juaristi22 · Nov 6, 2026 · Nov 6, 2026 · Nov 6, 2026
diff --git a/changelog.d/nrs-data-zone-council-tax-bands-419.added.md b/changelog.d/nrs-data-zone-council-tax-bands-419.added.md
@@ -0,0 +1 @@
+Add the council tax band columns of NRS's dwelling estimates by 2022 data zone, which chronicle#419 asks for (PolicyEngine/microcosm#931): dwellings in bands A to H in each of Scotland's 7,392 data zones, December 2024 and December 2025, as `nrs.dwellings_band_a` to `nrs.dwellings_band_h` beside `nrs.dwellings_total` in `nrs-dwellings-data-zone-2025`. A test checks that the eight bands add up to the zone's total in every zone of both sheets.
diff --git a/packages/nrs/dwellings_data_zone_2025/source_package.yaml b/packages/nrs/dwellings_data_zone_2025/source_package.yaml
@@ -81358,6 +81358,110 @@ record_sets:
     expected_cell_type: number
     expected_column_header_row: 5
     expected_column_header: Total number of dwellings
+  - measure_id: nrs_dwellings_band_a
+    label: Dwellings, Council Tax band A
+    ordinal: 1
+    column: G
+    source_column_id: council_tax_band_a
+    concept: nrs.dwellings_band_a
+    unit: count
+    aggregation: sum
+    expected_cell_type: number
+    expected_column_header_row: 5
+    expected_column_header: 'Council Tax band:
+
+      A'
+  - measure_id: nrs_dwellings_band_b
+    label: Dwellings, Council Tax band B
+    ordinal: 2
+    column: H
+    source_column_id: council_tax_band_b
+    concept: nrs.dwellings_band_b
+    unit: count
+    aggregation: sum
+    expected_cell_type: number
+    expected_column_header_row: 5
+    expected_column_header: 'Council Tax band:
+
+      B'
+  - measure_id: nrs_dwellings_band_c
+    label: Dwellings, Council Tax band C
+    ordinal: 3
+    column: I
+    source_column_id: council_tax_band_c
+    concept: nrs.dwellings_band_c
+    unit: count
+    aggregation: sum
+    expected_cell_type: number
+    expected_column_header_row: 5
+    expected_column_header: 'Council Tax band:
+
+      C'
+  - measure_id: nrs_dwellings_band_d
+    label: Dwellings, Council Tax band D
+    ordinal: 4
+    column: J
+    source_column_id: council_tax_band_d
+    concept: nrs.dwellings_band_d
+    unit: count
+    aggregation: sum
+    expected_cell_type: number
+    expected_column_header_row: 5
+    expected_column_header: 'Council Tax band:
+
+      D'
+  - measure_id: nrs_dwellings_band_e
+    label: Dwellings, Council Tax band E
+    ordinal: 5
+    column: K
+    source_column_id: council_tax_band_e
+    concept: nrs.dwellings_band_e
+    unit: count
+    aggregation: sum
+    expected_cell_type: number
+    expected_column_header_row: 5
+    expected_column_header: 'Council Tax band:
+
+      E'
+  - measure_id: nrs_dwellings_band_f
+    label: Dwellings, Council Tax band F
+    ordinal: 6
+    column: L
+    source_column_id: council_tax_band_f
+    concept: nrs.dwellings_band_f
+    unit: count
+    aggregation: sum
+    expected_cell_type: number
+    expected_column_header_row: 5
+    expected_column_header: 'Council Tax band:
+
+      F'
+  - measure_id: nrs_dwellings_band_g
+    label: Dwellings, Council Tax band G
+    ordinal: 7
+    column: M
+    source_column_id: council_tax_band_g
+    concept: nrs.dwellings_band_g
+    unit: count
+    aggregation: sum
+    expected_cell_type: number
+    expected_column_header_row: 5
+    expected_column_header: 'Council Tax band:
+
+      G'
+  - measure_id: nrs_dwellings_band_h
+    label: Dwellings, Council Tax band H
+    ordinal: 8
+    column: N
+    source_column_id: council_tax_band_h
+    concept: nrs.dwellings_band_h
+    unit: count
+    aggregation: sum
+    expected_cell_type: number
+    expected_column_header_row: 5
+    expected_column_header: 'Council Tax band:
+
+      H'
   period_coverage:
     start_date: '2024-12-31'
     end_date: '2024-12-31'
@@ -162704,6 +162808,110 @@ record_sets:
     expected_cell_type: number
     expected_column_header_row: 5
     expected_column_header: Total number of dwellings
+  - measure_id: nrs_dwellings_band_a
+    label: Dwellings, Council Tax band A
+    ordinal: 1
+    column: G
+    source_column_id: council_tax_band_a
+    concept: nrs.dwellings_band_a
+    unit: count
+    aggregation: sum
+    expected_cell_type: number
+    expected_column_header_row: 5
+    expected_column_header: 'Council Tax band:
+
+      A'
+  - measure_id: nrs_dwellings_band_b
+    label: Dwellings, Council Tax band B
+    ordinal: 2
+    column: H
+    source_column_id: council_tax_band_b
+    concept: nrs.dwellings_band_b
+    unit: count
+    aggregation: sum
+    expected_cell_type: number
+    expected_column_header_row: 5
+    expected_column_header: 'Council Tax band:
+
+      B'
+  - measure_id: nrs_dwellings_band_c
+    label: Dwellings, Council Tax band C
+    ordinal: 3
+    column: I
+    source_column_id: council_tax_band_c
+    concept: nrs.dwellings_band_c
+    unit: count
+    aggregation: sum
+    expected_cell_type: number
+    expected_column_header_row: 5
+    expected_column_header: 'Council Tax band:
+
+      C'
+  - measure_id: nrs_dwellings_band_d
+    label: Dwellings, Council Tax band D
+    ordinal: 4
+    column: J
+    source_column_id: council_tax_band_d
+    concept: nrs.dwellings_band_d
+    unit: count
+    aggregation: sum
+    expected_cell_type: number
+    expected_column_header_row: 5
+    expected_column_header: 'Council Tax band:
+
+      D'
+  - measure_id: nrs_dwellings_band_e
+    label: Dwellings, Council Tax band E
+    ordinal: 5
+    column: K
+    source_column_id: council_tax_band_e
+    concept: nrs.dwellings_band_e
+    unit: count
+    aggregation: sum
+    expected_cell_type: number
+    expected_column_header_row: 5
+    expected_column_header: 'Council Tax band:
+
+      E'
+  - measure_id: nrs_dwellings_band_f
+    label: Dwellings, Council Tax band F
+    ordinal: 6
+    column: L
+    source_column_id: council_tax_band_f
+    concept: nrs.dwellings_band_f
+    unit: count
+    aggregation: sum
+    expected_cell_type: number
+    expected_column_header_row: 5
+    expected_column_header: 'Council Tax band:
+
+      F'
+  - measure_id: nrs_dwellings_band_g
+    label: Dwellings, Council Tax band G
+    ordinal: 7
+    column: M
+    source_column_id: council_tax_band_g
+    concept: nrs.dwellings_band_g
+    unit: count
+    aggregation: sum
+    expected_cell_type: number
+    expected_column_header_row: 5
+    expected_column_header: 'Council Tax band:
+
+      G'
+  - measure_id: nrs_dwellings_band_h
+    label: Dwellings, Council Tax band H
+    ordinal: 8
+    column: N
+    source_column_id: council_tax_band_h
+    concept: nrs.dwellings_band_h
+    unit: count
+    aggregation: sum
+    expected_cell_type: number
+    expected_column_header_row: 5
+    expected_column_header: 'Council Tax band:
+
+      H'
   period_coverage:
     start_date: '2025-12-31'
     end_date: '2025-12-31'

diff --git a/packages/uk_local_2025_sources.md b/packages/uk_local_2025_sources.md
@@ -4,7 +4,7 @@ Chronicle preserves the publisher artifacts requested in [issue 313](https://git
 
 | Source family | Packages and coverage | Publisher semantics |
 | --- | --- | --- |
-| Scotland households | `nrs-households-dwellings-2025`, `nrs-households-data-zone-2025`, `nrs-dwellings-data-zone-2025` | Council and country private-household estimates: June 2024/2025. Council dwelling stock: September. Data-zone occupied dwellings: September; dwelling stock: December. The small-area occupied-dwelling table does not assert the adjusted private-household estimate. |
+| Scotland households | `nrs-households-dwellings-2025`, `nrs-households-data-zone-2025`, `nrs-dwellings-data-zone-2025` | Council and country private-household estimates: June 2024/2025. Council dwelling stock: September. Data-zone occupied dwellings: September; dwelling stock: December, in total and by council tax band A–H ([issue 419](https://github.com/PolicyEngine/chronicle/issues/419)). The small-area occupied-dwelling table does not assert the adjusted private-household estimate. |
 | Wales households | `welshgov-household-estimates-mid2024`, `welshgov-household-projections-2022-based` | Revised mid-2022/2023/2024 estimates and principal mid-2025 projection. Publisher decimals retained. The estimate selector excludes private-household population and average household size. |
 | England households | `ons-household-projections-2022-based` | Table 406, all 349 areas, mid-2022 through mid-2047, 2022 boundaries; metropolitan counties remain counties. `source_projection` identifies each publisher projection. |
 | NI housing stock | `lps-housing-stock-lgd-2026` | Eleven districts and NI country, 1 April 2021–2026. Domestic or mixed-rated dwelling stock. Chronicle retains the published snapshots; consumers calculate roll-forward factors. |

diff --git a/tests/test_chronicle_bundle.py b/tests/test_chronicle_bundle.py
@@ -562,7 +562,12 @@ def test_build_bundle_writes_merged_consumer_contract(tmp_path):
         # Survey's chapters 1, 3 and 4 (4,458), HMRC's stamp tax Tables 2e, 3a,
         # 5a, 7, 9a and 9d (1,135), ONS's land by sector (387) and the council
         # rows of the Welsh (308) and Scottish (96) council tax tables.
-        "fact_count": 2062484,
+        # chronicle#419 adds 118,272 dwelling facts: NRS's council tax bands A to
+        # H for each of Scotland's 7,392 2022 data zones, December 2024 and
+        # December 2025. Measured with only nrs-dwellings-data-zone-2025 at
+        # bundle year 2023: no new geography, period or entity key, duplicate
+        # key or warning.
+        "fact_count": 2180756,
         # The same change adds 82,064 geography keys: 46,363 Scottish 2022
         # output areas (UV404), 35,673 LSOA-level keys from the DESNZ LSOA
         # workbooks (Scotland's data zones already exist), the 26 Northern
@@ -686,7 +691,7 @@ def test_build_bundle_writes_merged_consumer_contract(tmp_path):
         if row_count == 1:
             assert row["aggregate_fact_key"].startswith("ledger.aggregate_fact.v2:")
             assert row["semantic_fact_key"].startswith("ledger.semantic_fact.v2:")
-    assert row_count == 2062484
+    assert row_count == 2180756
     assert provenance_classes <= {
         "administrative",
         "census",
@@ -721,7 +726,7 @@ def test_build_bundle_writes_merged_consumer_contract(tmp_path):
         "jct-obbba-revenue-estimates-2025",
         "jct-tax-expenditures-2024",
     ]
-    assert coverage["fact_count"] == 2062484
+    assert coverage["fact_count"] == 2180756
     assert coverage["counts"]["by_source"] == {
         "bea": 446,
         "bfp_economic_outlook": 5,
@@ -759,7 +764,7 @@ def test_build_bundle_writes_merged_consumer_contract(tmp_path):
         "nbb_national_accounts": 1,
         "nisra": 29227,
         "nithc": 8,
-        "nrs": 359094,
+        "nrs": 477366,
         "obr": 4539,
         "ofgem": 3640,
         "onem_rva_unemployment": 1,
@@ -2532,6 +2537,10 @@ def test_build_bundle_writes_merged_consumer_contract(tmp_path):
     }
     for key, count in chronicle_408_period_increments.items():
         expected_period_counts[key] = expected_period_counts.get(key, 0) + count
+    # chronicle#419: NRS's eight council tax bands for each of the 7,392 data
+    # zones, at December 2024 and December 2025.
+    for year in (2024, 2025):
+        expected_period_counts[f"calendar_year:{year}"] += 8 * 7392
     assert coverage["counts"]["by_period"] == expected_period_counts
     # country:NZ: 330 WFF (#209) + 5 national population (#211) + 27 Treasury
     # (#321) + 3,522 IRD I1 (#318) + 510 IRD I2 (#210) + 103 MSD (#319)
@@ -2675,9 +2684,10 @@ def test_build_bundle_writes_merged_consumer_contract(tmp_path):
     # QRC4 5,757, Table 6 1,208, Wales 308 and Scotland 96), households +1,666
     # (the Market Value Survey), returns +1,135 (HMRC's stamp tax), firms +401
     # (the land value estimates) and institutional sectors +387 (ONS's land).
+    # chronicle#419: dwellings +118,272 (NRS's council tax bands by data zone).
     assert coverage["counts"]["by_entity"] == {
         "benefit_unit": 33645,
-        "dwelling": 590264,
+        "dwelling": 708536,
         "family": 1700,
         "firm": 1905,
         "government": 14071,

diff --git a/tests/test_chronicle_uk_local_2025.py b/tests/test_chronicle_uk_local_2025.py
@@ -2,9 +2,10 @@
 
 import hashlib
 import json
-from collections import defaultdict
+from collections import Counter, defaultdict
 from dataclasses import replace
 from datetime import datetime
+from functools import lru_cache
 from pathlib import Path
 
 import pytest
@@ -13,6 +14,20 @@
 from chronicle.consumer_contract import validate_consumer_fact_contract
 from chronicle.source_package import SOURCE_PACKAGE_ALIASES, load_source_package
 
+# NRS dwellings by 2022 data zone: council tax bands A to H in columns G to N.
+DATA_ZONE_BAND_COLUMNS = dict(zip("ABCDEFGH", "GHIJKLMN", strict=True))
+
+
+@lru_cache
+def _data_zone_dwellings():
+    return load_source_package("nrs-dwellings-data-zone-2025")
+
+
+@lru_cache
+def _data_zone_dwelling_cells():
+    # Parsing the workbook takes over a minute; building facts from its cells, 8s.
+    return _data_zone_dwellings().build_source_cells(2025)
+
 
 def test_mid2025_local_authority_population_keeps_all_four_nations():
     """Nomis NM_31_1 must retain NI's eleven districts alongside GB."""
@@ -107,6 +122,49 @@ def test_household_controls_keep_private_households_projections_and_stock_distin
     }
 
 
+def test_scottish_data_zone_council_tax_bands_sum_to_each_zone_total():
+    """chronicle#419: columns G to N (bands A to H) add up to column E."""
+    facts = _data_zone_dwellings().build_facts(2025, cells=_data_zone_dwelling_cells())
+    bands = tuple(f"nrs.dwellings_band_{band}" for band in "abcdefgh")
+    zones = defaultdict(dict)
+    for fact in facts:
+        zones[fact.period.value, fact.geography.id][fact.measure.concept] = fact.value
+    assert len(facts) == 2 * 7_392 * 9
+    assert Counter(period for period, _ in zones) == {2024: 7_392, 2025: 7_392}
+    for key, values in zones.items():
+        assert set(values) == {"nrs.dwellings_total", *bands}, key
+        assert sum(values[band] for band in bands) == values["nrs.dwellings_total"], key
+    # Culter - 01 (S01013482, row 6), bands A to H as published.
+    published = {
+        2024: [21, 153, 45, 55, 100, 44, 85, 13],
+        2025: [21, 153, 45, 55, 99, 45, 85, 13],
+    }
+    for period, counts in published.items():
+        assert [zones[period, "S01013482"][band] for band in bands] == counts
+    assert all(f.source_cell_keys for f in facts)
+    assert validate_consumer_fact_contract(facts).valid
+
+
+@pytest.mark.parametrize("sheet", ["2024", "2025"])
+@pytest.mark.parametrize("band", list(DATA_ZONE_BAND_COLUMNS))
+def test_scottish_data_zone_band_header_guards_reject_drift(sheet, band):
+    """Each band's guard stops the build when its column holds the next band."""
+    address = f"{DATA_ZONE_BAND_COLUMNS[band]}5"
+    next_band = "BCDEFGHA"["ABCDEFGH".index(band)]
+    changed_cells = [
+        replace(cell, raw_value=f"Council Tax band:\n{next_band}")
+        if (cell.sheet_name, cell.address) == (sheet, address)
+        else cell
+        for cell in _data_zone_dwelling_cells()
+    ]
+    measure = f"nrs_dwellings_band_{band.lower()}"
+    with pytest.raises(
+        ValueError,
+        match=rf"\.{sheet}\.\w+\.{measure}\.selector' expected column header",
+    ):
+        _data_zone_dwellings().build_facts(2025, cells=changed_cells)
+
+
 def test_rm120_retains_age_sex_residence_and_2023_lad_boundaries():
     facts = load_source_package(
         "ons-census2021-rm120-pcon24-residence2-sex0"
Original file line number	Diff line number	Diff line change
		@@ -0,0 +1 @@
		Add the council tax band columns of NRS's dwelling estimates by 2022 data zone, which chronicle#419 asks for (PolicyEngine/microcosm#931): dwellings in bands A to H in each of Scotland's 7,392 data zones, December 2024 and December 2025, as `nrs.dwellings_band_a` to `nrs.dwellings_band_h` beside `nrs.dwellings_total` in `nrs-dwellings-data-zone-2025`. A test checks that the eight bands add up to the zone's total in every zone of both sheets.