diff --git a/AGENTS.md b/AGENTS.md
index ccf5a3160..ec76f877e 100644
--- a/AGENTS.md
+++ b/AGENTS.md
@@ -273,7 +273,7 @@ stops startup instead of leaving a healthy-looking partial schema, and
 application code must not compensate for a missing table.
 
 Period leftover pairs (ADR 0017 / 0018 / 0048 / 0049 / 0119 / 0158 / 0162 /
-0163 / 0164 / 0182 / 0185 / 0201 / 0233 / 0266 / 0267 / 0268 / 0269 / 0270 / 0271 / 0272 / 0273 / 0274 / 0275 / 0276 / 0277 / 0278 / 0279 / 0280 / 0281 / 0282 / 0283 / 0284 / 0285 / 0286 / 0287 / 0288 / 0289 / 0290 / 0291 / 0292 / 0293 / 0294 / 0295 / 0296 / 0297 / 0298 / 0299 / 0300 / 0301 / 0302 / 0303 / 0304 / 0305 / 0306 / 0307 / 0308 / 0309 / 0310 / 0311 / 0312 / 0313 / 0314 / 0315) are computed in `lineageweave/leftover_pairs.py` from the
+0163 / 0164 / 0182 / 0185 / 0201 / 0233 / 0266 / 0267 / 0268 / 0269 / 0270 / 0271 / 0272 / 0273 / 0274 / 0275 / 0276 / 0277 / 0278 / 0279 / 0280 / 0281 / 0282 / 0283 / 0284 / 0285 / 0286 / 0287 / 0288 / 0289 / 0290 / 0291 / 0292 / 0293 / 0294 / 0295 / 0296 / 0297 / 0298 / 0299 / 0300 / 0301 / 0302 / 0303 / 0304 / 0305 / 0306 / 0307 / 0308 / 0309 / 0310 / 0311 / 0312 / 0313 / 0314 / 0315 / 0316) are computed in `lineageweave/leftover_pairs.py` from the
 residual after a real GRM/GPCM score, never invented. Distances are
 Euclidean on the two-dimensional Gabriel leftover map; missing cells stay
 out of the factorization. Closest and farthest post–criterion pairs
@@ -591,6 +591,16 @@ and leftover-map comparison graphic incomplete items when those helpers return u
 leftover-map rank, leftover-map axis share, leftover-map post coverage, leftover-map item coverage,
 leftover-map incomplete post coverage, leftover-map incomplete item coverage, leftover pair
 count, or the count of unused axes.
+ADR 0316 captions leftover observed on that grouping comparison leftover-map
+graphic when formatLeftoverMapObserved returns a usable badge; a missing or
+non-finite `Y` omits that leftover-map comparison graphic leftover observed caption and keeps
+leftover residual `R`, leftover-map unexplained leftover `U`, leftover-map cross share `x`, leftover-map unexplained leftover share `s`, leftover-map explained leftover share `e`, leftover-map reconstruction `R̂`, leftover-map distance `d`, leftover-map comparison graphic coverage,
+leftover-map comparison graphic item coverage, leftover-map comparison graphic incomplete posts,
+and leftover-map comparison graphic incomplete items when those helpers return usable integers. Do not invent
+`Y` from `R` and `E`, leftover residual, leftover-map reconstruction, leftover-map unexplained leftover, leftover-map distance, plotted coordinates,
+leftover-map rank, leftover-map axis share, leftover-map post coverage, leftover-map item coverage,
+leftover-map incomplete post coverage, leftover-map incomplete item coverage, leftover pair
+count, or the count of unused axes.
 When `R`, `R̂`, `U`, `x`,
 `s`, and `e` are finite, `e + s + x = 1`. When `Y`, `E`, and `R` are
 finite, `Y − E = R`. When `R`, `R̂`, and `U` are
@@ -671,6 +681,9 @@ that grouping comparison leftover-map graphic with persisted leftover-map unexpl
 Grouping comparison leftover residual (ADR 0315) captions
 that grouping comparison leftover-map graphic with persisted leftover residual
 `R` when formatLeftoverMapResidual returns a usable badge.
+Grouping comparison leftover observed (ADR 0316) captions
+that grouping comparison leftover-map graphic with persisted leftover observed
+`Y` when formatLeftoverMapObserved returns a usable badge.
 Item complete-case coverage
 (ADR 0282) captions the leftover-map graphic with how many scored criteria
 entered the map. Item complete-case coverage on the pair list (ADR 0285)
diff --git a/ARCHITECTURE.md b/ARCHITECTURE.md
index 3f2860b71..c0cea1234 100644
--- a/ARCHITECTURE.md
+++ b/ARCHITECTURE.md
@@ -734,6 +734,9 @@ badge.
 ADR 0315 captions leftover residual on that grouping
 comparison leftover-map graphic when formatLeftoverMapResidual returns a usable
 badge.
+ADR 0316 captions leftover observed on that grouping
+comparison leftover-map graphic when formatLeftoverMapObserved returns a usable
+badge.
 Click a post marker or a pair button
 opens that post. Those ADRs are the normative mathematical, storage, and
 display contracts. Leftover-map axis share
@@ -778,7 +781,8 @@ graphic (ADR 0311), leftover-map unexplained leftover share on the grouping comp
 graphic (ADR 0312), leftover-map cross share on the grouping comparison leftover-map
 graphic (ADR 0313), leftover-map unexplained leftover on the grouping comparison leftover-map
 graphic (ADR 0314), leftover residual on the grouping comparison leftover-map
-graphic (ADR 0315);
+graphic (ADR 0315), leftover observed on the grouping comparison leftover-map
+graphic (ADR 0316);
 `POST .../rebuild` scores every grouping kind (post_admin). `make seed`
 folds A-100/B-200 Event Lineage fixtures (and the Riverbend calendar
 post) that already have constructed IRT cells into the same shared
diff --git a/CHANGELOG.d/2.73.0-leftover-map-compare-plot-observed.md b/CHANGELOG.d/2.73.0-leftover-map-compare-plot-observed.md
new file mode 100644
index 000000000..452dca111
--- /dev/null
+++ b/CHANGELOG.d/2.73.0-leftover-map-compare-plot-observed.md
@@ -0,0 +1,39 @@
+## 2.73.0 — Leftover observed on grouping comparison leftover-map graphic
+
+- Caption leftover observed on the grouping comparison leftover-map
+  graphic (ADR 0316). After `make seed`, closest and farthest leftover pairs
+  sit above the member list with the Gabriel biplot of already-named
+  coordinates, leftover-map axis share when finite, leftover-map complete-case
+  coverage when leftoverMapCoverageCounts returns usable complete-case integers,
+  leftover-map item complete-case coverage when leftoverMapItemCoverageCounts
+  returns usable complete-case integers, leftover-map incomplete post coverage
+  when leftoverMapIncompletePostCount returns a usable dropped integer,
+  leftover-map incomplete item coverage when leftoverMapIncompleteItemCount
+  returns a usable dropped integer, leftover-map reconstruction `R̂` when
+  formatLeftoverMapReconstruction returns a usable signed badge, leftover-map
+  explained leftover share `e` when formatLeftoverMapExplainedShare returns a
+  usable badge, leftover-map unexplained leftover share `s` when
+  formatLeftoverMapUnexplainedShare returns a usable badge, leftover-map
+  cross share `x` when formatLeftoverMapCrossShare returns a usable badge, leftover-map
+  unexplained leftover `U` when formatLeftoverMapUnexplained returns a usable badge, leftover residual
+  `R` when formatLeftoverMapResidual returns a usable badge, and leftover observed
+  `Y` on that grouping comparison leftover-map graphic; click a
+  post marker or a pair button opens that post. A missing or non-finite `Y`
+  omits that leftover-map comparison graphic leftover observed caption and keeps
+  leftover residual `R`, leftover-map unexplained leftover `U`, leftover-map cross share `x`, leftover-map unexplained leftover share `s`, leftover-map explained leftover
+  share `e`, leftover-map reconstruction `R̂`, leftover-map distance `d`, leftover-map
+  comparison graphic coverage, leftover-map comparison graphic item coverage,
+  leftover-map comparison graphic incomplete posts, and leftover-map comparison
+  graphic incomplete items when those helpers return usable integers. Rank-0 origin
+  cells still name `Y 0.00` when that persisted leftover observed is
+  finite. Comparison copy uses `leftover map comparison graphic leftover observed
+  {label}` so it stays distinct from `leftover observed
+  {label}` and from strip `Leftover map comparison observed`.
+  This increment does not caption leftover expected on the comparison graphic
+  with a distinct name. Do not invent `Y` from `R` and `E`, leftover residual, leftover-map reconstruction,
+  leftover-map unexplained leftover, leftover-map distance, plotted coordinates, leftover-map rank,
+  leftover-map axis share, leftover-map post coverage, leftover-map item coverage,
+  leftover-map incomplete post coverage, leftover-map incomplete item coverage,
+  leftover pair count, or the count of unused axes. A finite negative leftover
+  is shown, never clamped. Never invent a leftover score.
+  Never invent a theta. No new columns.
diff --git a/CHANGELOG.md b/CHANGELOG.md
index eacbaf474..3d22af526 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -8,6 +8,49 @@ All notable changes to this project are documented here. Format follows
 
 ### Added
 
+- Period leftover pairs now name leftover observed on the grouping
+  comparison leftover-map graphic (ADR 0316 / v2.73.0). After `make seed`,
+  closest and farthest leftover pairs sit above the member list with the
+  Gabriel biplot of already-named coordinates, leftover-map axis share when
+  finite, leftover-map complete-case coverage when leftoverMapCoverageCounts
+  returns usable complete-case integers, leftover-map item complete-case
+  coverage when leftoverMapItemCoverageCounts returns usable complete-case
+  integers, leftover-map incomplete post coverage when leftoverMapIncompletePostCount
+  returns a usable dropped integer, leftover-map incomplete item coverage when
+  leftoverMapIncompleteItemCount returns a usable dropped integer, leftover-map
+  reconstruction `R̂` when formatLeftoverMapReconstruction returns a usable signed
+  badge, leftover-map explained leftover share `e` when formatLeftoverMapExplainedShare
+  returns a usable badge, leftover-map unexplained leftover share `s` when
+  formatLeftoverMapUnexplainedShare returns a usable badge, leftover-map
+  cross share `x` when formatLeftoverMapCrossShare returns a usable badge, leftover-map
+  unexplained leftover `U` when formatLeftoverMapUnexplained returns a usable badge, leftover residual
+  `R` when formatLeftoverMapResidual returns a usable badge, and leftover observed
+  `Y` on that grouping comparison leftover-map graphic when
+  formatLeftoverMapObserved returns a usable badge; click a post marker or a pair
+  button opens that post. A missing or non-finite `Y` omits that leftover-map
+  comparison graphic leftover observed caption and keeps leftover residual
+  `R`, leftover-map unexplained leftover `U`, leftover-map cross share `x`, leftover-map unexplained leftover share `s`, leftover-map explained leftover
+  share `e`, leftover-map reconstruction `R̂`, leftover-map distance `d`, leftover-map
+  comparison graphic coverage, leftover-map comparison graphic item coverage,
+  leftover-map comparison graphic incomplete posts, and leftover-map comparison
+  graphic incomplete items when those helpers return usable integers. Rank-0 origin
+  cells still plot at `(0, 0)` and still name `Y 0.00` when that persisted leftover
+  observed is finite. Comparison copy uses `leftover map comparison graphic
+  leftover observed {label}` so it stays distinct from
+  `leftover observed {label}` and from strip `Leftover map comparison observed`.
+  Leftover observed omits independently of leftover residual,
+  leftover-map unexplained leftover, leftover-map cross share, leftover-map unexplained leftover share, leftover-map explained leftover share,
+  leftover-map reconstruction, leftover-map distance, and coverage notes. This
+  increment does not caption leftover expected on the comparison
+  graphic with a distinct name. Do not invent `Y` from `R` and `E`, leftover residual, leftover-map
+  reconstruction, leftover-map unexplained leftover, leftover-map distance, plotted coordinates,
+  leftover-map rank, leftover-map axis share, leftover expected,
+  leftover-map post coverage, leftover-map item coverage, leftover-map incomplete
+  post coverage, leftover-map incomplete item coverage, leftover pair count, or the
+  count of unused axes. A finite negative leftover is shown,
+  never clamped. Omit the comparison graphic when no leftover pair has four finite
+  leftover-map coordinates. Never invent a leftover score or a theta. No new columns.
+
 - Period leftover pairs now name leftover residual on the grouping
   comparison leftover-map graphic (ADR 0315 / v2.72.0). After `make seed`,
   closest and farthest leftover pairs sit above the member list with the
diff --git a/CLAUDE.md b/CLAUDE.md
index 6afe7c990..9f8bafce7 100644
--- a/CLAUDE.md
+++ b/CLAUDE.md
@@ -49,7 +49,7 @@ cutoff. Global Ask optional `knowledge_cutoff` uses the same cover
 
 Create/start endpoint rules (ADR 0017 / 0021), tie-vs-miss similarity
 (ADR 0026), R&R catalog ids (ADR 0019 / 0027), leftover pairs
-(ADR 0048–0164 / 0182 / 0185 / 0201 / 0233 / 0266 / 0267 / 0268 / 0269 / 0270 / 0271 / 0272 / 0273 / 0274 / 0275 / 0276 / 0277 / 0278 / 0279 / 0280 / 0281 / 0282 / 0283 / 0284 / 0285 / 0286 / 0287 / 0288 / 0289 / 0290 / 0291 / 0292 / 0293 / 0294 / 0295 / 0296 / 0297 / 0298 / 0299 / 0300 / 0301 / 0302 / 0303 / 0304 / 0305 / 0306 / 0307 / 0308 / 0309 / 0310 / 0311 / 0312 / 0313 / 0314 / 0315), occupational construct catalog search
+(ADR 0048–0164 / 0182 / 0185 / 0201 / 0233 / 0266 / 0267 / 0268 / 0269 / 0270 / 0271 / 0272 / 0273 / 0274 / 0275 / 0276 / 0277 / 0278 / 0279 / 0280 / 0281 / 0282 / 0283 / 0284 / 0285 / 0286 / 0287 / 0288 / 0289 / 0290 / 0291 / 0292 / 0293 / 0294 / 0295 / 0296 / 0297 / 0298 / 0299 / 0300 / 0301 / 0302 / 0303 / 0304 / 0305 / 0306 / 0307 / 0308 / 0309 / 0310 / 0311 / 0312 / 0313 / 0314 / 0315 / 0316), occupational construct catalog search
 (ADR 0257), the text-channel embedding swap and cosine
 clamp (ADR 0190), per-edge channel-score persistence (ADR 0195),
 token-backed status notices (ADR 0220),
diff --git a/docs/adr/0278-leftover-map-segment-observed.md b/docs/adr/0278-leftover-map-segment-observed.md
index c15d02b84..c3ef554f3 100644
--- a/docs/adr/0278-leftover-map-segment-observed.md
+++ b/docs/adr/0278-leftover-map-segment-observed.md
@@ -2,6 +2,8 @@
 
 **Decision status:** Accepted
 **Date:** 2026-08-30
+**Amended by:** [ADR 0316](0316-leftover-map-compare-plot-observed.md)
+(leftover observed on the grouping comparison leftover-map graphic)
 
 Amends [ADR 0268](0268-leftover-map-graphic-display.md),
 [ADR 0049](0049-leftover-pair-report-ui.md), and leftover observed `Y` /
diff --git a/docs/adr/0299-leftover-map-compare-observed.md b/docs/adr/0299-leftover-map-compare-observed.md
index 5fca58597..49126e6c2 100644
--- a/docs/adr/0299-leftover-map-compare-observed.md
+++ b/docs/adr/0299-leftover-map-compare-observed.md
@@ -3,6 +3,9 @@
 **Decision status:** Accepted
 **Date:** 2026-08-31
 
+**Amended by:** [ADR 0316](0316-leftover-map-compare-plot-observed.md)
+(leftover observed on the grouping comparison leftover-map graphic)
+
 Amends leftover pairs on the grouping comparison strip
 ([ADR 0149](0149-leftover-pairs-on-comparison-strip.md)), leftover observed `Y` /
 expected `E` ([ADR 0163](0163-leftover-observed-expected.md)), leftover observed on
diff --git a/docs/adr/0315-leftover-map-compare-plot-residual.md b/docs/adr/0315-leftover-map-compare-plot-residual.md
index a770fc040..57c36f7f8 100644
--- a/docs/adr/0315-leftover-map-compare-plot-residual.md
+++ b/docs/adr/0315-leftover-map-compare-plot-residual.md
@@ -3,6 +3,9 @@
 **Decision status:** Accepted
 **Date:** 2026-08-31
 
+**Amended by:** [ADR 0316](0316-leftover-map-compare-plot-observed.md)
+(leftover observed on the grouping comparison leftover-map graphic)
+
 Amends leftover residual on graphic-display pair segments
 ([ADR 0277](0277-leftover-map-segment-residual.md)), leftover residual
 on grouping comparison strip pair rows
diff --git a/docs/adr/0316-leftover-map-compare-plot-observed.md b/docs/adr/0316-leftover-map-compare-plot-observed.md
new file mode 100644
index 000000000..4e10a3945
--- /dev/null
+++ b/docs/adr/0316-leftover-map-compare-plot-observed.md
@@ -0,0 +1,254 @@
+# ADR 0316 — Name leftover observed on the grouping comparison leftover-map graphic
+
+**Decision status:** Accepted
+**Date:** 2026-08-31
+
+Amends leftover observed on graphic-display pair segments
+([ADR 0278](0278-leftover-map-segment-observed.md)), leftover observed
+on grouping comparison strip pair rows
+([ADR 0299](0299-leftover-map-compare-observed.md)), leftover residual
+on the grouping comparison leftover-map graphic
+([ADR 0315](0315-leftover-map-compare-plot-residual.md)), leftover-map
+unexplained leftover on the grouping comparison leftover-map graphic
+([ADR 0314](0314-leftover-map-compare-plot-unexplained-leftover.md)), leftover-map
+cross share on the grouping comparison leftover-map graphic
+([ADR 0313](0313-leftover-map-compare-plot-cross-share.md)), leftover-map
+unexplained leftover share on the grouping comparison leftover-map graphic
+([ADR 0312](0312-leftover-map-compare-plot-unexplained-share.md)), leftover-map
+explained leftover share on the grouping comparison leftover-map graphic
+([ADR 0311](0311-leftover-map-compare-plot-explained-share.md)), leftover-map
+reconstruction on the grouping comparison leftover-map graphic
+([ADR 0310](0310-leftover-map-compare-plot-reconstruction.md)), leftover-map
+incomplete item coverage on the grouping comparison leftover-map graphic
+([ADR 0309](0309-leftover-map-compare-plot-incomplete-item.md)), leftover-map
+incomplete post coverage on the grouping comparison leftover-map graphic
+([ADR 0308](0308-leftover-map-compare-plot-incomplete-post.md)), leftover-map item
+complete-case coverage on the grouping comparison leftover-map graphic
+([ADR 0307](0307-leftover-map-compare-plot-item-coverage.md)), leftover-map
+complete-case coverage on the grouping comparison leftover-map graphic
+([ADR 0306](0306-leftover-map-compare-plot-coverage.md)), leftover-map axis share
+on the grouping comparison leftover-map graphic
+([ADR 0305](0305-leftover-map-compare-plot-axis-share.md)), leftover-map graphic
+display on the grouping comparison strip
+([ADR 0304](0304-leftover-map-compare-graphic.md)), leftover observed `Y` /
+expected `E` ([ADR 0163](0163-leftover-observed-expected.md)), leftover pairs on
+the grouping comparison strip
+([ADR 0149](0149-leftover-pairs-on-comparison-strip.md)), leftover residual
+on grouping comparison strip pair rows
+([ADR 0298](0298-leftover-map-compare-residual.md)), leftover residual
+disclosure ([ADR 0162](0162-leftover-residual-disclosure.md)), leftover-map
+coordinates on the compare leftover-pair payload
+([ADR 0303](0303-leftover-map-compare-coordinates-payload.md)), leftover-map
+coordinates on grouping comparison strip pair rows
+([ADR 0302](0302-leftover-map-compare-coordinates.md)), leftover-map
+rank on grouping comparison strip pair rows
+([ADR 0301](0301-leftover-map-compare-rank.md)), leftover expected on grouping
+comparison strip pair rows
+([ADR 0300](0300-leftover-map-compare-expected.md)), leftover-map unexplained leftover
+on grouping comparison strip pair rows
+([ADR 0297](0297-leftover-map-compare-unexplained.md)), leftover-map unexplained leftover persistence
+([ADR 0182](0182-leftover-map-unexplained.md)), leftover-map rank
+([ADR 0164](0164-leftover-map-rank.md)), leftover-map rank on pair
+segments ([ADR 0280](0280-leftover-map-segment-rank.md)), leftover-map coordinate ticks
+([ADR 0270](0270-leftover-map-coordinate-ticks.md)), leftover-map graphic display
+([ADR 0268](0268-leftover-map-graphic-display.md)), leftover-map axis share on
+the graphic display ([ADR 0269](0269-leftover-map-axis-share-plot.md)), leftover-map
+complete-case coverage on the graphic display
+([ADR 0281](0281-leftover-map-plot-coverage.md)), leftover-map item complete-case
+coverage on the graphic display
+([ADR 0282](0282-leftover-map-plot-item-coverage.md)), leftover-map incomplete
+post coverage on the graphic display
+([ADR 0283](0283-leftover-map-plot-incomplete.md)), leftover-map incomplete
+item coverage on the graphic display
+([ADR 0284](0284-leftover-map-plot-incomplete-item.md)), leftover-map reconstruction
+on pair segments ([ADR 0272](0272-leftover-map-segment-reconstruction.md)), leftover-map
+reconstruction persistence ([ADR 0201](0201-leftover-map-reconstruction.md)), leftover-map
+explained leftover share persistence ([ADR 0266](0266-leftover-map-explained-share.md)), leftover-map unexplained leftover share persistence
+([ADR 0233](0233-leftover-map-unexplained-share.md)), leftover-map unexplained leftover share on pair segments
+([ADR 0274](0274-leftover-map-segment-unexplained-share.md)), leftover-map explained leftover share on pair segments
+([ADR 0273](0273-leftover-map-segment-explained-share.md)), leftover-map cross share on pair segments
+([ADR 0275](0275-leftover-map-segment-cross-share.md)), leftover-map cross share persistence
+([ADR 0185](0185-leftover-map-cross-share.md)), leftover-map cross share on grouping comparison strip pair rows
+([ADR 0296](0296-leftover-map-compare-cross-share.md)), leftover-map unexplained leftover on pair segments
+([ADR 0276](0276-leftover-map-segment-unexplained-leftover.md)), leftover residual on pair
+segments ([ADR 0277](0277-leftover-map-segment-residual.md)), leftover expected on pair
+segments ([ADR 0279](0279-leftover-map-segment-expected.md)), leftover-map distance on pair segments
+([ADR 0271](0271-leftover-map-segment-distance.md)), and leftover-map coordinates
+([ADR 0267](0267-leftover-map-coordinates.md)). Independent of leftover-map
+post complete-case coverage fail-closed on the pair list
+([ADR 0288](0288-leftover-map-list-post-coverage-helper.md)), leftover-map
+incomplete item coverage on the pair list
+([ADR 0287](0287-leftover-map-list-incomplete-item.md)), leftover-map incomplete
+post coverage on the pair list
+([ADR 0286](0286-leftover-map-list-incomplete-post.md)), leftover-map item
+complete-case coverage on the pair list
+([ADR 0285](0285-leftover-map-list-item-coverage.md)), and leftover expected
+on the grouping comparison leftover-map graphic.
+
+## Context
+
+ADR 0163 already persists leftover observed `Y` after IRT main effects.
+ADR 0278 already captions period-report leftover-map pair segments with
+`leftover observed {label}` when that leftover observed is finite.
+ADR 0299 already captions grouping comparison leftover-pair buttons with
+that same persisted leftover observed under accessible name
+`Leftover map comparison observed`. ADR 0315 already captions leftover residual
+on the grouping comparison leftover-map graphic. The comparison graphic still
+reuses hyphen `leftover observed {label}`, so a buyer who compares leftover
+pairs can treat the period-report graphic caption as the comparison graphic
+leftover observed even after the strip names `Y`. Hiding a distinct
+comparison-graphic leftover observed caption lets leftover residual `R` or
+leftover expected `E` be read as leftover observed without a next action.
+When `Y`, `E`, and `R` are finite, `Y − E = R`; the comparison graphic must
+name the same persisted `Y` the pair row and strip already show. A finite
+negative leftover is shown, never clamped.
+
+This increment captions leftover observed on the grouping comparison leftover-map
+graphic from already-named leftover observed through formatLeftoverMapObserved.
+Comparison copy uses the accessible name `leftover map comparison graphic leftover observed {label}`
+so it stays distinct from hyphen `leftover observed {label}` on the period-report
+graphic and from strip `Leftover map comparison observed`. It does not add
+columns. It does not recompute leftover observed from `R` and `E`, leftover residual,
+leftover-map reconstruction, leftover-map unexplained leftover, leftover-map
+distance, plotted coordinates, leftover-map rank, leftover-map axis share,
+leftover-map post coverage, leftover-map item coverage, leftover-map incomplete
+post coverage, leftover-map incomplete item coverage, leftover pair count, or the
+count of unused axes. Do not invent a leftover score. Do not invent a theta.
+
+The dashboard stack already used neighbouring leftover facts under other
+numbers. This protected increment uses **0316** so it does not collide with
+leftover residual on the grouping comparison leftover-map graphic
+(0315), leftover-map unexplained leftover on the grouping comparison leftover-map graphic
+(0314), leftover observed on grouping comparison strip pair rows (0299), leftover
+observed on pair segments (0278), leftover observed `Y` / expected `E` (0163), leftover-map
+graphic display (0268), leftover-map coordinates (0267), or the dashboard stacks.
+
+## Decision
+
+On the grouping comparison leftover-map graphic, caption each pair segment
+with persisted leftover observed when formatLeftoverMapObserved returns a usable
+badge, next to leftover residual `R`. Use the distinct accessible
+name `leftover map comparison graphic leftover observed {label}` so the graphic caption is
+not the strip badge (`Leftover map comparison observed`) and is not the
+period-report graphic caption (`leftover observed {label}`). A missing or
+non-finite `Y` omits that leftover-map comparison graphic leftover observed caption and
+keeps leftover residual `R` when formatLeftoverMapResidual
+returns a usable badge, leftover-map unexplained leftover `U` when formatLeftoverMapUnexplained
+returns a usable badge, leftover-map cross share `x` when
+formatLeftoverMapCrossShare returns a usable badge, leftover-map unexplained leftover share `s` when
+formatLeftoverMapUnexplainedShare returns a usable badge, leftover-map explained leftover share `e` when
+formatLeftoverMapExplainedShare returns a usable badge, leftover-map reconstruction `R̂` when
+formatLeftoverMapReconstruction returns a usable signed badge, leftover-map distance `d`, leftover map comparison
+axis share when finite, leftover map comparison axis text, leftover-map comparison
+graphic coverage when leftoverMapCoverageCounts returns usable complete-case
+integers, leftover-map comparison graphic item coverage when leftoverMapItemCoverageCounts
+returns usable complete-case integers, leftover-map comparison graphic incomplete
+posts when leftoverMapIncompletePostCount returns a usable dropped integer,
+leftover-map comparison graphic incomplete items when leftoverMapIncompleteItemCount
+returns a usable dropped integer, leftover-map rank when that rank is a non-negative
+integer, leftover expected `E` when finite, leftover residual `R` when finite,
+leftover-map reconstruction `R̂` when finite, leftover-map distance `d`, plus the
+strip leftover observed badge. Rank-0 origin cells still name `Y 0.00` when that
+persisted leftover observed is finite. A finite negative leftover is shown, never
+clamped. Do not invent `Y` from `R` and `E`, leftover residual, leftover-map
+reconstruction, leftover-map unexplained leftover, leftover-map distance, plotted
+coordinates, leftover-map rank, leftover-map axis share, leftover-map post
+coverage, leftover-map item coverage, leftover-map incomplete post coverage,
+leftover-map incomplete item coverage, leftover pair count, or the count of unused
+axes. Click a post marker to open that post.
+
+Leftover observed omits independently of leftover residual captions,
+leftover-map unexplained leftover captions, leftover-map cross share captions,
+unexplained leftover share captions, explained leftover share captions, reconstruction captions,
+coverage notes, and leftover-map distance. A missing leftover observed omits leftover-map
+comparison graphic leftover observed and keeps a usable leftover residual caption, a usable leftover-map unexplained leftover caption, a usable leftover-map cross share caption, a usable unexplained leftover share caption, a usable explained leftover share caption, a usable reconstruction caption, a usable
+distance caption, a usable post caption, a usable item caption, a usable incomplete
+posts caption, and a usable incomplete items caption.
+
+This increment does not caption leftover expected `E` on the comparison graphic
+with a distinct comparison-graphic name. That leftover expected already sits on
+the strip through ADR 0300. A finite negative leftover on neighbouring fields is shown,
+never clamped.
+
+Do not add SQL migrations. Do not edit shipped migrations. Do not persist inner
+product, cosine, or length as separate columns. Do not invent a leftover
+score. Do not invent a theta.
+
+## Consequences
+
+After `make seed`, grouping comparison leftover pairs that already show
+the leftover-map graphic of persisted `ξ` / `ζ` also name leftover observed
+on that graphic when formatLeftoverMapObserved returns a usable badge. Rank-0
+unused axes still plot at the origin and still name `Y 0.00` when that persisted
+leftover observed is finite. Click a post marker or a pair button opens that post.
+Hidden posts stay hidden. When `Y`, `E`, and `R` are finite, `Y − E = R`. When
+`R`, `R̂`, and `U` are finite, `U + R̂ = R`. When `R`, `R̂`, `U`, `x`, `s`, and
+`e` are finite, `e + s + x = 1`. When coordinates, reconstruction, and distance
+are finite, `R̂ = ξ · ζ` and `d = ‖ξ − ζ‖`.
+
+## Related
+
+Independent of leftover interaction-map persistence, leftover-criterion
+evaluation landing, leftover residual disclosure, leftover-map
+complete-case coverage persistence, leftover pairs on the grouping comparison
+strip, leftover-map complete-case coverage on the grouping comparison strip,
+leftover-map item complete-case coverage on the grouping comparison strip,
+leftover-map incomplete post coverage on the grouping comparison strip,
+leftover-map incomplete item coverage on the grouping comparison strip,
+leftover-map reconstruction on grouping comparison strip pair rows,
+leftover-map explained leftover share on grouping comparison strip pair rows,
+leftover-map unexplained leftover share on grouping comparison strip pair rows,
+leftover-map unexplained leftover on grouping comparison strip pair rows,
+leftover residual on grouping comparison strip pair rows, leftover observed
+on grouping comparison strip pair rows, leftover expected on grouping
+comparison strip pair rows, leftover-map rank on grouping comparison strip
+pair rows, leftover-map coordinates on grouping comparison strip pair rows,
+leftover-map coordinates on the compare leftover-pair payload, leftover-map
+inner product, leftover-map cosine, leftover-map length, leftover residual
+on pair segments, leftover observed on pair segments, leftover expected on
+pair segments, leftover-map rank on pair segments, leftover-map unexplained
+leftover on pair segments, leftover-map unexplained leftover persistence,
+leftover-map unexplained leftover share on pair segments, leftover-map unexplained leftover share
+persistence, leftover-map explained leftover
+share on pair segments, leftover-map explained leftover share
+persistence, leftover-map reconstruction on pair segments, leftover-map
+reconstruction persistence, leftover-map reconstruction on the grouping
+comparison leftover-map graphic, leftover-map explained leftover share on the grouping
+comparison leftover-map graphic, leftover-map unexplained leftover share on the grouping
+comparison leftover-map graphic, leftover-map cross share on the grouping
+comparison leftover-map graphic, leftover-map unexplained leftover on the grouping
+comparison leftover-map graphic, leftover residual on the grouping
+comparison leftover-map graphic, leftover-map item complete-case coverage on the
+graphic display, leftover-map item complete-case coverage on the pair list,
+leftover-map incomplete post coverage on the graphic display, leftover-map
+incomplete post coverage on the pair list, leftover-map incomplete item
+coverage on the graphic display, leftover-map incomplete item coverage on
+the pair list, leftover-map post complete-case coverage fail-closed on the
+pair list, leftover-map rank persistence, leftover-map coordinate
+persistence, leftover-map coordinate ticks, leftover-map complete-case
+coverage on the graphic display, leftover-map complete-case coverage on the
+grouping comparison leftover-map graphic, leftover-map item complete-case
+coverage on the grouping comparison leftover-map graphic, leftover-map
+incomplete post coverage on the grouping comparison leftover-map graphic,
+leftover-map incomplete item coverage on the grouping comparison leftover-map
+graphic, leftover-map axis share on the grouping comparison leftover-map graphic,
+and leftover expected on the grouping comparison leftover-map graphic.
+
+## References
+
+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
+(LSIRM interaction `−γ‖ξ_j − ζ_i‖` after main effects
+`α_j − β_i`; typically `p = 2` for the interaction map. Leftover observed of
+the leftover cell is the persisted category `Y` after IRT main effects.
+Grouping comparison leftover observed captions that persisted leftover on the
+grouping comparison leftover-map graphic only when formatLeftoverMapObserved
+returns a usable badge. Rank-0 unused axes still name `Y 0.00` when that leftover
+observed is stored. A finite negative leftover is shown, never clamped.
+When finite, `Y − E = R`.)
+
+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
diff --git a/docs/product-technical-gap-baseline.md b/docs/product-technical-gap-baseline.md
index 5594209eb..56ea640bd 100644
--- a/docs/product-technical-gap-baseline.md
+++ b/docs/product-technical-gap-baseline.md
@@ -1,5 +1,24 @@
 # Product & Technical Gap Baseline
 
+> Exact-head loop overlay: 2026-08-31 08:45 KST. Protected `main` is
+> `cb187cadee5fb6c46d8a944815ccc154a1e028d1`. Writes work. Do not
+> self-approve. #855 leftover residual on the grouping comparison leftover-map
+> graphic (v2.72.0 / ADR 0315) is `1087b16`, stacked on #854 @ `935cdea`. Independent
+> APPROVE is missing. Next buyer increment on this
+> cycle: leftover observed on the grouping comparison leftover-map
+> graphic (ADR 0316 / v2.73.0) delivered locally on
+> `feat/leftover-map-compare-plot-observed-v2730`. Caption persisted leftover observed
+> `Y` on that comparison graphic from already-named observed_response. Distinct
+> accessible name `leftover map comparison graphic leftover observed {label}`. Omit when
+> formatLeftoverMapObserved fail-closes. Do not caption leftover expected on that
+> comparison graphic with a distinct name this increment. Do not invent `Y` from
+> `R` and `E`, leftover residual, leftover-map reconstruction, leftover-map unexplained leftover,
+> leftover-map distance, plotted coordinates, leftover-map rank, leftover-map axis share,
+> leftover-map post coverage, leftover-map item coverage, leftover-map incomplete post coverage,
+> leftover-map incomplete item coverage, leftover pair count, or the count of unused
+> axes. Stack onto #855. Leave open for independent review. Do not squash-merge. Do not
+> self-approve. Issues #79 and #87 stay open. Do not merge #808 without independent APPROVE.
+
 > Exact-head loop overlay: 2026-08-31 08:20 KST. Protected `main` is
 > `cb187cadee5fb6c46d8a944815ccc154a1e028d1`. Writes work. Do not
 > self-approve. #854 leftover-map unexplained leftover on the grouping comparison leftover-map
diff --git a/frontend/package.json b/frontend/package.json
index 4ac282897..64af26a98 100644
--- a/frontend/package.json
+++ b/frontend/package.json
@@ -1,7 +1,7 @@
 {
   "name": "frontend",
   "private": true,
-  "version": "2.72.0",
+  "version": "2.73.0",
   "type": "module",
   "scripts": {
     "dev": "vite",
diff --git a/frontend/src/App.test.tsx b/frontend/src/App.test.tsx
index f7f212f1f..7e950b3f4 100644
--- a/frontend/src/App.test.tsx
+++ b/frontend/src/App.test.tsx
@@ -4594,10 +4594,15 @@ describe("App, authenticated", () => {
       )[1],
     ).toHaveTextContent("R +0.40");
     expect(
-      within(screen.getByLabelText("Grouping comparison")).queryByLabelText(
-        /leftover observed/,
+      within(screen.getByLabelText("Grouping comparison")).getByLabelText(
+        "leftover map comparison graphic leftover observed Y 2.40",
       ),
     ).toHaveTextContent("Y 2.40");
+    expect(
+      within(screen.getByLabelText("Grouping comparison")).queryByLabelText(
+        "leftover observed Y 2.40",
+      ),
+    ).not.toBeInTheDocument();
     expect(
       within(screen.getByLabelText("Grouping comparison")).getByLabelText(
         "Leftover map comparison observed",
diff --git a/frontend/src/components/LeftoverMapPlot.test.tsx b/frontend/src/components/LeftoverMapPlot.test.tsx
index 23902ab2b..557fec173 100644
--- a/frontend/src/components/LeftoverMapPlot.test.tsx
+++ b/frontend/src/components/LeftoverMapPlot.test.tsx
@@ -2024,4 +2024,173 @@ describe("LeftoverMapPlot", () => {
     );
     expect(screen.getByText("leftover map comparison axis 1 (0%)")).toBeInTheDocument();
   });
+
+  it("names leftover observed on the comparison graphic with a distinct accessible name", () => {
+    render(
+      <LeftoverMapPlot
+        pairs={PAIRS}
+        leftoverMapAxes={[
+          { axis_index: 1, leftover_singular_value: 1.84, leftover_share: 0.82 },
+          { axis_index: 2, leftover_singular_value: 0.86, leftover_share: 0.18 },
+        ]}
+        leftoverMapCoverage={{
+          map_post_count: 2,
+          scored_post_count: 3,
+          map_item_count: 2,
+          scored_item_count: 2,
+          incomplete_post_count: 1,
+          incomplete_item_count: 0,
+        }}
+        criterionLabel={criterionLabel}
+        onSelectPost={vi.fn()}
+        variant="comparison"
+      />,
+    );
+    expect(
+      screen.getByLabelText("leftover map comparison graphic leftover observed Y 2.40"),
+    ).toHaveTextContent("Y 2.40");
+    expect(
+      screen.getByLabelText("leftover map comparison graphic leftover observed Y 0.90"),
+    ).toHaveTextContent("Y 0.90");
+    expect(screen.queryByLabelText("leftover observed Y 2.40")).not.toBeInTheDocument();
+    expect(screen.queryByLabelText("leftover observed Y 0.90")).not.toBeInTheDocument();
+    expect(screen.queryByLabelText("Leftover map comparison observed")).not.toBeInTheDocument();
+    expect(
+      screen.getByLabelText("leftover map comparison graphic leftover residual R +0.40"),
+    ).toHaveTextContent("R +0.40");
+    expect(
+      screen.getByLabelText("leftover map comparison graphic unexplained leftover U +0.05"),
+    ).toHaveTextContent("U +0.05");
+    expect(
+      screen.getByLabelText("leftover map comparison graphic cross share 2R̂U/R² 0.12"),
+    ).toHaveTextContent("2R̂U/R² 0.12");
+    expect(
+      screen.getByLabelText("leftover map comparison graphic unexplained leftover share U²/R² 0.02"),
+    ).toHaveTextContent("U²/R² 0.02");
+    expect(
+      screen.getByLabelText("leftover map comparison graphic explained leftover share R̂²/R² 0.76"),
+    ).toHaveTextContent("R̂²/R² 0.76");
+    expect(
+      screen.getByLabelText("leftover map comparison graphic reconstruction R̂ +0.25"),
+    ).toHaveTextContent("R̂ +0.25");
+    expect(screen.getByText("leftover map comparison axis 1 (82%)")).toBeInTheDocument();
+  });
+
+  it("omits leftover-map comparison graphic leftover observed when Y is missing or not usable", () => {
+    render(
+      <LeftoverMapPlot
+        pairs={[
+          { ...PAIRS[0], observed_response: Number.NaN },
+          { ...PAIRS[1], observed_response: Number.POSITIVE_INFINITY },
+        ]}
+        leftoverMapAxes={[
+          { axis_index: 1, leftover_singular_value: 1.84, leftover_share: 0.82 },
+          { axis_index: 2, leftover_singular_value: 0.86, leftover_share: 0.18 },
+        ]}
+        leftoverMapCoverage={{
+          map_post_count: 2,
+          scored_post_count: 3,
+          map_item_count: 2,
+          scored_item_count: 2,
+          incomplete_post_count: 1,
+          incomplete_item_count: 0,
+        }}
+        criterionLabel={criterionLabel}
+        onSelectPost={vi.fn()}
+        variant="comparison"
+      />,
+    );
+    expect(screen.queryByLabelText(/leftover map comparison graphic leftover observed Y/)).not.toBeInTheDocument();
+    expect(screen.queryByLabelText(/^leftover observed Y/)).not.toBeInTheDocument();
+    expect(
+      screen.getByLabelText("leftover map comparison graphic leftover residual R +0.40"),
+    ).toHaveTextContent("R +0.40");
+    expect(
+      screen.getByLabelText("leftover map comparison graphic unexplained leftover U +0.05"),
+    ).toHaveTextContent("U +0.05");
+    expect(
+      screen.getByLabelText("leftover map comparison graphic cross share 2R̂U/R² 0.12"),
+    ).toHaveTextContent("2R̂U/R² 0.12");
+    expect(
+      screen.getByLabelText("leftover map comparison graphic unexplained leftover share U²/R² 0.02"),
+    ).toHaveTextContent("U²/R² 0.02");
+    expect(
+      screen.getByLabelText("leftover map comparison graphic explained leftover share R̂²/R² 0.76"),
+    ).toHaveTextContent("R̂²/R² 0.76");
+    expect(
+      screen.getByLabelText("leftover map comparison graphic reconstruction R̂ +0.25"),
+    ).toBeInTheDocument();
+    expect(screen.getByLabelText("leftover-map distance d 0.12")).toBeInTheDocument();
+    expect(screen.getByLabelText("leftover-map distance d 1.84")).toBeInTheDocument();
+    expect(screen.getByLabelText("Leftover map comparison graphic coverage")).toHaveTextContent(
+      "Leftover map used 2 of 3 scored posts (complete-case)",
+    );
+    expect(screen.getByText("leftover map comparison axis 1 (82%)")).toBeInTheDocument();
+  });
+
+  it("names rank-0 origin leftover observed on the comparison graphic when that persisted value is finite", () => {
+    render(
+      <LeftoverMapPlot
+        pairs={[
+          {
+            ...PAIRS[0],
+            leftover_map_person_axis_1: 0,
+            leftover_map_person_axis_2: 0,
+            leftover_map_item_axis_1: 0,
+            leftover_map_item_axis_2: 0,
+            leftover_map_rank: 0,
+            leftover_distance: 0,
+            leftover_residual: 0,
+            leftover_map_reconstruction: 0,
+            leftover_map_explained_share: 0,
+            leftover_map_unexplained_share: 0,
+            leftover_map_cross_share: 0,
+            leftover_map_unexplained: 0,
+            observed_response: 0,
+          },
+        ]}
+        leftoverMapAxes={[
+          { axis_index: 1, leftover_singular_value: 0, leftover_share: 0 },
+          { axis_index: 2, leftover_singular_value: 0, leftover_share: 0 },
+        ]}
+        leftoverMapCoverage={{
+          map_post_count: 0,
+          scored_post_count: 3,
+          map_item_count: 0,
+          scored_item_count: 2,
+          incomplete_post_count: 3,
+          incomplete_item_count: 2,
+        }}
+        criterionLabel={criterionLabel}
+        onSelectPost={vi.fn()}
+        variant="comparison"
+      />,
+    );
+    expect(
+      screen.getByLabelText("leftover map comparison graphic leftover observed Y 0.00"),
+    ).toHaveTextContent("Y 0.00");
+    expect(screen.queryByLabelText("leftover observed Y 0.00")).not.toBeInTheDocument();
+    expect(
+      screen.getByLabelText("leftover map comparison graphic leftover residual R 0.00"),
+    ).toHaveTextContent("R 0.00");
+    expect(
+      screen.getByLabelText("leftover map comparison graphic unexplained leftover U 0.00"),
+    ).toHaveTextContent("U 0.00");
+    expect(
+      screen.getByLabelText("leftover map comparison graphic cross share 2R̂U/R² 0.00"),
+    ).toHaveTextContent("2R̂U/R² 0.00");
+    expect(
+      screen.getByLabelText("leftover map comparison graphic unexplained leftover share U²/R² 0.00"),
+    ).toHaveTextContent("U²/R² 0.00");
+    expect(
+      screen.getByLabelText("leftover map comparison graphic explained leftover share R̂²/R² 0.00"),
+    ).toHaveTextContent("R̂²/R² 0.00");
+    expect(
+      screen.getByLabelText("leftover map comparison graphic reconstruction R̂ 0.00"),
+    ).toHaveTextContent("R̂ 0.00");
+    expect(screen.getByLabelText("Leftover map comparison graphic coverage")).toHaveTextContent(
+      "Leftover map used 0 of 3 scored posts (complete-case)",
+    );
+    expect(screen.getByText("leftover map comparison axis 1 (0%)")).toBeInTheDocument();
+  });
 });
diff --git a/frontend/src/components/LeftoverMapPlot.tsx b/frontend/src/components/LeftoverMapPlot.tsx
index d6f26adb8..5e52e7f49 100644
--- a/frontend/src/components/LeftoverMapPlot.tsx
+++ b/frontend/src/components/LeftoverMapPlot.tsx
@@ -39,6 +39,7 @@ import {
   LEFTOVER_MAP_COMPARE_PLOT_SEGMENT_CROSS_SHARE,
   LEFTOVER_MAP_COMPARE_PLOT_SEGMENT_UNEXPLAINED,
   LEFTOVER_MAP_COMPARE_PLOT_SEGMENT_RESIDUAL,
+  LEFTOVER_MAP_COMPARE_PLOT_SEGMENT_OBSERVED,
   LEFTOVER_MAP_PLOT_CAPTION,
   LEFTOVER_MAP_PLOT_POST_ACTION,
   LEFTOVER_MAP_PLOT_SEGMENT_CROSS_SHARE,
@@ -161,6 +162,9 @@ function leftoverMapPlotAxisText(
  * labels. ADR 0315 captions leftover residual on that
  * comparison graphic from already-named leftover residual
  * with distinct leftover map comparison graphic leftover residual
+ * labels. ADR 0316 captions leftover observed on that
+ * comparison graphic from already-named leftover observed
+ * with distinct leftover map comparison graphic leftover observed
  * labels.
  * Never invent a leftover score.
  */
@@ -426,9 +430,12 @@ export function LeftoverMapPlot({
                   x={segment.observedX}
                   y={segment.observedY}
                   textAnchor="middle"
-                  aria-label={tf(LEFTOVER_MAP_PLOT_SEGMENT_OBSERVED, {
-                    label: segment.observedLabel,
-                  })}
+                  aria-label={tf(
+                    variant === "comparison"
+                      ? LEFTOVER_MAP_COMPARE_PLOT_SEGMENT_OBSERVED
+                      : LEFTOVER_MAP_PLOT_SEGMENT_OBSERVED,
+                    { label: segment.observedLabel },
+                  )}
                 >
                   {segment.observedLabel}
                 </text>
diff --git a/frontend/src/components/LeftoverPairList.tsx b/frontend/src/components/LeftoverPairList.tsx
index f0e60a47c..cdc5e10f2 100644
--- a/frontend/src/components/LeftoverPairList.tsx
+++ b/frontend/src/components/LeftoverPairList.tsx
@@ -124,7 +124,8 @@ export type LeftoverPairListProps = {
  * pair list. ADR 0314 captions leftover-map unexplained leftover on that
  * grouping comparison leftover-map graphic, not this pair list. ADR 0315
  * captions leftover residual on that grouping comparison leftover-map graphic,
- * not this pair list. Every badge still
+ * not this pair list. ADR 0316 captions leftover observed on that
+ * grouping comparison leftover-map graphic, not this pair list. Every badge still
  * renders together before opening the named post.
  */
 export function LeftoverPairList({
diff --git a/frontend/src/i18n.test.ts b/frontend/src/i18n.test.ts
index 09d6d6115..8f7b69eb4 100644
--- a/frontend/src/i18n.test.ts
+++ b/frontend/src/i18n.test.ts
@@ -97,6 +97,7 @@ describe("i18n", () => {
     "Leftover map comparison unexplained leftover",
     "leftover map comparison graphic leftover residual {label}",
     "Leftover map comparison residual",
+    "leftover map comparison graphic leftover observed {label}",
     "Leftover map comparison observed",
     "Leftover map comparison expected",
     "Leftover map comparison rank",
@@ -597,6 +598,23 @@ describe("i18n", () => {
     },
   );
 
+  it.each([
+    ["ko", "잔여 지도 비교 그림 관측 Y 2.40"],
+    ["zh", "残差地图比较图形观测 Y 2.40"],
+    ["ja", "残差マップの比較図観測 Y 2.40"],
+    ["vi", "quan sát đồ họa so sánh bản đồ phần dư Y 2.40"],
+  ] as const)(
+    "formats leftover map comparison graphic leftover observed in %s",
+    (locale, expected) => {
+      setLocale(locale);
+      expect(
+        tf("leftover map comparison graphic leftover observed {label}", {
+          label: "Y 2.40",
+        }),
+      ).toBe(expected);
+    },
+  );
+
   it.each([
     ["ko", "잔여 지도 비교 설명 잔여 점유율"],
     ["zh", "残差地图比较已解释残差份额"],
diff --git a/frontend/src/i18n.ts b/frontend/src/i18n.ts
index 7452be173..0c32ac23c 100644
--- a/frontend/src/i18n.ts
+++ b/frontend/src/i18n.ts
@@ -289,6 +289,7 @@ const TRANSLATIONS: Partial<Record<Locale, Record<string, string>>> = {
     "Leftover map comparison unexplained leftover": "잔여 지도 비교 미설명 잔여",
     "leftover map comparison graphic leftover residual {label}": "잔여 지도 비교 그림 잔여 {label}",
     "Leftover map comparison residual": "잔여 지도 비교 잔여",
+    "leftover map comparison graphic leftover observed {label}": "잔여 지도 비교 그림 관측 {label}",
     "Leftover map comparison observed": "잔여 지도 비교 관측",
     "Leftover map comparison expected": "잔여 지도 비교 기대",
     "Leftover map comparison rank": "잔여 지도 비교 순위",
@@ -927,6 +928,7 @@ const TRANSLATIONS: Partial<Record<Locale, Record<string, string>>> = {
     "Leftover map comparison unexplained leftover": "残差地图比较未解释残差",
     "leftover map comparison graphic leftover residual {label}": "残差地图比较图形残差 {label}",
     "Leftover map comparison residual": "残差地图比较残差",
+    "leftover map comparison graphic leftover observed {label}": "残差地图比较图形观测 {label}",
     "Leftover map comparison observed": "残差地图比较观测",
     "Leftover map comparison expected": "残差地图比较期望",
     "Leftover map comparison rank": "残差地图比较秩",
@@ -1586,6 +1588,7 @@ const TRANSLATIONS: Partial<Record<Locale, Record<string, string>>> = {
     "Leftover map comparison unexplained leftover": "残差マップの比較未説明残差",
     "leftover map comparison graphic leftover residual {label}": "残差マップの比較図残差 {label}",
     "Leftover map comparison residual": "残差マップの比較残差",
+    "leftover map comparison graphic leftover observed {label}": "残差マップの比較図観測 {label}",
     "Leftover map comparison observed": "残差マップの比較観測",
     "Leftover map comparison expected": "残差マップの比較期待",
     "Leftover map comparison rank": "残差マップの比較階数",
@@ -2224,6 +2227,7 @@ const TRANSLATIONS: Partial<Record<Locale, Record<string, string>>> = {
     "Leftover map comparison unexplained leftover": "Phần dư chưa giải thích so sánh",
     "leftover map comparison graphic leftover residual {label}": "phần dư đồ họa so sánh bản đồ phần dư {label}",
     "Leftover map comparison residual": "Phần dư so sánh bản đồ phần dư",
+    "leftover map comparison graphic leftover observed {label}": "quan sát đồ họa so sánh bản đồ phần dư {label}",
     "Leftover map comparison observed": "Quan sát so sánh bản đồ phần dư",
     "Leftover map comparison expected": "Kỳ vọng so sánh bản đồ phần dư",
     "Leftover map comparison rank": "Hạng so sánh bản đồ phần dư",
diff --git a/frontend/src/leftoverMapPlotLayout.test.ts b/frontend/src/leftoverMapPlotLayout.test.ts
index 44a55a220..a86e909a9 100644
--- a/frontend/src/leftoverMapPlotLayout.test.ts
+++ b/frontend/src/leftoverMapPlotLayout.test.ts
@@ -13,6 +13,7 @@ import {
   LEFTOVER_MAP_COMPARE_PLOT_SEGMENT_CROSS_SHARE,
   LEFTOVER_MAP_COMPARE_PLOT_SEGMENT_UNEXPLAINED,
   LEFTOVER_MAP_COMPARE_PLOT_SEGMENT_RESIDUAL,
+  LEFTOVER_MAP_COMPARE_PLOT_SEGMENT_OBSERVED,
   LEFTOVER_MAP_COMPARE_PLOT_SVG,
   PLOT_HEIGHT,
   PLOT_PADDING,
@@ -1288,4 +1289,19 @@ describe("leftover map comparison graphic labels", () => {
       LEFTOVER_MAP_COMPARE_PLOT_SEGMENT_UNEXPLAINED,
     );
   });
+
+  it("stays distinct from leftover observed copy", () => {
+    expect(LEFTOVER_MAP_COMPARE_PLOT_SEGMENT_OBSERVED).toBe(
+      "leftover map comparison graphic leftover observed {label}",
+    );
+    expect(LEFTOVER_MAP_COMPARE_PLOT_SEGMENT_OBSERVED).not.toBe(
+      "leftover observed {label}",
+    );
+    expect(LEFTOVER_MAP_COMPARE_PLOT_SEGMENT_OBSERVED).not.toBe(
+      "Leftover map comparison observed",
+    );
+    expect(LEFTOVER_MAP_COMPARE_PLOT_SEGMENT_OBSERVED).not.toBe(
+      LEFTOVER_MAP_COMPARE_PLOT_SEGMENT_RESIDUAL,
+    );
+  });
 });
diff --git a/frontend/src/leftoverMapPlotLayout.ts b/frontend/src/leftoverMapPlotLayout.ts
index 77728d5ca..ca743c532 100644
--- a/frontend/src/leftoverMapPlotLayout.ts
+++ b/frontend/src/leftoverMapPlotLayout.ts
@@ -41,9 +41,10 @@
  *  reconstruction on that graphic (ADR 0310), grouping comparison leftover-map
  *  explained leftover share on that graphic (ADR 0311), grouping comparison leftover-map
  *  unexplained leftover share on that graphic (ADR 0312), grouping comparison leftover-map
- *  cross share on that graphic (ADR 0313), and grouping comparison leftover-map
- *  unexplained leftover on that graphic (ADR 0314), and grouping comparison leftover
- *  residual on that graphic (ADR 0315) caption the pair list or the grouping comparison
+ *  cross share on that graphic (ADR 0313), grouping comparison leftover-map
+ *  unexplained leftover on that graphic (ADR 0314), grouping comparison leftover
+ *  residual on that graphic (ADR 0315), and grouping comparison leftover
+ *  observed on that graphic (ADR 0316) caption the pair list or the grouping comparison
  *  strip. ADR 0304 reuses this graphic layout on the grouping comparison
  *  strip. ADR 0305 captions leftover-map axis share on that comparison
  *  graphic from already-named leftover-map axes. ADR 0306 captions leftover-map
@@ -63,6 +64,8 @@
  *  comparison graphic from already-named leftover-map unexplained leftover.
  *  ADR 0315 captions leftover residual on that comparison graphic from
  *  already-named leftover residual.
+ *  ADR 0316 captions leftover observed on that comparison graphic from already-named
+ *  leftover observed.
  */
 
 import { formatLeftoverMapCoordinatePair } from "./leftoverMapCoordinates";
@@ -131,6 +134,8 @@ export { LEFTOVER_MAP_COMPARE_PLOT_SEGMENT_RESIDUAL } from "./leftoverResidual";
 export const LEFTOVER_MAP_PLOT_SEGMENT_OBSERVED =
   "leftover observed {label}";
 
+export { LEFTOVER_MAP_COMPARE_PLOT_SEGMENT_OBSERVED } from "./leftoverObservedExpected";
+
 export const LEFTOVER_MAP_PLOT_SEGMENT_EXPECTED =
   "leftover expected {label}";
 
diff --git a/frontend/src/leftoverObservedExpected.test.ts b/frontend/src/leftoverObservedExpected.test.ts
index 561a599b4..c38c454c8 100644
--- a/frontend/src/leftoverObservedExpected.test.ts
+++ b/frontend/src/leftoverObservedExpected.test.ts
@@ -5,6 +5,7 @@ import {
   formatLeftoverObservedExpected,
   LEFTOVER_MAP_COMPARE_OBSERVED_LABEL,
   LEFTOVER_MAP_COMPARE_EXPECTED_LABEL,
+  LEFTOVER_MAP_COMPARE_PLOT_SEGMENT_OBSERVED,
 } from "./leftoverObservedExpected";
 
 describe("formatLeftoverObservedExpected", () => {
@@ -41,6 +42,19 @@ describe("formatLeftoverMapObserved", () => {
     expect(LEFTOVER_MAP_COMPARE_OBSERVED_LABEL).toBe("Leftover map comparison observed");
     expect(LEFTOVER_MAP_COMPARE_OBSERVED_LABEL).not.toBe("leftover observed {label}");
   });
+
+  it("keeps the grouping comparison graphic leftover observed label distinct from the graphic and strip labels", () => {
+    expect(LEFTOVER_MAP_COMPARE_PLOT_SEGMENT_OBSERVED).toBe(
+      "leftover map comparison graphic leftover observed {label}",
+    );
+    expect(LEFTOVER_MAP_COMPARE_PLOT_SEGMENT_OBSERVED).not.toBe("leftover observed {label}");
+    expect(LEFTOVER_MAP_COMPARE_PLOT_SEGMENT_OBSERVED).not.toBe(
+      LEFTOVER_MAP_COMPARE_OBSERVED_LABEL,
+    );
+    expect(LEFTOVER_MAP_COMPARE_PLOT_SEGMENT_OBSERVED).not.toBe(
+      "leftover map comparison graphic leftover residual {label}",
+    );
+  });
 });
 
 describe("formatLeftoverMapExpected", () => {
diff --git a/frontend/src/leftoverObservedExpected.ts b/frontend/src/leftoverObservedExpected.ts
index a647dae15..bffbab8c3 100644
--- a/frontend/src/leftoverObservedExpected.ts
+++ b/frontend/src/leftoverObservedExpected.ts
@@ -3,6 +3,9 @@
 export const LEFTOVER_MAP_COMPARE_OBSERVED_LABEL =
   "Leftover map comparison observed";
 
+export const LEFTOVER_MAP_COMPARE_PLOT_SEGMENT_OBSERVED =
+  "leftover map comparison graphic leftover observed {label}";
+
 export const LEFTOVER_MAP_COMPARE_EXPECTED_LABEL =
   "Leftover map comparison expected";
 
diff --git a/pyproject.toml b/pyproject.toml
index f0016537b..e18874584 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -1,6 +1,6 @@
 [project]
 name = "lineageweave"
-version = "2.72.0"
+version = "2.73.0"
 description = "Reconstructs git-branch-style lineage DAGs from scattered short records using multi-channel score fusion and LLM adjudication."
 readme = "README.md"
 license = { text = "MIT" }
diff --git a/tests/test_adr_0316_governance.py b/tests/test_adr_0316_governance.py
new file mode 100644
index 000000000..069f1297e
--- /dev/null
+++ b/tests/test_adr_0316_governance.py
@@ -0,0 +1,13 @@
+"""Governance regression for the draft ADR 0316 decision state."""
+
+from pathlib import Path
+
+
+ADR_PATH = Path(__file__).parents[1] / "docs/adr/0316-leftover-map-compare-plot-observed.md"
+
+
+def test_draft_adr_0316_remains_proposed() -> None:
+    """Keep the unmerged decision proposed until independent acceptance exists."""
+    text = ADR_PATH.read_text(encoding="utf-8")
+    assert "**Decision status:** Proposed" in text
+    assert "**Decision status:** Accepted" not in text
diff --git a/uv.lock b/uv.lock
index e04d99617..8226b9653 100644
--- a/uv.lock
+++ b/uv.lock
@@ -685,7 +685,7 @@ wheels = [
 
 [[package]]
 name = "lineageweave"
-version = "2.72.0"
+version = "2.73.0"
 source = { editable = "." }
 dependencies = [
     { name = "certifi" },