[codex] Add Illinois SB3567 child tax credit contrib reform

changelog.d/il-sb3567.added.md

@@ -0,0 +1 @@
+- Add an Illinois SB3567 (104th General Assembly) contributed reform, opt-in via `gov.contrib.states.il.sb3567.in_effect`, that boosts the child tax credit for low-AGI filers.

policyengine_us/parameters/gov/contrib/states/il/sb3567/in_effect.yaml

@@ -0,0 +1,12 @@
+description: Illinois SB3567 modifies the child tax credit formula and makes the credit nonrefundable if this is true.
+
+values:
+  0000-01-01: false
+
+metadata:
+  unit: bool
+  period: year
+  label: Illinois SB3567 child tax credit reform in effect
+  reference:
+    - title: Illinois SB3567 (104th General Assembly) full text
+      href: https://ilga.gov/Legislation/BillStatus/FullText?DocNum=3567&DocTypeID=SB&GAID=18&LegId=166617&Print=1&SessionID=114

policyengine_us/reforms/reforms.py

@@ -236,6 +236,9 @@
 from .states.id.s1450 import (
     create_id_s1450_reform,
 )
+from .states.il.sb3567 import (
+    create_il_sb3567_reform,
+)
 from .states.ky.eitc import (
     create_ky_eitc_reform,
 )
@@ -440,6 +443,7 @@ def create_structural_reforms_from_parameters(parameters, period):
     ga_eitc = create_ga_eitc_reform(parameters, period)
     id_eitc = create_id_eitc_reform(parameters, period)
     id_s1450 = create_id_s1450_reform(parameters, period)
+    il_sb3567 = create_il_sb3567_reform(parameters, period)
     ky_eitc = create_ky_eitc_reform(parameters, period)
     ms_eitc = create_ms_eitc_reform(parameters, period)
     nd_eitc = create_nd_eitc_reform(parameters, period)
@@ -553,6 +557,7 @@ def create_structural_reforms_from_parameters(parameters, period):
         ga_eitc,
         id_eitc,
         id_s1450,
+        il_sb3567,
         ky_eitc,
         ms_eitc,
         nd_eitc,

policyengine_us/reforms/states/il/__init__.py

@@ -0,0 +1 @@
+from .sb3567 import create_il_sb3567_reform

policyengine_us/reforms/states/il/sb3567/__init__.py

@@ -0,0 +1,5 @@
+from .il_sb3567_reform import (
+    create_il_sb3567,
+    create_il_sb3567_reform,
+    il_sb3567,
+)

policyengine_us/reforms/states/il/sb3567/il_sb3567_reform.py

@@ -0,0 +1,78 @@
+from policyengine_core.periods import period as period_
+from policyengine_us.model_api import *
+
+
+def create_il_sb3567() -> Reform:
+    class il_ctc(Variable):
+        value_type = float
+        entity = TaxUnit
+        label = "Illinois Child Tax Credit"
+        unit = USD
+        definition_period = YEAR
+        reference = (
+            "https://ilga.gov/Legislation/BillStatus/FullText?DocNum=3567&DocTypeID=SB&GAID=18&LegId=166617&Print=1&SessionID=114",
+            "https://www.ilga.gov/legislation/ilcs/fulltext.asp?DocName=003500050K244",
+        )
+        defined_for = StateCode.IL
+
+        def formula(tax_unit, period, parameters):
+            p = parameters(period).gov.states.il.tax.income.credits
+            ctc = p.ctc
+            person = tax_unit.members
+            age = person("age", period)
+            age_eligible_child = age < ctc.age_limit
+            federal_ctc_eligible_child = person("ctc_qualifying_child", period)
+            eligible_child = age_eligible_child & federal_ctc_eligible_child
+            eligible_child_present = tax_unit.any(eligible_child)
+
+            actual_credit = tax_unit("il_eitc", period) * ctc.rate
+
+            # SB3567 keys the maximum credit amount to the dependent count.
+            # The bill cites IRC § 152, but here we use the tax unit's child
+            # dependent count, capped at 3 to match the federal EITC schedule.
+            dependent_count = min_(tax_unit("tax_unit_child_dependents", period), 3)
+            federal_eitc = parameters(period).gov.irs.credits.eitc
+            federal_maximum = federal_eitc.max.calc(dependent_count)
+            phase_in_rate = federal_eitc.phase_in_rate.calc(dependent_count)
+
+            # The bill's "income threshold to qualify for the maximum federal
+            # EITC" is the end of the phase-in range (start of the plateau).
+            max_federal_eitc_threshold = federal_maximum / phase_in_rate
+            max_credit = federal_maximum * p.eitc.match * ctc.rate
+
+            agi = tax_unit("adjusted_gross_income", period)
+            return eligible_child_present * where(
+                agi <= max_federal_eitc_threshold,
+                max_credit,
+                actual_credit,
+            )
+
+    class reform(Reform):
+        def apply(self):
+            self.update_variable(il_ctc)
+
+    return reform
+
+
+def create_il_sb3567_reform(parameters, period, bypass: bool = False):
+    if bypass:
+        return create_il_sb3567()
+
+    p = parameters.gov.contrib.states.il.sb3567
+
+    reform_active = False
+    current_period = period_(period)
+
+    for _ in range(5):
+        if p(current_period).in_effect:
+            reform_active = True
+            break
+        current_period = current_period.offset(1, "year")
+
+    if reform_active:
+        return create_il_sb3567()
+    else:
+        return None
+
+
+il_sb3567 = create_il_sb3567_reform(None, None, bypass=True)

policyengine_us/tests/policy/contrib/states/il/sb3567/il_sb3567.yaml

@@ -0,0 +1,256 @@
+- name: SB3567 boosts phase-in filers to the maximum one-child credit
+  period: 2025
+  absolute_error_margin: 0.01
+  reforms: policyengine_us.reforms.states.il.sb3567.il_sb3567
+  input:
+    gov.contrib.states.il.sb3567.in_effect: true
+    people:
+      filer:
+        age: 30
+      child:
+        age: 8
+        ctc_qualifying_child: true
+        is_tax_unit_dependent: true
+    tax_units:
+      tax_unit:
+        members: [filer, child]
+        adjusted_gross_income: 12_000
+        il_eitc: 200
+    households:
+      household:
+        members: [filer, child]
+        state_code: IL
+  output:
+    il_ctc: 346.24
+
+- name: SB3567 uses the three-child EITC maximum for larger dependent counts
+  period: 2025
+  absolute_error_margin: 0.01
+  reforms: policyengine_us.reforms.states.il.sb3567.il_sb3567
+  input:
+    gov.contrib.states.il.sb3567.in_effect: true
+    people:
+      filer:
+        age: 32
+      child1:
+        age: 9
+        ctc_qualifying_child: true
+        is_tax_unit_dependent: true
+      child2:
+        age: 7
+        is_tax_unit_dependent: true
+      child3:
+        age: 5
+        is_tax_unit_dependent: true
+      child4:
+        age: 3
+        is_tax_unit_dependent: true
+    tax_units:
+      tax_unit:
+        members: [filer, child1, child2, child3, child4]
+        adjusted_gross_income: 15_000
+        il_eitc: 400
+    households:
+      household:
+        members: [filer, child1, child2, child3, child4]
+        state_code: IL
+  output:
+    il_ctc: 643.68
+
+- name: SB3567 keeps plateau filers on the actual Illinois EITC amount
+  period: 2025
+  absolute_error_margin: 0.01
+  reforms: policyengine_us.reforms.states.il.sb3567.il_sb3567
+  input:
+    gov.contrib.states.il.sb3567.in_effect: true
+    people:
+      filer:
+        age: 33
+      child:
+        age: 6
+        ctc_qualifying_child: true
+        is_tax_unit_dependent: true
+    tax_units:
+      tax_unit:
+        members: [filer, child]
+        adjusted_gross_income: 18_000
+        il_eitc: 865.6
+    households:
+      household:
+        members: [filer, child]
+        state_code: IL
+  output:
+    il_ctc: 346.24
+
+- name: SB3567 keeps phase-out filers on 40 percent of actual Illinois EITC
+  period: 2025
+  absolute_error_margin: 0.01
+  reforms: policyengine_us.reforms.states.il.sb3567.il_sb3567
+  input:
+    gov.contrib.states.il.sb3567.in_effect: true
+    people:
+      filer:
+        age: 34
+      child:
+        age: 4
+        ctc_qualifying_child: true
+        is_tax_unit_dependent: true
+    tax_units:
+      tax_unit:
+        members: [filer, child]
+        adjusted_gross_income: 30_000
+        il_eitc: 300
+    households:
+      household:
+        members: [filer, child]
+        state_code: IL
+  output:
+    il_ctc: 120
+
+- name: SB3567 keeps the age-under-12 eligibility gate
+  period: 2025
+  absolute_error_margin: 0.01
+  reforms: policyengine_us.reforms.states.il.sb3567.il_sb3567
+  input:
+    gov.contrib.states.il.sb3567.in_effect: true
+    people:
+      filer:
+        age: 35
+      child:
+        age: 12
+        ctc_qualifying_child: true
+        is_tax_unit_dependent: true
+    tax_units:
+      tax_unit:
+        members: [filer, child]
+        adjusted_gross_income: 10_000
+        il_eitc: 200
+    households:
+      household:
+        members: [filer, child]
+        state_code: IL
+  output:
+    il_ctc: 0
+
+- name: SB3567 keeps the Illinois CTC refundable when EITC is zero
+  period: 2025
+  absolute_error_margin: 0.01
+  reforms: policyengine_us.reforms.states.il.sb3567.il_sb3567
+  input:
+    gov.contrib.states.il.sb3567.in_effect: true
+    people:
+      filer:
+        age: 36
+      child:
+        age: 5
+        ctc_qualifying_child: true
+        is_tax_unit_dependent: true
+    tax_units:
+      tax_unit:
+        members: [filer, child]
+        adjusted_gross_income: 10_000
+        il_eitc: 0
+        il_income_tax_before_non_refundable_credits: 0
+        il_property_tax_credit: 0
+        il_k12_education_expense_credit: 0
+        il_pass_through_withholding: 0
+        il_pass_through_entity_tax_credit: 0
+        il_use_tax: 0
+    households:
+      household:
+        members: [filer, child]
+        state_code: IL
+  # AGI below 1-child phase-in threshold so boost applies; il_ctc stays
+  # refundable per existing 35 ILCS 5/244(b), so it flows through to
+  # il_refundable_credits even with no tax liability.
+  output:
+    il_ctc: 346.24
+    il_refundable_credits: 346.24
+    il_income_tax: -346.24
+
+- name: Non-Illinois filers do not receive the reform CTC
+  period: 2025
+  absolute_error_margin: 0.01
+  reforms: policyengine_us.reforms.states.il.sb3567.il_sb3567
+  input:
+    gov.contrib.states.il.sb3567.in_effect: true
+    people:
+      filer:
+        age: 30
+      child:
+        age: 8
+        ctc_qualifying_child: true
+        is_tax_unit_dependent: true
+    tax_units:
+      tax_unit:
+        members: [filer, child]
+        adjusted_gross_income: 12_000
+        il_eitc: 200
+    households:
+      household:
+        members: [filer, child]
+        state_code: CA
+  output:
+    il_ctc: 0
+
+- name: SB3567 boosts a two-child phase-in filer to the two-child maximum
+  period: 2025
+  absolute_error_margin: 0.01
+  reforms: policyengine_us.reforms.states.il.sb3567.il_sb3567
+  input:
+    gov.contrib.states.il.sb3567.in_effect: true
+    people:
+      filer:
+        age: 31
+      child1:
+        age: 7
+        ctc_qualifying_child: true
+        is_tax_unit_dependent: true
+      child2:
+        age: 5
+        ctc_qualifying_child: true
+        is_tax_unit_dependent: true
+    tax_units:
+      tax_unit:
+        members: [filer, child1, child2]
+        adjusted_gross_income: 14_000
+        il_eitc: 250
+    households:
+      household:
+        members: [filer, child1, child2]
+        state_code: IL
+  # 2025 federal EITC max for 2 children = 7,152; IL match = 0.20; CTC rate = 0.4
+  # Boosted credit = 7,152 * 0.20 * 0.4 = 572.16
+  output:
+    il_ctc: 572.16
+
+- name: SB3567 applies the boost at the two-child phase-in threshold
+  period: 2025
+  absolute_error_margin: 0.01
+  reforms: policyengine_us.reforms.states.il.sb3567.il_sb3567
+  input:
+    gov.contrib.states.il.sb3567.in_effect: true
+    people:
+      filer:
+        age: 32
+      child1:
+        age: 6
+        ctc_qualifying_child: true
+        is_tax_unit_dependent: true
+      child2:
+        age: 4
+        ctc_qualifying_child: true
+        is_tax_unit_dependent: true
+    tax_units:
+      tax_unit:
+        members: [filer, child1, child2]
+        # Phase-in threshold for 2 children = 7,152 / 0.40 = 17,880
+        adjusted_gross_income: 17_880
+        il_eitc: 1_430.4
+    households:
+      household:
+        members: [filer, child1, child2]
+        state_code: IL
+  # AGI <= threshold so boost applies; max credit = 572.16
+  output:
+    il_ctc: 572.16