair.compareDocumentPosition(memberButton) & Node.DOCUMENT_POSITION_FOLLOWING).toBeTruthy();

frontend/src/App.tsx

@@ -102,6 +102,7 @@ import {
   useLocale,
 } from "./i18n";
 import { rememberOidcReturnUrl, returnUrlFromLocation } from "./oidcReturnUrl";
+import { formatLeftoverMapRank, LEFTOVER_RANK_STRUCTURE_ACTION, LEFTOVER_RANK_ZERO_ACTION } from "./leftoverMapRank";
 import "./App.css";
 
 function orchestratorUnavailableMessage(err: unknown, action: string): string {
@@ -3394,10 +3395,17 @@ function ReportsPanel({
                 {report.leftover_pairs.map((pair) => {
                   const kindLabel =
                     pair.pair_kind === "farthest" ? "Farthest leftover" : "Closest leftover";
+                  const rankBadge = formatLeftoverMapRank(pair.leftover_map_rank);
                   const nextAction =
-                    pair.pair_kind === "farthest"
-                      ? "Open this post to read the criterion it sat farthest from after main effects."
-                      : "Open this post to read the criterion it sat closest to after main effects.";
+                    rankBadge !== null
+                      ? pair.leftover_map_rank === 0
+                        ? t(LEFTOVER_RANK_ZERO_ACTION)
+                        : tf(LEFTOVER_RANK_STRUCTURE_ACTION, {
+                            rank: String(pair.leftover_map_rank),
+                          })
+                      : pair.pair_kind === "farthest"
+                        ? t("Open this post to read the criterion it sat farthest from after main effects.")
+                        : t("Open this post to read the criterion it sat closest to after main effects.");
                   const criterion = criterionShortLabel(pair.criterion_code);
                   return (
                     <li
@@ -3413,6 +3421,7 @@ function ReportsPanel({
                           {kindLabel}: {pair.post_title} · {criterion}
                         </span>
                         <span className="post-badge">{nextAction}</span>
+                        {rankBadge ? <span className="post-badge">{rankBadge}</span> : null}
                         <span className="post-badge">d {pair.leftover_distance.toFixed(2)}</span>
                       </button>
                     </li>

frontend/src/api.ts

@@ -759,6 +759,7 @@ export interface LeftoverPair {
   criterion_code: string;
   leftover_distance: number;
   leftover_residual: number;
+  leftover_map_rank?: number | null;
 }
 
 export interface PeriodGroupReport {