Record benefit-unit capital once; derive UC and Pension Credit reported capital from it

changelog.d/benunit-reported-capital.added.md

@@ -0,0 +1 @@
+- Added `benunit_reported_capital`, the benefit unit's recorded savings and investments (such as the FRS's TOTCAPB4; -1 when nothing is recorded). `uc_reported_capital` and `pension_credit_reported_capital` are now formulas that default to it, so a dataset records the observed capital once and each means test derives its own; either can still be set directly. The input uprates like `savings`, as does either programme variable when a dataset stores it directly. Results are unchanged for datasets and situations that do not supply the new input, except as noted under Changed.

changelog.d/benunit-reported-capital.changed.md

@@ -0,0 +1 @@
+- `uc_reported_capital` and `pension_credit_reported_capital` set directly in a situation now apply only to the years they are set, as for any formula variable; later years derive from `benunit_reported_capital`, which is uprated from the year it is set. Before, a value set for one year carried into later years (uprated, for Pension Credit). A dataset that stores `uc_reported_capital` now has it uprated by per-capita GDP, like `savings`, where it used to be held flat; stored `pension_credit_reported_capital` uprates as before.

policyengine_uk/data/uprating_indices.yaml

@@ -92,6 +92,7 @@ gov.economic_assumptions.yoy_growth.obr.per_capita.gdp:
 - capital_gains_badr
 - capital_gains_residential_property
 - capital_gains_carried_interest
+- benunit_reported_capital
 - corporate_wealth
 - dividend_income
 - gross_financial_wealth
@@ -107,6 +108,8 @@ gov.economic_assumptions.yoy_growth.obr.per_capita.gdp:
 - other_investment_income
 - other_residential_property_value
 - owned_land
+# A formula of benunit_reported_capital; listed so a dataset that stores it
+# directly is uprated like the input.
 - pension_credit_reported_capital
 - pension_income
 - private_pension_wealth
@@ -116,6 +119,9 @@ gov.economic_assumptions.yoy_growth.obr.per_capita.gdp:
 - savings
 - savings_interest_income
 - sublet_income
+# A formula of benunit_reported_capital; listed so a dataset that stores it
+# directly is uprated like the input.
+- uc_reported_capital
 gov.economic_assumptions.yoy_growth.obr.per_capita.mixed_income:
 - self_employment_income
 gov.economic_assumptions.yoy_growth.obr.private_pension_index:

policyengine_uk/parameters/gov/dwp/universal_credit/means_test/capital/sources.yaml

@@ -21,8 +21,9 @@ description: >
   benunits that are not themselves UC claimants. That proxy is a data
   approximation, not a legislated allocation rule. Regulation 47 is cited only
   as related context on jointly held capital. If some benunits provide
-  `uc_reported_capital`, the proxy is applied only to the residual household
-  capital for benunits that remain unreported.
+  `uc_reported_capital` (by default the benefit unit's recorded capital,
+  `benunit_reported_capital`), the proxy is applied only to the residual
+  household capital for benunits that remain unreported.
 metadata:
   label: Universal Credit countable capital sources
   period: year

policyengine_uk/tests/policy/baseline/household/wealth/benunit_reported_capital.yaml

@@ -0,0 +1,119 @@
+# benunit_reported_capital records the benefit unit's savings and investments
+# (-1 when nothing is recorded). Universal Credit (WRA 2012 s.5; UC Regulations
+# 2013 reg.18) and Pension Credit (SPCA 2002 s.5) assess the claimant's and
+# partner's capital together, so both programmes take the recorded figure in
+# place of the household capital proxy unless their own variable is set.
+# Tariff income: UC Regulations 2013 reg.72, 4.35 pounds a month for each 250
+# pounds or part above 6,000.
+
+- name: Recorded capital replaces the household proxy for both programmes.
+  period: 2025
+  input:
+    people:
+      claimant:
+        age: 30
+    benunits:
+      benunit:
+        members: [claimant]
+        benunit_reported_capital: 2_000
+    households:
+      household:
+        members: [claimant]
+        savings: 50_000
+  output:
+    uc_reported_capital: 2_000
+    pension_credit_reported_capital: 2_000
+    uc_assessable_capital: 2_000
+    is_uc_eligible: true
+
+- name: With nothing recorded the household proxy applies.
+  period: 2025
+  input:
+    people:
+      claimant:
+        age: 30
+    benunits:
+      benunit:
+        members: [claimant]
+    households:
+      household:
+        members: [claimant]
+        savings: 50_000
+  output:
+    benunit_reported_capital: -1
+    uc_reported_capital: -1
+    pension_credit_reported_capital: -1
+    uc_assessable_capital: 50_000
+    is_uc_eligible: false
+
+- name: A programme variable set directly overrides the recorded capital for that programme only.
+  period: 2025
+  input:
+    people:
+      claimant:
+        age: 30
+    benunits:
+      benunit:
+        members: [claimant]
+        benunit_reported_capital: 20_000
+        uc_reported_capital: 3_000
+    households:
+      household:
+        members: [claimant]
+        savings: 50_000
+  output:
+    uc_assessable_capital: 3_000
+    pension_credit_reported_capital: 20_000
+
+- name: Recorded capital sets UC tariff income.
+  period: 2025
+  input:
+    people:
+      claimant:
+        age: 30
+    benunits:
+      benunit:
+        members: [claimant]
+        benunit_reported_capital: 6_251
+    households:
+      household:
+        members: [claimant]
+        savings: 50_000
+  output:
+    uc_assessable_capital: 6_251
+    # 251 pounds above 6,000 is two steps: 2 * 4.35 * 12 = 104.40.
+    uc_tariff_income: 104.4
+
+- name: Recorded capital replaces the household proxy for Pension Credit.
+  period: 2025
+  input:
+    people:
+      pensioner:
+        age: 75
+    benunits:
+      benunit:
+        members: [pensioner]
+        benunit_reported_capital: 12_000
+    households:
+      household:
+        members: [pensioner]
+        savings: 200_000
+  output:
+    pension_credit_assessable_capital: 12_000
+
+- name: With nothing recorded Pension Credit uses the household proxy.
+  period: 2025
+  input:
+    people:
+      pensioner:
+        age: 75
+    benunits:
+      benunit:
+        members: [pensioner]
+    households:
+      household:
+        members: [pensioner]
+        savings: 200_000
+  output:
+    pension_credit_reported_capital: -1
+    pension_credit_assessable_capital: 200_000