Improve statutory maternity, paternity and sick pay and SSMG uprating (#1190)

nikhilwoodruff · web-flow · commit 12bfc38fa596 · 2025-07-10T11:02:02.000+01:00
* Fix statutory sick, maternity and paternity pay and SSMG * Versioning * Fix Remove basic income from HBAI net income #1188 * Fix IIDB maximum rates are outdated #1174 * Update IIDB values * Fix SSMG value
diff --git a/changelog_entry.yaml b/changelog_entry.yaml
@@ -0,0 +1,5 @@
+- bump: minor
+  changes:
+    fixed:
+    - Statutory maternity, paternity, and sick pay variables now use the `gov.obr.consumer_price_index` for uprating.
+    - SSMG no longer is uprated by inflation.
diff --git a/policyengine_uk/data/__init__.py b/policyengine_uk/data/__init__.py
@@ -0,0 +1,5 @@
+from policyengine_uk.data.dataset_schema import UKDataset
+from policyengine_uk.data.economic_assumptions import (
+    BASELINE_GROWFACTORS,
+    apply_growth_factors,
+)
diff --git a/policyengine_uk/parameters/gov/dwp/IIDB/maximum.yaml b/policyengine_uk/parameters/gov/dwp/IIDB/maximum.yaml
@@ -6,5 +6,12 @@ metadata:
   label: Industrial Injuries Disablement Benefit maximum
   reference: https://www.gov.uk/industrial-injuries-disablement-benefit/what-youll-get
   unit: currency-GBP
+  uprating: gov.obr.consumer_price_index
 values:
   2015-04-01: 182
+  2025-04-01: 
+    value: 225.30
+    reference:
+    - title: GOV.UK
+      href: https://www.gov.uk/industrial-injuries-disablement-benefit/what-youll-get
+
diff --git a/policyengine_uk/parameters/gov/dwp/ssmg/rate.yaml b/policyengine_uk/parameters/gov/dwp/ssmg/rate.yaml
@@ -0,0 +1,8 @@
+description: Amount paid to recipients of the Sure Start Maternity Grant.
+values:
+  2022-01-01: 500
+metadata:
+  unit: currency-GBP
+  reference:
+    - title: GOV.UK
+      href: https://www.gov.uk/sure-start-maternity-grant/what-youll-get
diff --git a/policyengine_uk/tests/policy/baseline/gov/hmrc/national_insurance/class_1/ni_class_1_income.yaml b/policyengine_uk/tests/policy/baseline/gov/hmrc/national_insurance/class_1/ni_class_1_income.yaml
@@ -2,8 +2,8 @@
   period: 2023
   input:
     employment_income: 1
-    household_statutory_sick_pay: 2
-    household_statutory_maternity_pay: 4
-    household_statutory_paternity_pay: 8
+    statutory_sick_pay: 2
+    statutory_maternity_pay: 4
+    statutory_paternity_pay: 8
   output:
     ni_class_1_income: 15
diff --git a/policyengine_uk/variables/contrib/policyengine/employer_ni/adjusted_employer_cost.py b/policyengine_uk/variables/contrib/policyengine/employer_ni/adjusted_employer_cost.py
@@ -14,9 +14,9 @@ def formula(person, period, parameters):
             person,
             period,
             [
-                "household_statutory_sick_pay",
-                "household_statutory_maternity_pay",
-                "household_statutory_paternity_pay",
+                "statutory_sick_pay",
+                "statutory_maternity_pay",
+                "statutory_paternity_pay",
             ],
         )
         employer_pension_contributions = person(
diff --git a/policyengine_uk/variables/contrib/policyengine/employer_ni/baseline_employer_cost.py b/policyengine_uk/variables/contrib/policyengine/employer_ni/baseline_employer_cost.py
@@ -19,9 +19,9 @@ def formula(person, period, parameters):
             person,
             period,
             [
-                "household_statutory_sick_pay",
-                "household_statutory_maternity_pay",
-                "household_statutory_paternity_pay",
+                "statutory_sick_pay",
+                "statutory_maternity_pay",
+                "statutory_paternity_pay",
             ],
         )
         employer_pension_contributions = person(
diff --git a/policyengine_uk/variables/contrib/policyengine/employer_ni/employer_cost.py b/policyengine_uk/variables/contrib/policyengine/employer_ni/employer_cost.py
@@ -13,9 +13,9 @@ def formula(person, period, parameters):
             person,
             period,
             [
-                "household_statutory_sick_pay",
-                "household_statutory_maternity_pay",
-                "household_statutory_paternity_pay",
+                "statutory_sick_pay",
+                "statutory_maternity_pay",
+                "statutory_paternity_pay",
             ],
         )
         return (
diff --git a/policyengine_uk/variables/contrib/policyengine/employer_ni/employer_ni_fixed_employer_cost_change.py b/policyengine_uk/variables/contrib/policyengine/employer_ni/employer_ni_fixed_employer_cost_change.py
@@ -26,9 +26,9 @@ def formula(person, period, parameters):
             person,
             period,
             [
-                "household_statutory_sick_pay",
-                "household_statutory_maternity_pay",
-                "household_statutory_paternity_pay",
+                "statutory_sick_pay",
+                "statutory_maternity_pay",
+                "statutory_paternity_pay",
             ],
         )
         employer_pension_contributions = person(
diff --git a/policyengine_uk/variables/gov/dwp/maternity_allowance_reported.py b/policyengine_uk/variables/gov/dwp/maternity_allowance_reported.py
@@ -7,3 +7,4 @@ class maternity_allowance_reported(Variable):
     label = "Maternity allowance"
     definition_period = YEAR
     unit = GBP
+    uprating = "gov.obr.consumer_price_index"
diff --git a/policyengine_uk/variables/gov/dwp/ssmg.py b/policyengine_uk/variables/gov/dwp/ssmg.py
@@ -8,4 +8,6 @@ class ssmg(Variable):
     value_type = float
     unit = GBP
 
-    adds = ["ssmg_reported"]
+    def formula(person, period, parameters):
+        reported_receipt = person("ssmg_reported", period) > 0
+        return reported_receipt * parameters(period).gov.dwp.ssmg.rate
diff --git a/policyengine_uk/variables/gov/dwp/ssmg_reported.py b/policyengine_uk/variables/gov/dwp/ssmg_reported.py
@@ -7,4 +7,3 @@ class ssmg_reported(Variable):
     definition_period = YEAR
     value_type = float
     unit = GBP
-    uprating = "gov.obr.consumer_price_index"
diff --git a/policyengine_uk/variables/gov/hmrc/benefits/statutory_maternity_pay.py b/policyengine_uk/variables/gov/hmrc/benefits/statutory_maternity_pay.py
diff --git a/policyengine_uk/variables/gov/hmrc/benefits/statutory_sick_pay.py b/policyengine_uk/variables/gov/hmrc/benefits/statutory_sick_pay.py
diff --git a/policyengine_uk/variables/gov/hmrc/national_insurance/class_1/ni_class_1_income.py b/policyengine_uk/variables/gov/hmrc/national_insurance/class_1/ni_class_1_income.py
@@ -10,8 +10,8 @@ class ni_class_1_income(Variable):
     unit = GBP
     adds = [
         "employment_income",
-        "household_statutory_sick_pay",
-        "household_statutory_maternity_pay",
-        "household_statutory_paternity_pay",
+        "statutory_sick_pay",
+        "statutory_maternity_pay",
+        "statutory_paternity_pay",
     ]  # Employee pension contributions are not deducted
     reference = "https://www.legislation.gov.uk/ukpga/1992/4/section/3"
diff --git a/policyengine_uk/variables/household/income/hbai_household_net_income.py b/policyengine_uk/variables/household/income/hbai_household_net_income.py
@@ -47,7 +47,6 @@ class hbai_household_net_income(Variable):
         "statutory_sick_pay",
         "statutory_maternity_pay",
         "ssmg",
-        "basic_income",
         "cost_of_living_support_payment",
         "winter_fuel_allowance",
         "tax_free_childcare",
diff --git a/policyengine_uk/variables/household/income/statutory_maternity_pay.py b/policyengine_uk/variables/household/income/statutory_maternity_pay.py
@@ -3,9 +3,10 @@
 import numpy as np
 
 
-class household_statutory_maternity_pay(Variable):
+class statutory_maternity_pay(Variable):
     label = "Statutory maternity pay"
     entity = Person
     definition_period = YEAR
     value_type = float
     unit = GBP
+    uprating = "gov.obr.consumer_price_index"
diff --git a/policyengine_uk/variables/household/income/statutory_paternity_pay.py b/policyengine_uk/variables/household/income/statutory_paternity_pay.py
@@ -3,9 +3,10 @@
 import numpy as np
 
 
-class household_statutory_paternity_pay(Variable):
+class statutory_paternity_pay(Variable):
     label = "Statutory paternity pay"
     entity = Person
     definition_period = YEAR
     value_type = float
     unit = GBP
+    uprating = "gov.obr.consumer_price_index"
diff --git a/policyengine_uk/variables/household/income/statutory_sick_pay.py b/policyengine_uk/variables/household/income/statutory_sick_pay.py
@@ -3,9 +3,10 @@
 import numpy as np
 
 
-class household_statutory_sick_pay(Variable):
+class statutory_sick_pay(Variable):
     label = "Statutory sick pay"
     entity = Person
     definition_period = YEAR
     value_type = float
     unit = GBP
+    uprating = "gov.obr.consumer_price_index"

Original file line number	Diff line number	Diff line change
`@@ -14,9 +14,9 @@ def formula(person, period, parameters):`
`14`	`14`	`person,`
`15`	`15`	`period,`
`16`	`16`	`[`
`17`		`- "household_statutory_sick_pay",`
`18`		`- "household_statutory_maternity_pay",`
`19`		`- "household_statutory_paternity_pay",`
	`17`	`+ "statutory_sick_pay",`
	`18`	`+ "statutory_maternity_pay",`
	`19`	`+ "statutory_paternity_pay",`
`20`	`20`	`],`
`21`	`21`	`)`
`22`	`22`	`employer_pension_contributions = person(`
Original file line number	Diff line number	Diff line change
`@@ -19,9 +19,9 @@ def formula(person, period, parameters):`
`19`	`19`	`person,`
`20`	`20`	`period,`
`21`	`21`	`[`
`22`		`- "household_statutory_sick_pay",`
`23`		`- "household_statutory_maternity_pay",`
`24`		`- "household_statutory_paternity_pay",`
	`22`	`+ "statutory_sick_pay",`
	`23`	`+ "statutory_maternity_pay",`
	`24`	`+ "statutory_paternity_pay",`
`25`	`25`	`],`
`26`	`26`	`)`
`27`	`27`	`employer_pension_contributions = person(`
Original file line number	Diff line number	Diff line change
`@@ -13,9 +13,9 @@ def formula(person, period, parameters):`
`13`	`13`	`person,`
`14`	`14`	`period,`
`15`	`15`	`[`
`16`		`- "household_statutory_sick_pay",`
`17`		`- "household_statutory_maternity_pay",`
`18`		`- "household_statutory_paternity_pay",`
	`16`	`+ "statutory_sick_pay",`
	`17`	`+ "statutory_maternity_pay",`
	`18`	`+ "statutory_paternity_pay",`
`19`	`19`	`],`
`20`	`20`	`)`
`21`	`21`	`return (`
Original file line number	Diff line number	Diff line change
`@@ -26,9 +26,9 @@ def formula(person, period, parameters):`
`26`	`26`	`person,`
`27`	`27`	`period,`
`28`	`28`	`[`
`29`		`- "household_statutory_sick_pay",`
`30`		`- "household_statutory_maternity_pay",`
`31`		`- "household_statutory_paternity_pay",`
	`29`	`+ "statutory_sick_pay",`
	`30`	`+ "statutory_maternity_pay",`
	`31`	`+ "statutory_paternity_pay",`
`32`	`32`	`],`
`33`	`33`	`)`
`34`	`34`	`employer_pension_contributions = person(`