Add Housing Benefit special £20 earnings disregard

changelog.d/hb-special-disregard.added.md

@@ -0,0 +1 @@
+Added the Housing Benefit special standard earnings disregard with regime-specific qualifying routes, explicit residual pre-assessment and no stacking with ordinary amounts.

policyengine_uk/parameters/gov/dwp/housing_benefit/means_test/income_disregard/special.yaml

@@ -0,0 +1,16 @@
+description: Weekly Housing Benefit special standard earnings disregard, replacing the ordinary single or couple amount.
+values:
+  2015-04-01: 20
+metadata:
+  period: week
+  unit: currency-GBP
+  label: Housing Benefit special earnings disregard
+  reference:
+    - title: GB working-age earnings disregards, paragraphs 3 and 5 to 9
+      href: https://www.legislation.gov.uk/uksi/2006/213/schedule/4
+    - title: GB pension-age earnings disregards, paragraphs 1 to 7
+      href: https://www.legislation.gov.uk/uksi/2006/214/schedule/4
+    - title: NI working-age earnings disregards
+      href: https://www.legislation.gov.uk/nisr/2006/405/schedule/5
+    - title: NI pension-age earnings disregards
+      href: https://www.legislation.gov.uk/nisr/2006/406/schedule/5

policyengine_uk/tests/policy/baseline/finance/benefit/family/housing_benefit/applicable_income/housing_benefit_applicable_income_disregard.yaml

@@ -430,7 +430,7 @@
     # One member must work 30 hours; hours are not added across the couple.
     housing_benefit_applicable_income_disregard: 520 # £10 × 52
 
-- name: Disabled single person working 20 hours gets £5 plus the additional disregard (model limitation; the law gives £20 plus it)
+- name: Disabled single person working 20 hours gets £20 plus the additional disregard
   period: 2026
   absolute_error_margin: 0.01
   input:
@@ -448,15 +448,13 @@
     # Para 17(2)(b)(iv)(aa): a single claimant with the disability premium
     # working 16 hours or more meets the condition.
     meets_housing_benefit_additional_earnings_disregard_conditions: true
-    # KNOWN LIMITATION: the law gives £1,929.20. Intended model limitation.
-    # In law the same disability premium brings in
-    # the £20 disregard in place of £5: Sch 4 para 3(2), "This paragraph
-    # applies where the claimant's applicable amount includes an amount by
-    # way of the disability premium". The law gives (£20 + £17.10) × 52 =
-    # £1,929.20 (£8,000 ≥ £1,040 + £889.20). The £20 disregards are out of
-    # scope for this change and tracked as a follow-up; until then the model
-    # gives (£5 + £17.10) × 52.
-    housing_benefit_applicable_income_disregard: 1_149.20
+    # The disability premium gives the £20 standard disregard under Sch 4
+    # para 3(2), replacing £5. Net earnings cover that amount and the
+    # additional disregard: £8,000 ≥ £1,040 + £889.20.
+    # (£20 + £17.10) × 52 = £1,929.20.
+    # https://www.legislation.gov.uk/uksi/2006/213/schedule/4/paragraph/3
+    # https://www.legislation.gov.uk/uksi/2006/213/schedule/4/paragraph/17
+    housing_benefit_applicable_income_disregard: 1_929.20
 
 - name: Working-age claimant on Income Support has all earnings disregarded
   period: 2026

policyengine_uk/tests/policy/baseline/finance/benefit/family/housing_benefit/applicable_income/housing_benefit_special_disregard.yaml

@@ -0,0 +1,104 @@
+# Cases: working disability/severe; working carer-only; pension carer;
+# pension generic disability premium; pension/working DLA; non-dependant DLA;
+# pension/working blindness.
+- name: ENGLAND statutory regime distinguishes automatic qualifying routes
+  period: 2024
+  input:
+    country: [ENGLAND, ENGLAND, ENGLAND, ENGLAND, ENGLAND, ENGLAND, ENGLAND, ENGLAND, ENGLAND, ENGLAND]
+    housing_benefit_pension_age_regulations_apply: [false, false, false, true, true, true, false, true, true, false]
+    disability_premium: [100, 0, 0, 0, 100, 0, 0, 0, 0, 0]
+    severe_disability_premium: [0, 100, 0, 0, 0, 0, 0, 0, 0, 0]
+    carer_premium: [0, 0, 100, 100, 0, 0, 0, 0, 0, 0]
+    dla_sc: [0, 0, 0, 0, 0, 100, 100, 100, 0, 0]
+    dla_m: [0, 0, 0, 0, 0, 0, 0, 0, 0, 0]
+    pip_dl: [0, 0, 0, 0, 0, 0, 0, 0, 0, 0]
+    pip_m: [0, 0, 0, 0, 0, 0, 0, 0, 0, 0]
+    attendance_allowance: [0, 0, 0, 0, 0, 0, 0, 0, 0, 0]
+    armed_forces_independence_payment: [0, 0, 0, 0, 0, 0, 0, 0, 0, 0]
+    is_blind: [false, false, false, false, false, false, false, false, true, true]
+    is_claimant_or_partner: [true, true, true, true, true, true, true, false, true, true]
+    housing_benefit_net_earnings: [5000, 5000, 5000, 5000, 5000, 5000, 5000, 5000, 5000, 5000]
+    is_lone_parent: [false, false, false, false, false, false, false, false, false, false]
+    is_couple: [false, false, false, false, false, false, false, false, false, false]
+  output:
+    housing_benefit_special_earnings_disregard_eligible: [true, true, false, true, false, true, false, false, true, false]
+    housing_benefit_special_earnings_disregard: [1040, 1040, 260, 1040, 260, 1040, 260, 260, 1040, 260]
+
+# Cases: working disability/severe; working carer-only; pension carer;
+# pension generic disability premium; pension/working DLA; non-dependant DLA;
+# pension/working blindness.
+- name: NORTHERN_IRELAND statutory regime distinguishes automatic qualifying routes
+  period: 2024
+  input:
+    country: [NORTHERN_IRELAND, NORTHERN_IRELAND, NORTHERN_IRELAND, NORTHERN_IRELAND, NORTHERN_IRELAND, NORTHERN_IRELAND, NORTHERN_IRELAND, NORTHERN_IRELAND, NORTHERN_IRELAND, NORTHERN_IRELAND]
+    housing_benefit_pension_age_regulations_apply: [false, false, false, true, true, true, false, true, true, false]
+    disability_premium: [100, 0, 0, 0, 100, 0, 0, 0, 0, 0]
+    severe_disability_premium: [0, 100, 0, 0, 0, 0, 0, 0, 0, 0]
+    carer_premium: [0, 0, 100, 100, 0, 0, 0, 0, 0, 0]
+    dla_sc: [0, 0, 0, 0, 0, 100, 100, 100, 0, 0]
+    dla_m: [0, 0, 0, 0, 0, 0, 0, 0, 0, 0]
+    pip_dl: [0, 0, 0, 0, 0, 0, 0, 0, 0, 0]
+    pip_m: [0, 0, 0, 0, 0, 0, 0, 0, 0, 0]
+    attendance_allowance: [0, 0, 0, 0, 0, 0, 0, 0, 0, 0]
+    armed_forces_independence_payment: [0, 0, 0, 0, 0, 0, 0, 0, 0, 0]
+    is_blind: [false, false, false, false, false, false, false, false, true, true]
+    is_claimant_or_partner: [true, true, true, true, true, true, true, false, true, true]
+    housing_benefit_net_earnings: [5000, 5000, 5000, 5000, 5000, 5000, 5000, 5000, 5000, 5000]
+    is_lone_parent: [false, false, false, false, false, false, false, false, false, false]
+    is_couple: [false, false, false, false, false, false, false, false, false, false]
+  output:
+    housing_benefit_special_earnings_disregard_eligible: [true, true, false, true, false, true, false, false, true, false]
+    housing_benefit_special_earnings_disregard: [1040, 1040, 260, 1040, 260, 1040, 260, 260, 1040, 260]
+
+- name: Standard replacement, lone-parent precedence and earnings cap
+  period: 2024
+  input:
+    housing_benefit_special_earnings_disregard_eligible: [true, true, true, true, false, false]
+    housing_benefit_net_earnings: [5000, 5000, 5000, 500, 5000, 5000]
+    is_couple: [false, true, false, true, false, true]
+    is_lone_parent: [false, false, true, false, false, false]
+    housing_benefit_specified_or_temporary_accommodation_disregard: [0, 0, 0, 0, 0, 0]
+    housing_benefit_applicable_income_childcare_element: [0, 0, 0, 0, 0, 0]
+    meets_housing_benefit_additional_earnings_disregard_conditions: [false, false, false, false, false, false]
+    housing_benefit_on_passporting_benefit: [false, false, false, false, false, false]
+  output:
+    housing_benefit_applicable_income_disregard: [1040, 1040, 1300, 500, 260, 520]
+
+- name: Special standard amount participates in additional-disregard threshold
+  period: 2024
+  absolute_error_margin: 0.01
+  input:
+    housing_benefit_special_earnings_disregard_eligible: [true, true, true]
+    housing_benefit_net_earnings: [1929.19, 1929.20, 5000]
+    is_couple: [false, true, false]
+    is_lone_parent: [false, false, false]
+    housing_benefit_specified_or_temporary_accommodation_disregard: [0, 0, 0]
+    housing_benefit_applicable_income_childcare_element: [0, 0, 0]
+    meets_housing_benefit_additional_earnings_disregard_conditions: [true, true, true]
+    housing_benefit_on_passporting_benefit: [false, false, true]
+  output:
+    housing_benefit_applicable_income_disregard: [1040, 1929.20, 5000]
+
+- name: A zero special-amount reform is not replaced with the ordinary amount
+  period: 2024
+  input:
+    gov.dwp.housing_benefit.means_test.income_disregard.special: 0
+    housing_benefit_special_earnings_disregard_eligible: true
+    housing_benefit_net_earnings: 5000
+    is_lone_parent: false
+    is_couple: true
+  output:
+    housing_benefit_special_earnings_disregard: 0
+
+- name: Missing residual qualification preserves ordinary treatment
+  period: 2024
+  input:
+    disability_premium: 0
+    severe_disability_premium: 0
+    housing_benefit_pension_age_regulations_apply: false
+    housing_benefit_net_earnings: 5000
+    is_lone_parent: false
+    is_couple: false
+  output:
+    housing_benefit_special_earnings_disregard_eligible: false
+    housing_benefit_special_earnings_disregard: 260

policyengine_uk/tests/test_housing_benefit_earnings_disregard_properties.py

@@ -2,7 +2,8 @@
 
 SI 2006/213 Sch 4 (working age) and SI 2006/214 Sch 4 (pension age) disregard
 £25 a week of a lone parent's net earnings, £10 of a couple's and £5 of anyone
-else's, plus the £17.10 additional earnings disregard where a work condition
+else's, or £20 in place of the £5 or £10 for a family that qualifies for the
+special disregard (housing_benefit_special_earnings_disregard_eligible), plus the £17.10 additional earnings disregard where a work condition
 is met and net earnings at least equal the other disregards, the deductible
 childcare charges and £17.10. A claimant who, or whose partner, is on
 Universal Credit, Income Support, income-based JSA or income-related ESA has
@@ -28,11 +29,19 @@
    over, where nothing age-dependent (para 12, the age-25 test, National
    Insurance above State Pension age) can differ between the two groups, so
    it pins the current behaviour rather than independently testing the two
-   schedules.
+   schedules. Intended difference: the £20 special disregard has different
+   conditions at each age. At working age it follows the disability premium,
+   which the model grants on the disability flag the draws set; at pension age
+   it needs receipt of a listed benefit, blindness or the carer premium (SI
+   2006/214 Sch 4 paras 4 and 5), none of which the draws supply. The
+   comparison therefore covers families whose special eligibility is the same
+   at both ages, which includes every family without a disabled adult.
 7. Differential against the old flat formula (£5/£10/£25 by family type, plus
    £37.10 for summed hours over 30, or 16 for lone parents), read without
    CPI uprating. They agree for families whose net earnings cover the flat
-   amount and to whom neither formula gives the additional disregard. They
+   amount and to whom neither formula gives the additional disregard or the
+   special disregard; a couple or single person who qualifies for the special
+   disregard, and whose net earnings cover £20, gets £20 instead. They
    must differ where net earnings fall below the flat amount (the new
    disregard is the net earnings) and for families without earnings (the new
    disregard is zero).
@@ -159,6 +168,7 @@ def situation(units, earnings_bump=0.0, income_support=0.0, age_map=None):
     "housing_benefit_applicable_income",
     "housing_benefit_applicable_income_childcare_element",
     "meets_housing_benefit_additional_earnings_disregard_conditions",
+    "housing_benefit_special_earnings_disregard_eligible",
 ]
 
 
@@ -246,8 +256,13 @@ def test_pension_age_and_working_age_schedules_agree(units):
     # Map 25-60 onto 67-90, keeping everyone at or over 25.
     pension_age = calculate(units, age_map=lambda age: 67 + (age - 25) * 23 // 35)
     key = "housing_benefit_applicable_income_disregard"
+    special = "housing_benefit_special_earnings_disregard_eligible"
     for i, unit in enumerate(units):
-        assert abs(working_age[key][i] - pension_age[key][i]) < 0.01, unit
+        if not any(adult["disabled"] for adult in unit["adults"]):
+            # Nothing else in the draws can make the two routes differ.
+            assert working_age[special][i] == pension_age[special][i], unit
+        if working_age[special][i] == pension_age[special][i]:
+            assert abs(working_age[key][i] - pension_age[key][i]) < 0.01, unit
 
 
 @PROPERTY_SETTINGS
@@ -259,6 +274,7 @@ def test_differential_against_the_old_flat_formula(units):
     additional = values[
         "meets_housing_benefit_additional_earnings_disregard_conditions"
     ].astype(bool)
+    special = values["housing_benefit_special_earnings_disregard_eligible"].astype(bool)
     for i, unit in enumerate(units):
         old = old_flat_formula(unit)
         flat = OLD_FLAT[unit["shape"]] * WEEKS
@@ -272,8 +288,13 @@ def test_differential_against_the_old_flat_formula(units):
             assert abs(disregard[i] - net[i]) < 0.01, unit
             assert disregard[i] < old, unit
         elif not old_worker and not additional[i]:
-            # Agree: the flat amount, without CPI uprating.
-            assert abs(disregard[i] - old) < 0.01, unit
+            if special[i] and unit["shape"] != "lone_parent":
+                # Must differ: £20 replaces the flat £5 or £10 (lone parents
+                # keep £25, which takes precedence).
+                assert abs(disregard[i] - min(20 * WEEKS, net[i])) < 0.01, unit
+            else:
+                # Agree: the flat amount, without CPI uprating.
+                assert abs(disregard[i] - old) < 0.01, unit
 
 
 @PROPERTY_SETTINGS

policyengine_uk/tests/test_housing_benefit_specified_accommodation_disregard_properties.py

@@ -9,8 +9,8 @@
 claimant or lone parent under 25, £77.73 at 25 or over; for a couple £97.33
 where both are under 18, £61.53 where one is 18 or over but both are under
 25, and £119.70 where one is 25 or over. A couple has one amount. It is added
-to the £5/£10/£25 disregards (paras 10, 7 and 4), and para 17(3)(a) counts it
-in the £17.10 additional disregard's earnings test. The pension-age
+to the £5/£10/£20/£25 disregards (paras 10, 7, 3 and 4), and para 17(3)(a)
+counts it in the £17.10 additional disregard's earnings test. The pension-age
 Regulations (SI 2006/214; NI SR 2006/406) have no such disregard.
 
 Invariants, for 2027 (the first fiscal year the model reads with para 18 in
@@ -32,9 +32,12 @@
 5. Differential: the model agrees with a reference written from the
    statutory text. The reference is independent for the para 18 bands and
    gates (amounts hard-coded from the instrument, ages, family type, earner
-   and pension-age status from the generated inputs) and for how paras 4, 7,
-   10, 17 and 18 combine. It takes net earnings, deductible childcare and
-   the para 17(2) work condition from the model, which other tests cover.
+   and pension-age status from the generated inputs) and for how paras 3, 4,
+   7, 10, 17 and 18 combine. It takes net earnings, deductible childcare,
+   the para 17(2) work condition and whether the para 3 special £20 applies
+   from the model, which other tests cover
+   (test_housing_benefit_earnings_disregard_properties.py tests the special
+   £20).
    Explicit examples pin the age boundaries (couples aged 17/17, 17/18 and
    24/25; single claimants and lone parents aged 24 and 25).
 6. Scope: families whose claimant and partner are all over State Pension
@@ -80,6 +83,8 @@
 }
 # Paras 4, 7 and 10, and para 17.
 BASE_WEEKLY = {"single": 5, "lone_parent": 25, "couple": 10, "couple_with_children": 10}
+# Para 3: replaces the single or couple amount; a lone parent keeps £25.
+SPECIAL_WEEKLY = 20
 ADDITIONAL_WEEKLY = 17.10
 MAX_ANNUAL = (25 + COUPLE_25_PLUS + ADDITIONAL_WEEKLY) * WEEKS
 
@@ -198,6 +203,7 @@ def situation(units, earnings_bump=0.0, income_support=0.0, accommodation=None):
     "housing_benefit_applicable_income",
     "housing_benefit_applicable_income_childcare_element",
     "meets_housing_benefit_additional_earnings_disregard_conditions",
+    "housing_benefit_special_earnings_disregard_eligible",
     "housing_benefit_pension_age_regulations_apply",
 ]
 
@@ -229,10 +235,14 @@ def reference_para_18_weekly(unit):
     return SINGLE_25_PLUS if eldest >= 25 else SINGLE_UNDER_25
 
 
-def reference_disregard(unit, net, childcare, work_condition):
-    """Paras 4, 7, 10, 17 and 18 combined, from net earnings, the deductible
-    childcare charges and whether a para 17(2) work condition is met."""
-    standard = min(BASE_WEEKLY[unit["shape"]] * WEEKS, net)
+def reference_disregard(unit, net, childcare, work_condition, special=False):
+    """Paras 3, 4, 7, 10, 17 and 18 combined, from net earnings, the deductible
+    childcare charges, whether a para 17(2) work condition is met and whether
+    the para 3 special £20 applies."""
+    weekly = BASE_WEEKLY[unit["shape"]]
+    if special and unit["shape"] != "lone_parent":
+        weekly = SPECIAL_WEEKLY
+    standard = min(weekly * WEEKS, net)
     accommodation = min(reference_para_18_weekly(unit) * WEEKS, net - standard)
     additional = ADDITIONAL_WEEKLY * WEEKS
     covers = round(net, 2) >= round(
@@ -368,6 +378,9 @@ def test_differential_against_the_statutory_reference(units):
                     "meets_housing_benefit_additional_earnings_disregard_conditions"
                 ][i]
             ),
+            special=bool(
+                values["housing_benefit_special_earnings_disregard_eligible"][i]
+            ),
         )
         total = values["housing_benefit_applicable_income_disregard"][i]
         assert abs(total - expected) < 0.02, (unit, total, expected)

policyengine_uk/variables/gov/dwp/housing_benefit/applicable_income/housing_benefit_applicable_income_disregard.py

@@ -20,10 +20,11 @@ class housing_benefit_applicable_income_disregard(Variable):
         "(housing_benefit_on_passporting_benefit) has all earnings "
         "disregarded, at any age: the working-age Regulations then apply "
         "(SI 2006/213 reg 5(1)(b)). The "
-        "£20 disregards for disabled people, carers and some part-time "
-        "occupations are not modelled, nor is the working-age permitted work "
+        "£20 standard disregard uses established qualifying routes or an "
+        "explicit full-amount pre-assessment, without reconstructing partial "
+        "carer/occupation earnings allocations. The permitted-work "
         "disregard (Sch 4 para 10A), which replaces paras 3 to 10 but not "
-        "para 18."
+        "para 18, is not yet modelled here."
     )
     definition_period = YEAR
     unit = GBP
@@ -42,12 +43,7 @@ def formula(benunit, period, parameters):
         p = parameters(period).gov.dwp.housing_benefit.means_test.income_disregard
         net_earnings = benunit("housing_benefit_net_earnings", period)
         # Working age Sch 4 paras 4, 7 and 10; pension age Sch 4 paras 2 and 7.
-        weekly_amount = select(
-            [benunit("is_lone_parent", period), benunit("is_couple", period)],
-            [p.lone_parent, p.couple],
-            default=p.single,
-        )
-        standard = min_(weekly_amount * WEEKS_IN_YEAR, net_earnings)
+        standard = benunit("housing_benefit_special_earnings_disregard", period)
         # Working age Sch 4 para 18 (NI Sch 5 para 18), from 5 October 2026:
         # specified or temporary accommodation. It applies alongside paras 3
         # to 10A, none of which excludes it, and takes the earnings they