Give the legacy severe disability premium its statutory conditions (stacked on #1896)

changelog.d/working-age-severe-disability-premium.changed.md

@@ -0,0 +1 @@
+- Read Attendance Allowance from its dataset award category when supplied, retained an explicitly approximate amount fallback otherwise, and applied Northern Ireland's separate AFIP and PIP commencement dates to the legacy severe disability premium.

changelog.d/working-age-severe-disability-premium.fixed.md

@@ -0,0 +1 @@
+The legacy benefit severe disability premium now qualifies on the benefits the Regulations list (Attendance Allowance, the DLA care component at the middle or highest rate, the PIP daily living component at either rate, and Armed Forces Independence Payment), pays a couple only when both partners qualify or the other partner is blind, pays the single rate when a carer benefit is paid for one partner, and is barred by a non-dependant aged 18 or over or by a carer benefit paid for the claimant. The tax credit severe disability flag now counts higher-rate Attendance Allowance and Armed Forces Independence Payment instead of all Armed Forces Compensation Scheme payments.

policyengine_uk/parameters/gov/dwp/disability_premia/severe_non_dependant_age.yaml

@@ -0,0 +1,15 @@
+description: >
+  A claimant loses the legacy severe disability premium if a non-dependant of
+  at least this age normally resides with them, unless that non-dependant
+  receives a severe disability premium qualifying benefit or is blind.
+metadata:
+  label: Legacy benefit severe disability premium non-dependant age
+  period: year
+  unit: year
+  reference:
+    - title: The Housing Benefit Regulations 2006 Sch. 3 para. 14(2)(a)(ii), (2)(b)(iii)
+      href: https://www.legislation.gov.uk/uksi/2006/213/schedule/3/paragraph/14
+    - title: The Income Support (General) Regulations 1987 Sch. 2 para. 13(2)(a)(ii), (2)(b)(iii)
+      href: https://www.legislation.gov.uk/uksi/1987/1967/schedule/2/paragraph/13
+values:
+  2006-03-06: 18

policyengine_uk/parameters/gov/dwp/disability_premia/severe_qualifying_benefits.yaml

@@ -0,0 +1,43 @@
+description: >
+  Benefits whose receipt makes a claimant or partner severely disabled for the
+  legacy severe disability premium, and whose receipt by a non-dependant means
+  that non-dependant is ignored in the premium's residence condition. The
+  Regulations list attendance allowance (either rate), the care component of
+  disability living allowance at the highest or middle rate, the daily living
+  component of personal independence payment at either rate, armed forces
+  independence payment, and the Scottish equivalents. The Scottish benefits
+  are not separate model variables, and the lists differ slightly between
+  instruments. The 8 April 2013 date is Great Britain's: S.I. 2013/388 added
+  the PIP daily living component and S.I. 2013/591 added armed forces
+  independence payment. This list applies in Great Britain; the
+  severe_qualifying_benefits_northern_ireland parameter holds Northern
+  Ireland's separate commencement dates. The model selects the list using
+  household country. Like other parameters, it reads the list as at 30 April
+  of each year from 2015 and at 1 January before that, and does not prorate a
+  change made during a year.
+metadata:
+  label: Legacy benefit severe disability premium qualifying benefits
+  period: year
+  unit: list
+  reference:
+    - title: The Housing Benefit Regulations 2006 Sch. 3 para. 14(2)(a)(i)
+      href: https://www.legislation.gov.uk/uksi/2006/213/schedule/3/paragraph/14
+    - title: The Income Support (General) Regulations 1987 Sch. 2 para. 13(2)(a)(i)
+      href: https://www.legislation.gov.uk/uksi/1987/1967/schedule/2/paragraph/13
+    - title: The Employment and Support Allowance Regulations 2008 Sch. 4 para. 6(2)(a)(i)
+      href: https://www.legislation.gov.uk/uksi/2008/794/schedule/4/paragraph/6
+    - title: The Jobseeker's Allowance Regulations 1996 Sch. 1 para. 15(1)(a), (2)(a), (4)(a)
+      href: https://www.legislation.gov.uk/uksi/1996/207/schedule/1/paragraph/15
+    - title: The Personal Independence Payment (Supplementary Provisions and Consequential Amendments) Regulations 2013 reg. 2
+      href: https://www.legislation.gov.uk/uksi/2013/388/regulation/2
+    - title: "The Armed Forces and Reserve Forces Compensation Scheme (Consequential Provisions: Subordinate Legislation) Order 2013 art. 2"
+      href: https://www.legislation.gov.uk/uksi/2013/591/article/2
+values:
+  2006-03-06:
+    - attendance_allowance
+    - dla_sc_middle_plus
+  2013-04-08:
+    - attendance_allowance
+    - dla_sc_middle_plus
+    - pip_dl
+    - armed_forces_independence_payment

policyengine_uk/parameters/gov/dwp/disability_premia/severe_qualifying_benefits_northern_ireland.yaml

@@ -0,0 +1,57 @@
+description: >
+  Benefits whose receipt qualifies a claimant or partner for the legacy severe
+  disability premium, or exempts a non-dependant from its residence condition,
+  in Northern Ireland. Attendance allowance at either rate and the disability
+  living allowance care component at the middle or highest rate qualify.
+  Armed forces independence payment was added from 24 December 2013 by
+  S.I. 2013/3021, and the personal independence payment daily living component
+  at either rate from 20 June 2016 by S.R. 2016/228. The amendments cover the
+  Northern Ireland Income Support, Jobseeker's Allowance, Housing Benefit and
+  Employment and Support Allowance regulations. Like other parameters, the model
+  reads the list as at 30 April of each year from 2015 and at 1 January before
+  that, and does not prorate a change made during a year. The initial value
+  date follows the shared model baseline, not the commencement of S.R.
+  2006/405 on 20 November 2006. Northern Ireland historical coverage before
+  that commencement has not been verified.
+metadata:
+  label: Northern Ireland legacy severe disability premium qualifying benefits
+  period: year
+  unit: list
+  reference:
+    - title: The Housing Benefit Regulations (Northern Ireland) 2006 reg. 1(1)
+      href: https://www.legislation.gov.uk/nisr/2006/405/regulation/1/made
+    - title: The Housing Benefit Regulations (Northern Ireland) 2006 Sch. 4 para. 14
+      href: https://www.legislation.gov.uk/nisr/2006/405/schedule/4/paragraph/14
+    - title: S.I. 2013/3021 art. 1 (commencement)
+      href: https://www.legislation.gov.uk/uksi/2013/3021/article/1
+    - title: S.I. 2013/3021 art. 14(5)(c) (Income Support)
+      href: https://www.legislation.gov.uk/uksi/2013/3021/article/14/5/c
+    - title: S.I. 2013/3021 art. 17(7)(c) (Jobseeker's Allowance)
+      href: https://www.legislation.gov.uk/uksi/2013/3021/article/17/7/c
+    - title: S.I. 2013/3021 art. 26(6)(c) (Housing Benefit)
+      href: https://www.legislation.gov.uk/uksi/2013/3021/article/26/6/c
+    - title: S.I. 2013/3021 art. 28(5)(b) (Employment and Support Allowance)
+      href: https://www.legislation.gov.uk/uksi/2013/3021/article/28/5/b
+    - title: S.R. 2016/228 reg. 1 (commencement)
+      href: https://www.legislation.gov.uk/nisr/2016/228/regulation/1
+    - title: S.R. 2016/228 reg. 11(5)(c) (Income Support)
+      href: https://www.legislation.gov.uk/nisr/2016/228/regulation/11/5/c
+    - title: S.R. 2016/228 reg. 14(7)(c) (Jobseeker's Allowance)
+      href: https://www.legislation.gov.uk/nisr/2016/228/regulation/14/7/c
+    - title: S.R. 2016/228 reg. 30(7)(c) (Housing Benefit)
+      href: https://www.legislation.gov.uk/nisr/2016/228/regulation/30/7/c
+    - title: S.R. 2016/228 reg. 34(5)(b) (Employment and Support Allowance)
+      href: https://www.legislation.gov.uk/nisr/2016/228/regulation/34/5/b
+values:
+  2006-03-06:
+    - attendance_allowance
+    - dla_sc_middle_plus
+  2013-12-24:
+    - attendance_allowance
+    - dla_sc_middle_plus
+    - armed_forces_independence_payment
+  2016-06-20:
+    - attendance_allowance
+    - dla_sc_middle_plus
+    - pip_dl
+    - armed_forces_independence_payment

policyengine_uk/tests/policy/baseline/finance/benefit/family/income_support/legacy_premiums.yaml

@@ -14,6 +14,7 @@
     is_disabled_for_benefits: true
     is_enhanced_disabled_for_benefits: true
     is_severely_disabled_for_benefits: true
+    pip_dl_category: ENHANCED
   output:
     # The claimant qualifies in their own right: no statutory age-18 floor.
     disability_premium: 2332.20
@@ -28,6 +29,7 @@
     is_disabled_for_benefits: true
     is_enhanced_disabled_for_benefits: true
     is_severely_disabled_for_benefits: true
+    pip_dl_category: ENHANCED
   output:
     disability_premium: 2332.20
     enhanced_disability_premium: 1144
@@ -46,6 +48,7 @@
         is_disabled_for_benefits: true
         is_enhanced_disabled_for_benefits: true
         is_severely_disabled_for_benefits: true
+        pip_dl_category: ENHANCED
     benunits:
       family:
         members: [parent, young_person]
@@ -66,9 +69,11 @@
       young_person:
         age: 19
         is_in_non_advanced_education: true
+        age_started_or_accepted_current_education_or_training: 17
         is_disabled_for_benefits: true
         is_enhanced_disabled_for_benefits: true
         is_severely_disabled_for_benefits: true
+        pip_dl_category: ENHANCED
     benunits:
       family:
         members: [parent, young_person]
@@ -91,16 +96,17 @@
         is_disabled_for_benefits: true
         is_enhanced_disabled_for_benefits: true
         is_severely_disabled_for_benefits: true
+        pip_dl_category: ENHANCED
     benunits:
       family:
         members: [claimant, partner]
   output:
     disability_premium: 3328
     enhanced_disability_premium: 1632.80
-    # Deliberately preserve the existing severe-premium approximation:
-    # one qualifying partner currently triggers the full couple rate.
-    # IS Sch 2 para 13 / HB Sch 3 para 14 require both to qualify.
-    severe_disability_premium: 8949.20
+    # IS Sch 2 para 13(2)(b) / HB Sch 3 para 14(2)(b) require both partners
+    # to qualify; the claimant receives no qualifying benefit and is not
+    # blind, so there is no severe disability premium.
+    severe_disability_premium: 0
 
 - name: Disabled lone parent with a young person keeps single legacy premiums
   period: 2026
@@ -113,9 +119,11 @@
         is_disabled_for_benefits: true
         is_enhanced_disabled_for_benefits: true
         is_severely_disabled_for_benefits: true
+        pip_dl_category: ENHANCED
       young_person:
         age: 19
         is_in_non_advanced_education: true
+        age_started_or_accepted_current_education_or_training: 17
     benunits:
       family:
         members: [parent, young_person]
@@ -136,6 +144,7 @@
         is_disabled_for_benefits: true
         is_enhanced_disabled_for_benefits: true
         is_severely_disabled_for_benefits: true
+        pip_dl_category: ENHANCED
     benunits:
       family:
         members: [parent, child]
@@ -154,11 +163,13 @@
         is_disabled_for_benefits: true
         is_enhanced_disabled_for_benefits: true
         is_severely_disabled_for_benefits: true
+        pip_dl_category: ENHANCED
       partner:
         age: 32
         is_disabled_for_benefits: true
         is_enhanced_disabled_for_benefits: true
         is_severely_disabled_for_benefits: true
+        pip_dl_category: ENHANCED
     benunits:
       family:
         members: [claimant, partner]

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

@@ -0,0 +1,111 @@
+# Severe disability conditions of the Child Tax Credit disability element
+# (CTC Regs 2002 reg 8(1)(b), (3)-(5)) and the Working Tax Credit severe
+# disability element (WTC Regs 2002 reg 17(2)-(4)).
+
+- name: DLA care component at the highest rate is severe
+  period: 2026
+  input:
+    dla_sc_category: HIGHER
+  output:
+    is_severely_disabled_for_benefits: true
+
+- name: DLA care component at the middle rate is not severe
+  period: 2026
+  input:
+    dla_sc_category: MIDDLE
+  output:
+    is_severely_disabled_for_benefits: false
+
+- name: PIP daily living component at the enhanced rate is severe
+  period: 2026
+  input:
+    pip_dl_category: ENHANCED
+  output:
+    is_severely_disabled_for_benefits: true
+
+- name: PIP daily living component at the standard rate is not severe
+  period: 2026
+  input:
+    pip_dl_category: STANDARD
+  output:
+    is_severely_disabled_for_benefits: false
+
+- name: Attendance Allowance at the higher rate is severe (WTC reg 17(2))
+  period: 2026
+  input:
+    aa_category: HIGHER
+  output:
+    is_severely_disabled_for_benefits: true
+
+- name: Attendance Allowance at the lower rate is not severe
+  period: 2026
+  input:
+    aa_category: LOWER
+  output:
+    is_severely_disabled_for_benefits: false
+
+- name: Armed Forces Independence Payment is severe
+  period: 2026
+  input:
+    armed_forces_independence_payment: 1_000
+  output:
+    is_severely_disabled_for_benefits: true
+
+- name: Other Armed Forces Compensation Scheme payments are not severe
+  period: 2026
+  input:
+    afcs_reported: 1_000
+  output:
+    is_severely_disabled_for_benefits: false
+
+- name: WTC severe disability element for a claimant on higher-rate Attendance Allowance
+  period: 2024
+  absolute_error_margin: 0.01
+  input:
+    age: 70
+    aa_category: HIGHER
+    is_WTC_eligible: true
+  output:
+    # WTC Regs 2002 reg 17(2) and Sch 2 para 6: 1,705 a year in 2024-25.
+    WTC_severely_disabled_element: 1_705
+
+# Attendance Allowance is read from its award category. Only when no category
+# is given is an amount compared with the annual higher rate less GBP 10 a
+# week: an approximation, since WTC reg 17(2) has no tolerance.
+- name: The Attendance Allowance category decides over an amount entered with it
+  period: 2026
+  input:
+    aa_category: LOWER
+    attendance_allowance: 5_959.20
+  output:
+    is_severely_disabled_for_benefits: false
+
+- name: Attendance Allowance amount with no category, at the 2024 threshold, is severe
+  period: 2024
+  input:
+    # 108.55 x 52 - 10 x 52 = 5,124.60.
+    attendance_allowance: 5_124.60
+  output:
+    is_severely_disabled_for_benefits: true
+
+- name: Attendance Allowance amount with no category, just below the 2024 threshold, is not severe
+  period: 2024
+  input:
+    attendance_allowance: 5_124.59
+  output:
+    is_severely_disabled_for_benefits: false
+
+- name: Attendance Allowance amount with no category, at the 2026 threshold, is severe
+  period: 2026
+  input:
+    # 114.60 x 52 - 10 x 52 = 5,439.20.
+    attendance_allowance: 5_439.20
+  output:
+    is_severely_disabled_for_benefits: true
+
+- name: Attendance Allowance amount with no category, just below the 2026 threshold, is not severe
+  period: 2026
+  input:
+    attendance_allowance: 5_439.19
+  output:
+    is_severely_disabled_for_benefits: false