Add national council tax reduction core

changelog.d/council-tax-reduction-national.md

@@ -0,0 +1 @@
+- Add national Council Tax Reduction support for Scotland, Wales, and English pensioner households, while preserving reported CTB/CTR for unsupported English working-age local schemes.

policyengine_uk/parameters/gov/local_authorities/england/council_tax_reduction/pensioners/maximum_support_rate.yaml

@@ -0,0 +1,10 @@
+description: Maximum share of eligible Council Tax liability covered for pensioner households under the England Council Tax Reduction scheme.
+values:
+  2013-04-01: 1
+metadata:
+  unit: /1
+  period: year
+  label: England Council Tax Reduction pensioner maximum support rate
+  reference:
+    - title: The Council Tax Reduction Schemes (Prescribed Requirements) (England) Regulations 2012
+      href: https://www.legislation.gov.uk/uksi/2012/2885/contents/made

policyengine_uk/parameters/gov/local_authorities/england/council_tax_reduction/pensioners/means_test/capital_limit.yaml

@@ -0,0 +1,10 @@
+description: Capital limit for pensioner households under the England Council Tax Reduction scheme.
+values:
+  2013-04-01: 16_000
+metadata:
+  unit: currency-GBP
+  period: year
+  label: England Council Tax Reduction pensioner capital limit
+  reference:
+    - title: The Council Tax Reduction Schemes (Prescribed Requirements) (England) Regulations 2012
+      href: https://www.legislation.gov.uk/uksi/2012/2885/contents/made

policyengine_uk/parameters/gov/local_authorities/england/council_tax_reduction/pensioners/means_test/withdrawal_rate.yaml

@@ -0,0 +1,10 @@
+description: Withdrawal rate for pensioner households under the England Council Tax Reduction scheme.
+values:
+  2013-04-01: 0.2
+metadata:
+  unit: /1
+  period: year
+  label: England Council Tax Reduction pensioner withdrawal rate
+  reference:
+    - title: The Council Tax Reduction Schemes (Prescribed Requirements) (England) Regulations 2012
+      href: https://www.legislation.gov.uk/uksi/2012/2885/contents/made

policyengine_uk/parameters/gov/local_authorities/scotland/council_tax_reduction/maximum_support_rate.yaml

@@ -0,0 +1,10 @@
+description: Maximum share of eligible Council Tax liability covered under the Scotland Council Tax Reduction scheme.
+values:
+  2013-04-01: 1
+metadata:
+  unit: /1
+  period: year
+  label: Scotland Council Tax Reduction maximum support rate
+  reference:
+    - title: The Council Tax Reduction (Scotland) Regulations 2012
+      href: https://www.legislation.gov.uk/ssi/2012/303/contents/made

policyengine_uk/parameters/gov/local_authorities/scotland/council_tax_reduction/means_test/capital_limit.yaml

@@ -0,0 +1,10 @@
+description: Capital limit under the Scotland Council Tax Reduction scheme.
+values:
+  2013-04-01: 16_000
+metadata:
+  unit: currency-GBP
+  period: year
+  label: Scotland Council Tax Reduction capital limit
+  reference:
+    - title: The Council Tax Reduction (Scotland) Regulations 2012
+      href: https://www.legislation.gov.uk/ssi/2012/303/contents/made

policyengine_uk/parameters/gov/local_authorities/scotland/council_tax_reduction/means_test/withdrawal_rate.yaml

@@ -0,0 +1,10 @@
+description: Withdrawal rate under the Scotland Council Tax Reduction scheme.
+values:
+  2013-04-01: 0.2
+metadata:
+  unit: /1
+  period: year
+  label: Scotland Council Tax Reduction withdrawal rate
+  reference:
+    - title: The Council Tax Reduction (Scotland) Regulations 2012
+      href: https://www.legislation.gov.uk/ssi/2012/303/contents/made

policyengine_uk/parameters/gov/local_authorities/wales/council_tax_reduction/maximum_support_rate.yaml

@@ -0,0 +1,10 @@
+description: Maximum share of eligible Council Tax liability covered under the Wales Council Tax Reduction scheme.
+values:
+  2013-04-01: 1
+metadata:
+  unit: /1
+  period: year
+  label: Wales Council Tax Reduction maximum support rate
+  reference:
+    - title: The Council Tax Reduction Schemes and Prescribed Requirements (Wales) Regulations 2012
+      href: https://www.legislation.gov.uk/wsi/2012/3144/contents/made

policyengine_uk/parameters/gov/local_authorities/wales/council_tax_reduction/means_test/capital_limit.yaml

@@ -0,0 +1,10 @@
+description: Capital limit under the Wales Council Tax Reduction scheme.
+values:
+  2013-04-01: 16_000
+metadata:
+  unit: currency-GBP
+  period: year
+  label: Wales Council Tax Reduction capital limit
+  reference:
+    - title: The Council Tax Reduction Schemes and Prescribed Requirements (Wales) Regulations 2012
+      href: https://www.legislation.gov.uk/wsi/2012/3144/contents/made

policyengine_uk/parameters/gov/local_authorities/wales/council_tax_reduction/means_test/withdrawal_rate.yaml

@@ -0,0 +1,10 @@
+description: Withdrawal rate under the Wales Council Tax Reduction scheme.
+values:
+  2013-04-01: 0.2
+metadata:
+  unit: /1
+  period: year
+  label: Wales Council Tax Reduction withdrawal rate
+  reference:
+    - title: The Council Tax Reduction Schemes and Prescribed Requirements (Wales) Regulations 2012
+      href: https://www.legislation.gov.uk/wsi/2012/3144/contents/made

policyengine_uk/programs.yaml

@@ -471,6 +471,18 @@ programs:
     variable: council_tax
     verified_start_year: 2022
 
+  - id: council_tax_reduction
+    name: Council Tax Reduction
+    full_name: Council Tax Reduction
+    category: Benefits
+    agency: Local
+    status: partial
+    coverage: UK
+    variable: council_tax_reduction
+    parameter_prefix: gov.local_authorities
+    verified_start_year: 2013
+    notes: First-pass national support for Scotland, Wales, and England pensioner schemes, with reported CTB/CTR retained for unsupported English working-age local schemes.
+
   # --- Treasury programs ---
   - id: cost_of_living_support
     name: Cost of Living Support

policyengine_uk/tests/policy/baseline/consumption/council_tax_less_benefit.yaml

@@ -0,0 +1,22 @@
+- name: Council Tax less reported fallback CTR is floored at zero
+  period: 2026
+  absolute_error_margin: 0
+  input:
+    people:
+      claimant:
+        age: 35
+        council_tax_benefit_reported: 2_500
+        employment_income: 10_000
+    benunits:
+      benunit:
+        members: [claimant]
+    households:
+      household:
+        members: [claimant]
+        country: ENGLAND
+        local_authority: MAIDSTONE
+        council_tax: 1_800
+        savings: 0
+  output:
+    council_tax_reduction: 2_500
+    council_tax_less_benefit: 0

policyengine_uk/tests/policy/baseline/gov/local_authorities/council_tax_reduction/council_tax_reduction.yaml

@@ -0,0 +1,95 @@
+- name: Unsupported English working-age schemes keep reported CTB
+  period: 2026
+  absolute_error_margin: 0
+  input:
+    people:
+      claimant:
+        age: 35
+        council_tax_benefit_reported: 500
+    benunits:
+      benunit:
+        members: [claimant]
+        would_claim_uc: false
+    households:
+      household:
+        members: [claimant]
+        country: ENGLAND
+        local_authority: MAIDSTONE
+        council_tax: 1_800
+        savings: 0
+  output:
+    council_tax_reduction_scheme_supported: false
+    simulated_council_tax_reduction_benunit: 0
+    council_tax_benefit: 500
+    council_tax_reduction: 500
+
+- name: Wales CTR simulates full support for a no-income claimant
+  period: 2026
+  absolute_error_margin: 0.01
+  input:
+    people:
+      claimant:
+        age: 35
+        council_tax_benefit_reported: 500
+    benunits:
+      benunit:
+        members: [claimant]
+        would_claim_uc: false
+    households:
+      household:
+        members: [claimant]
+        country: WALES
+        local_authority: CARDIFF
+        council_tax: 1_800
+        savings: 0
+  output:
+    council_tax_reduction_scheme_supported: true
+    simulated_council_tax_reduction_benunit: 1_800
+    council_tax_benefit: 1_800
+    council_tax_reduction: 1_800
+
+- name: Wales CTR applies the capital limit
+  period: 2026
+  absolute_error_margin: 0
+  input:
+    people:
+      claimant:
+        age: 35
+        council_tax_benefit_reported: 500
+    benunits:
+      benunit:
+        members: [claimant]
+    households:
+      household:
+        members: [claimant]
+        country: WALES
+        local_authority: CARDIFF
+        council_tax: 1_800
+        savings: 16_001
+  output:
+    council_tax_reduction_scheme_supported: true
+    simulated_council_tax_reduction_benunit: 0
+    council_tax_benefit: 0
+    council_tax_reduction: 0
+
+- name: England pensioner CTR is supported nationally
+  period: 2026
+  absolute_error_margin: 0.01
+  input:
+    people:
+      claimant:
+        age: 70
+    benunits:
+      benunit:
+        members: [claimant]
+    households:
+      household:
+        members: [claimant]
+        country: ENGLAND
+        local_authority: MAIDSTONE
+        council_tax: 1_800
+        savings: 0
+  output:
+    council_tax_reduction_scheme_supported: true
+    simulated_council_tax_reduction_benunit: 1_800
+    council_tax_reduction: 1_800

policyengine_uk/tests/policy/integration/entitledto_scenarios.yaml

@@ -93,7 +93,9 @@
     universal_credit: 0
     housing_benefit: 0
     pension_credit: 3_607.72
+    council_tax_reduction: 1_800
+    council_tax_less_benefit: 0
     winter_fuel_allowance: 200
     income_tax: 0
     national_insurance: 0
-    household_net_income: 15_833.18
+    household_net_income: 17_633.18

policyengine_uk/variables/gov/dwp/council_tax_benefit.py

@@ -8,4 +8,8 @@ class council_tax_benefit(Variable):
     definition_period = YEAR
     unit = GBP
 
-    adds = ["council_tax_benefit_reported"]
+    def formula(benunit, period, parameters):
+        supported = benunit.household("council_tax_reduction_scheme_supported", period)
+        simulated = benunit("simulated_council_tax_reduction_benunit", period)
+        reported = benunit("council_tax_benefit_reported", period)
+        return where(supported, simulated, reported)

policyengine_uk/variables/gov/local_authorities/council_tax_reduction/benunit_contains_household_head.py

@@ -0,0 +1,15 @@
+from policyengine_uk.model_api import *
+
+
+class benunit_contains_household_head(Variable):
+    value_type = bool
+    entity = BenUnit
+    label = "Benefit unit contains the oldest adult in the household"
+    definition_period = YEAR
+
+    def formula(benunit, period, parameters):
+        person = benunit.members
+        household = person.household
+        benunit_max_age = benunit.max(person("age", period))
+        household_max_age = benunit.max(household.max(person("age", period)))
+        return benunit_max_age == household_max_age

policyengine_uk/variables/gov/local_authorities/council_tax_reduction/config.py

@@ -0,0 +1,22 @@
+from policyengine_uk.model_api import *
+from policyengine_uk.variables.household.demographic.country import Country
+
+
+def is_england_pensioner_scheme(country, has_pensioner):
+    return (country == Country.ENGLAND) & has_pensioner
+
+
+def is_scotland_scheme(country):
+    return country == Country.SCOTLAND
+
+
+def is_wales_scheme(country):
+    return country == Country.WALES
+
+
+def is_supported_scheme(country, has_pensioner):
+    return (
+        is_england_pensioner_scheme(country, has_pensioner)
+        | is_scotland_scheme(country)
+        | is_wales_scheme(country)
+    )

policyengine_uk/variables/gov/local_authorities/council_tax_reduction/council_tax_reduction.py

@@ -0,0 +1,16 @@
+from policyengine_uk.model_api import *
+
+
+class council_tax_reduction(Variable):
+    value_type = float
+    entity = Household
+    label = "Council Tax Reduction"
+    definition_period = YEAR
+    unit = GBP
+
+    def formula(household, period, parameters):
+        person = household.members
+        return household.sum(
+            person.benunit("council_tax_benefit", period)
+            * person("is_benunit_head", period)
+        )

policyengine_uk/variables/gov/local_authorities/council_tax_reduction/council_tax_reduction_applicable_amount.py

@@ -0,0 +1,45 @@
+from policyengine_uk.model_api import *
+
+
+class council_tax_reduction_applicable_amount(Variable):
+    value_type = float
+    entity = BenUnit
+    label = "applicable Council Tax Reduction amount"
+    definition_period = YEAR
+    unit = GBP
+
+    def formula(benunit, period, parameters):
+        p = parameters(period).gov.dwp.housing_benefit.allowances
+        any_over_SP_age = benunit.any(benunit.members("is_SP_age", period))
+        eldest_age = benunit("eldest_adult_age", period)
+        older_age_threshold = p.age_threshold.older
+        younger_age_threshold = p.age_threshold.younger
+        u_18 = eldest_age < younger_age_threshold
+        u_25 = eldest_age < older_age_threshold
+        o_25 = (eldest_age >= older_age_threshold) & ~any_over_SP_age
+        o_18 = (eldest_age >= younger_age_threshold) & ~any_over_SP_age
+        single = benunit("is_single_person", period)
+        couple = benunit("is_couple", period)
+        lone_parent = benunit("is_lone_parent", period)
+        single_personal_allowance = (
+            u_25 * p.single.younger
+            + o_25 * p.single.older
+            + any_over_SP_age * p.single.aged
+        )
+        couple_personal_allowance = (
+            u_18 * p.couple.younger
+            + o_18 * p.couple.older
+            + any_over_SP_age * p.couple.aged
+        )
+        lone_parent_personal_allowance = (
+            u_18 * p.lone_parent.younger
+            + o_18 * p.lone_parent.older
+            + any_over_SP_age * p.lone_parent.aged
+        )
+        personal_allowance = (
+            single * single_personal_allowance
+            + couple * couple_personal_allowance
+            + lone_parent * lone_parent_personal_allowance
+        ) * WEEKS_IN_YEAR
+        premiums = benunit("benefits_premiums", period)
+        return personal_allowance + premiums