seonghobae · Aug 24, 2026 · Aug 23, 2026 · Aug 23, 2026 · Aug 23, 2026 · Aug 23, 2026
diff --git a/AGENTS.md b/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
-`lineageweave/leftover_pairs.py` from the residual after a real
-GRM/GPCM score, never invented. Missing cells stay out of the
+Period leftover pairs (ADR 0017 / 0018 / 0048 / 0049 / 0177) 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 observed `Y` and expected
+`E[Y|θ, item]` so residual reconciles to `Y − E`, 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

diff --git a/ARCHITECTURE.md b/ARCHITECTURE.md
@@ -588,8 +588,9 @@ 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 0017 / 0048 / 0177)
+persist to `report_leftover_pair` with observed `Y` and expected
+`E[Y|θ, item]`. 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 +602,8 @@ 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 (observed `Y` and expected `E` after IRT main
+effects plus 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

diff --git a/CHANGELOG.d/2.12.20-leftover-observed-expected.md b/CHANGELOG.d/2.12.20-leftover-observed-expected.md
@@ -0,0 +1,8 @@
+## 2.12.20 — Leftover observed Y and expected E
+
+- Persist observed `Y` and expected `E[Y|θ, item]` on leftover
+  post–criterion pairs (ADR 0177). Residual stays `R = Y − E`. After
+  `make seed`, closest and farthest leftover pairs sit above the member
+  list with `Y` and `E` next to leftover-map distance `d`; click opens
+  that post. Omit the badge when either value is missing. Never invent
+  a leftover score or a theta.
diff --git a/CHANGELOG.d/2.12.21-leftover-map-rank.md b/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 0172).
+  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.
diff --git a/CHANGELOG.d/2.12.22-leftover-residual-disclosure.md b/CHANGELOG.d/2.12.22-leftover-residual-disclosure.md
@@ -0,0 +1,7 @@
+## 2.12.22 — Leftover residual disclosure
+
+- Name signed leftover residual `R = Y − E[Y|θ, item]` on leftover
+  post–criterion pair rows (ADR 0178). After `make seed`, closest and
+  farthest leftover pairs sit above the member list with `R` next to
+  leftover-map distance `d`; click opens that post. A non-finite
+  residual is an em dash, never a fabricated leftover score.
diff --git a/CHANGELOG.md b/CHANGELOG.md
@@ -203,6 +203,34 @@ All notable changes to this project are documented here. Format follows
 - The static SQL review contract now counts the Customer Master evidence query
   that uses closed schema fragments and bound entity ids.
 
+## [2.12.20] - 2026-08-24
+
+### Added
+
+- Period leftover pair rows now name observed `Y` and expected
+  `E[Y|θ, item]` after IRT main effects next to leftover-map distance
+  `d`, then open that post (Jeon et al., 2021, eq. 3; ADR 0177). Residual
+  stays `R = Y − E`. Missing or non-finite `Y` / `E` omit the badge
+  rather than inventing a leftover score.
+
+## [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 0172). Rank 0 names no leftover
+  structure rather than inventing a leftover score.
+
+## [2.12.22] - 2026-08-24
+
+### Added
+
+- Period leftover pair rows now name signed leftover residual
+  `R = Y − E[Y|θ, item]` next to leftover-map distance `d`, then open
+  that post (Jeon et al., 2021, eq. 3; ADR 0178). A non-finite residual
+  is an em dash rather than a fabricated leftover score.
+
 ## [2.12.6] - 2026-08-20
 
 ### Added

diff --git a/CLAUDE.md b/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. Leftover closest/farthest pairs name observed `Y`
+and expected `E` after IRT main effects next to leftover-map distance
+`d`; click a pair to open that post. 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

diff --git a/backend/app/report_ingestion.py b/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,
+                observed_response, expected_response, leftover_map_rank
+            ) values ($1,$2,$3,$4,$5,$6,$7,$8,$9,$10,$11,$12)
             """,
             grouping_kind,
             grouping_key,
@@ -455,6 +456,9 @@ async def persist_period_report(
             pair.criterion_code,
             pair.leftover_distance,
             pair.leftover_residual,
+            pair.observed_response,
+            pair.expected_response,
+            pair.leftover_map_rank,
         )
 
 
@@ -602,7 +606,8 @@ 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.observed_response, lp.expected_response, lp.leftover_map_rank, p.post_title,
                p.visibility_code, p.corporate_entity_id,
                p.author_account_id, p.source_detail_state_code,
                ({_SOURCE_CONTEXT_PRESENT_SQL}) as has_real_source_context
@@ -702,6 +707,21 @@ async def fetch_period_reports(
                         "criterion_code": str(row["criterion_code"]),
                         "leftover_distance": float(row["leftover_distance"]),
                         "leftover_residual": float(row["leftover_residual"]),
+                        "observed_response": (
+                            None
+                            if row["observed_response"] is None
+                            else float(row["observed_response"])
+                        ),
+                        "expected_response": (
+                            None
+                            if row["expected_response"] is None
+                            else float(row["expected_response"])
+                        ),
+                        "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"]),
                         "author_account_id": str(row["author_account_id"]),

diff --git a/backend/tests/test_api.py b/backend/tests/test_api.py
@@ -5677,6 +5677,12 @@ 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", []):
+        observed = pair.get("observed_response")
+        expected = pair.get("expected_response")
+        if observed is None or expected is None:
+            continue
+        assert abs(pair["leftover_residual"] - (observed - expected)) < 1e-6
 
     week3 = client.get(
         "/api/reports/process_unit/2026-W03",

diff --git a/docker/postgres-init/migrate.sh b/docker/postgres-init/migrate.sh
@@ -18,7 +18,7 @@ for migration in /opt/lineageweave/migrations/*.sql; do
     migration_name=${migration##*/}
     case "$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_*|0103_*|0104_*|0105_*|0106_*|0107_*|0108_*|0109_*|0110_*|0111_*|0112_*|0113_*|0114_*|0130_*|0133_*|0134_*|0136_*|0137_*|0138_*|0139_*|0176_*) ;;
+        0060_*|0100_*|0101_*|0102_*|0103_*|0104_*|0105_*|0106_*|0107_*|0108_*|0109_*|0110_*|0111_*|0112_*|0113_*|0114_*|0130_*|0133_*|0134_*|0136_*|0137_*|0138_*|0139_*|0172_*|0176_*|0177_*) ;;
         *) continue ;;
     esac
     printf 'Applying %s\n' "$migration_name"

diff --git a/docs/adr/0003-fast-mlsirm-report-integration.md b/docs/adr/0003-fast-mlsirm-report-integration.md
@@ -103,10 +103,11 @@ 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 0017 / 0018 / 0048 / 0049 / 0177): 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, naming observed `Y` and expected
+   `E[Y|θ, item]` so residual reconciles to `Y − E`. 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

diff --git a/docs/adr/0048-persist-lsirm-leftover-pairs.md b/docs/adr/0048-persist-lsirm-leftover-pairs.md
@@ -2,6 +2,7 @@
 
 **Decision status:** Accepted
 **Date:** 2026-08-17
+**Amended by:** [ADR 0177](0177-leftover-observed-expected.md) (observed Y and expected E)
 
 ## Context
 
@@ -30,7 +31,9 @@ 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 also names observed `Y` and expected `E[Y|θ, item]` so residual
+reconciles to `Y − E` (ADR 0177).
 
 Cascade the rows with `report_period_score`. A leftover post must
 also be a `report_member_score` row, and the leftover criterion

diff --git a/docs/adr/0049-leftover-pair-report-ui.md b/docs/adr/0049-leftover-pair-report-ui.md
@@ -2,6 +2,7 @@
 
 **Decision status:** Accepted
 **Date:** 2026-08-17
+**Amended by:** [ADR 0177](0177-leftover-observed-expected.md) (observed Y and expected E)
 
 ## Context
 

diff --git a/docs/adr/0172-leftover-map-rank.md b/docs/adr/0172-leftover-map-rank.md
@@ -0,0 +1,71 @@
+# ADR 0172 — 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 **0172** so it does not collide with
+two-axis leftover-map distance (0166), leftover coverage (0168),
+leftover-map axis share (0148), leftover observed Y / expected E
+(0177), or analysis-run status same clock (0171).
+
+## 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 `0172` 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
diff --git a/docs/adr/0177-leftover-observed-expected.md b/docs/adr/0177-leftover-observed-expected.md
@@ -0,0 +1,76 @@
+# ADR 0177 — Persist observed Y and expected E 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`. ADR 0049 already
+renders closest and farthest pairs above the member list and opens the
+named post. Residual disclosure without naming `Y` and `E` leaves a
+reader unable to tell whether a leftover cell is a high observed
+response or a low expected category after IRT main effects.
+
+Jeon et al. (2021, eq. 3) leftover interaction is `−γ‖ξ_p − ζ_i‖`.
+Gabriel (1971) supplies the leftover-map coordinates from a residual
+biplot of `R`. `R` is not an invented leftover score: it is the
+observed category minus the already-fitted expected category. Those
+two inputs must travel with the pair row.
+
+This increment does not persist leftover-map coordinates, does not
+change leftover-map axis count, does not name complete-case coverage,
+and does not land Post quality on the leftover criterion.
+
+The unprotected-stack ADR for the same leftover-pair fact was 0163. This
+protected-main reconstruction uses **0177** so it does not collide
+with any current open-head ADR.
+
+## Decision
+
+Each leftover pair names:
+
+1. `observed_response` — the observed category `Y` for that
+   post–criterion cell;
+2. `expected_response` — `E[Y|θ, item]` from the already-fitted
+   GRM/GPCM main effects;
+3. `leftover_residual`, which must equal `Y − E` within `1e-6`.
+
+Migration `0177` is the single source of both columns on every
+install path, fresh or existing -- shipped migrations (`0001`/`0012`)
+are never edited after the fact. It adds them as nullable so older
+leftover rows keep distance and residual without fabricating `Y` or
+`E`. The pair button shows
+`Y {observed} · E {expected}` next to leftover-map distance `d` when
+both values are finite. The next action remains ADR 0049:
+`Open {post}, then read Post quality criterion {criterion}.` Omit the
+`Y` / `E` badge when either value is missing or non-finite. Do not
+invent a leftover score. Do not invent a theta.
+
+## Consequences
+
+`GET /api/reports/{grouping}/{period}` returns `observed_response`
+and `expected_response`. After `make seed`, closest and farthest
+leftover pairs sit above the member list with named `Y` and `E`;
+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, and two-axis leftover-map distance.
+
+## 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