Default the BRMA from the household's region

changelog.d/2020.fixed.md

@@ -0,0 +1 @@
+- Place a household with no BRMA input in its region's BRMA with the most private-rented households, from the 2021 and 2022 censuses (Maidstone if the region is unknown), instead of Maidstone in every region. A household that sets no region is in London, the region default, so it now gets Inner South East London's LHA rates. A BRMA input still carries forward to later years while the household stays in the same region.

policyengine_uk/tests/policy/baseline/finance/benefit/family/LHA.yaml

@@ -1,13 +1,17 @@
+# With no region input the household is in London (region's default), so
+# brma defaults to London's BRMA rather than Maidstone, which it used for
+# every region before brma had a formula. Maidstone's rate here was 9,753.12.
 - name: BRMA default value
   period: 2020
   absolute_error_margin: 0.01
   input:
     age: 18
     LHA_category: C
   output:
-    brma: MAIDSTONE
-    # VOA, LHA April 2020 (amended), Table 4: Maidstone two bedrooms, GBP 187.56 a week.
-    BRMA_LHA_rate: 9_753.12
+    brma: INNER_SOUTH_EAST_LONDON
+    # VOA, LHA April 2020 (amended), Table 4: Inner South East London two
+    # bedrooms, GBP 310.68 a week.
+    BRMA_LHA_rate: 16_155.36
 - name: BRMA inputs
   period: 2020
   absolute_error_margin: 0

policyengine_uk/tests/policy/baseline/household/brma.yaml

@@ -0,0 +1,123 @@
+# A household with no BRMA input is placed in its region's BRMA with the most
+# private-rented households (REGION_DEFAULT_BRMA in
+# variables/household/BRMA.py). test_brma_region_default.py checks that the
+# default gives the same LHA rates as inputting that BRMA.
+
+- name: London household without a BRMA gets Inner South East London
+  period: 2025
+  input:
+    age: 40
+    region: LONDON
+    tenure_type: RENT_PRIVATELY
+    rent: 12_000
+  output:
+    brma: INNER_SOUTH_EAST_LONDON
+
+- name: Scottish household without a BRMA gets Lothian
+  period: 2025
+  input:
+    age: 40
+    region: SCOTLAND
+    tenure_type: RENT_PRIVATELY
+    rent: 12_000
+  output:
+    brma: LOTHIAN
+
+- name: Welsh household without a BRMA gets Cardiff
+  period: 2025
+  input:
+    age: 40
+    region: WALES
+    tenure_type: RENT_PRIVATELY
+    rent: 12_000
+  output:
+    brma: CARDIFF
+
+- name: Northern Ireland household without a BRMA gets Belfast
+  period: 2025
+  input:
+    age: 40
+    region: NORTHERN_IRELAND
+    tenure_type: RENT_PRIVATELY
+    rent: 12_000
+  output:
+    brma: BELFAST
+
+- name: An input BRMA overrides the region default
+  period: 2025
+  input:
+    age: 40
+    region: SCOTLAND
+    brma: GREATER_GLASGOW
+    tenure_type: RENT_PRIVATELY
+    rent: 12_000
+  output:
+    brma: GREATER_GLASGOW
+
+- name: An input BRMA outside the household's region is still used
+  period: 2025
+  input:
+    age: 40
+    region: LONDON
+    brma: MAIDSTONE
+    tenure_type: RENT_PRIVATELY
+    rent: 12_000
+  output:
+    brma: MAIDSTONE
+
+- name: Unknown region keeps Maidstone
+  period: 2025
+  input:
+    age: 40
+    region: UNKNOWN
+    tenure_type: RENT_PRIVATELY
+    rent: 12_000
+  output:
+    brma: MAIDSTONE
+
+- name: Every region without a BRMA gets its default
+  period: 2025
+  input:
+    people:
+      p1: {age: 40}
+      p2: {age: 40}
+      p3: {age: 40}
+      p4: {age: 40}
+      p5: {age: 40}
+      p6: {age: 40}
+      p7: {age: 40}
+      p8: {age: 40}
+      p9: {age: 40}
+      p10: {age: 40}
+      p11: {age: 40}
+      p12: {age: 40}
+      p13: {age: 40}
+    households:
+      h1: {members: [p1], region: NORTH_EAST}
+      h2: {members: [p2], region: NORTH_WEST}
+      h3: {members: [p3], region: YORKSHIRE}
+      h4: {members: [p4], region: EAST_MIDLANDS}
+      h5: {members: [p5], region: WEST_MIDLANDS}
+      h6: {members: [p6], region: EAST_OF_ENGLAND}
+      h7: {members: [p7], region: LONDON}
+      h8: {members: [p8], region: SOUTH_EAST}
+      h9: {members: [p9], region: SOUTH_WEST}
+      h10: {members: [p10], region: WALES}
+      h11: {members: [p11], region: SCOTLAND}
+      h12: {members: [p12], region: NORTHERN_IRELAND}
+      h13: {members: [p13], region: UNKNOWN}
+  output:
+    brma:
+      - TYNESIDE
+      - CENTRAL_GREATER_MANCHESTER
+      - LEEDS
+      - LEICESTER
+      - BIRMINGHAM
+      - CENTRAL_NORFOLK_NORWICH
+      - INNER_SOUTH_EAST_LONDON
+      - SOUTHAMPTON
+      - BRISTOL
+      - CARDIFF
+      - LOTHIAN
+      - BELFAST
+      - MAIDSTONE

policyengine_uk/tests/policy/integration/entitledto_scenarios.yaml

@@ -27,16 +27,20 @@
         region: LONDON
         country: ENGLAND
         tenure_type: RENT_PRIVATELY
+  # No BRMA is input, so the household gets London's default BRMA (Inner
+  # South East London) rather than Maidstone, which every household without
+  # a BRMA used before brma had a formula. A single person under 35 gets the
+  # shared accommodation rate, published for Universal Credit from April
+  # 2024 and held for 2025-26: GBP 650.00 a month for Inner South East
+  # London against GBP 444.83 for Maidstone. Universal Credit and net income
+  # rise by GBP 2,462.04 (from 3,539.64 and 14,165.10).
   output:
     income_tax: 0
     national_insurance: 0
-    # No BRMA is given, so the default (Maidstone) applies: a single person
-    # under 35 gets the shared accommodation rate, published at GBP 444.83 a
-    # month for Universal Credit from April 2024 and held for 2025-26.
-    universal_credit: 3_539.64
+    universal_credit: 6_001.68
     housing_benefit: 0
     child_benefit: 0
-    household_net_income: 14_165.10
+    household_net_income: 16_627.14
 
 - name: "EntitledTo #2 - couple with 2 children, one earner at £22k, social housing in North West"
   period: 2025