Document that Northern Ireland business rates count regional and district rates

changelog.d/ni-business-rates-regional-district.changed.md

@@ -0,0 +1 @@
+- Documented that the Northern Ireland business rates statistic counts the regional and district rates, while the OBR line that projects it covers the regional rate only.

policyengine_uk/data/fiscal_partition.yaml

@@ -343,9 +343,13 @@ tax_heads:
       projected with OBR receipts (gov.hmrc.business_rates.statistics). In
       2026-27 the England, Scotland and Wales series total £37.26bn against
       £37.41bn on the OBR's Business rates line (receipts Table 3.8).
-      Northern Ireland's £0.78bn (LPS non-domestic rates paid) compares with
-      £0.40bn on the OBR's "Northern Ireland business rates" line, which the
-      OBR records under other taxes (Table 3.2). Measured 2026-10-11.
+      Northern Ireland's £0.78bn (LPS non-domestic rates paid, regional and
+      district rates together) compares with £0.40bn on the OBR's "Northern
+      Ireland business rates" line, which the OBR records under other taxes
+      (Table 3.2) and which covers the regional rate only. ONS records NI
+      regional non-domestic rates (central government, £327m in 2024-25) and
+      district non-domestic rates (local government, £378m) separately.
+      Measured 2026-10-11.
   - id: sdlt_household
     label: Stamp duty land tax on the household's own purchases
     variable: expected_sdlt

policyengine_uk/parameters/gov/economic_assumptions/yoy_growth.yaml

@@ -739,7 +739,7 @@ obr:
           - title: OBR EFO March 2025 (detailed forecast tables, receipts, Table 3.9; 2023-24 outturn)
             href: https://obr.uk/efo/economic-and-fiscal-outlook-march-2025/
     northern_ireland:
-      description: Growth in Northern Ireland business rates receipts (the OBR "Northern Ireland business rates" line in other taxes).
+      description: Growth in Northern Ireland business rates receipts (the OBR "Northern Ireland business rates" line in other taxes, which covers the regional rate; also applied to district rates, which councils set a year at a time).
       values:
         # Outturn (2024-25 over 2023-24), Table 3.2 "Northern Ireland business rates"
         2024-01-01: 0.032513

policyengine_uk/parameters/gov/hmrc/business_rates/statistics.yaml

@@ -10,7 +10,9 @@ metadata:
 #   span several authorities), whose rates are paid to the Secretary of State
 #   or the Welsh Government instead.
 # - Scotland: the contributable amount councils pay into the national pool.
-# - Northern Ireland: non-domestic rates paid to Land & Property Services.
+# - Northern Ireland: non-domestic rates paid to Land & Property Services,
+#   which levies the regional rate and each council's district rate as one
+#   bill.
 # business_rates allocates all of it by shareholding, a modelling convention
 # that applies to every ratepayer on the lists, including, on the Welsh
 # central list in 2024-25, Network Rail (£10.5m) and Dwr Cymru (£17.0m) of
@@ -26,7 +28,8 @@ metadata:
 # After its latest outturn year each series is projected by uprating with the
 # OBR's receipts forecast: England, Scotland and Wales with the OBR's
 # "Business rates" line, Northern Ireland with its "Northern Ireland business
-# rates" line (gov.economic_assumptions.yoy_growth.obr.business_rates). The
+# rates" line (gov.economic_assumptions.yoy_growth.obr.business_rates), which
+# covers the regional rate only (see NORTHERN_IRELAND below). The
 # economic-assumption indices run to 2039, so every series is flat in cash
 # terms from 2039-40.
 revenue:
@@ -128,11 +131,27 @@ revenue:
       reference:
         - title: StatsWales, Non-domestic rates central list, "Total Rates Received", Wales (2019-20 to 2024-25)
           href: https://stats.gov.wales/en-GB/ddada8b1-60ac-4a9a-8a8e-4e04df23d2f8/start
+  # A Northern Ireland rate bill is the regional rate, made by the Department
+  # of Finance, plus the council's district rate, levied "as if they were
+  # items of a single rate" (Rates (Northern Ireland) Order 1977, art 9(1)).
+  # This series counts both. The OBR's "Northern Ireland business rates" line
+  # that projects it covers the regional rate only, so it is about half this
+  # level: £382m against £741m in 2024-25.
+  # - ONS records NI regional non-domestic rates (central government, £327m
+  #   in 2024-25) and district non-domestic rates (local government, £378m)
+  #   separately (Country and regional public sector finances, financial year
+  #   ending 2025).
+  # - Splitting each council's 2024-25 payments by its regional (29.02p) and
+  #   district (25.57p to 38.22p) poundages gives a regional part of £364m.
+  # - Councils set district rates a year at a time and no official forecast
+  #   covers later years, so the district part is assumed to grow with the
+  #   OBR's regional line.
   NORTHERN_IRELAND:
     description: >-
       Non-domestic rates paid against ratepayer accounts in the rating year,
-      Northern Ireland. The series starts in 2020-21 (a rates-holiday year),
-      and earlier years take that value.
+      Northern Ireland, regional and district rates together. The series
+      starts in 2020-21 (a rates-holiday year), and earlier years take that
+      value.
     values:
       2020-01-01: 380_876_615
       2021-01-01: 446_688_825