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 +1,14 @@
+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://www.ilga.gov/documents/legislation/104/SB/PDF/10400SB3567lv.pdf#page=2
+    - title: 35 ILCS 5/244 Child tax credit
+      href: https://www.ilga.gov/legislation/ilcs/fulltext.asp?DocName=003500050K244

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 +1,131 @@
+from policyengine_core.periods import instant, period as period_
+from policyengine_us.model_api import *
+from policyengine_us.variables.gov.states.tax.income.non_refundable_credit_cap import (
+    applied_state_non_refundable_credit,
+)
+
+
+def create_il_sb3567() -> Reform:
+    class il_ctc_potential(Variable):
+        value_type = float
+        entity = TaxUnit
+        label = "Illinois Child Tax Credit before non-refundable cap"
+        unit = USD
+        definition_period = YEAR
+        reference = (
+            "https://www.ilga.gov/documents/legislation/104/SB/PDF/10400SB3567lv.pdf#page=2",
+            "https://www.ilga.gov/legislation/ilcs/fulltext.asp?DocName=003500050K244",
+            "https://www.law.cornell.edu/uscode/text/26/152",
+        )
+        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
+
+            if period.start.year < 2025:
+                return eligible_child_present * actual_credit
+
+            # The bill's "income threshold to qualify for the maximum federal
+            # EITC" is the end of the phase-in range (start of the plateau).
+            federal_maximum = tax_unit("eitc_maximum", period)
+            phase_in_rate = tax_unit("eitc_phase_in_rate", period)
+            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 il_ctc(Variable):
+        value_type = float
+        entity = TaxUnit
+        label = "Illinois Child Tax Credit"
+        unit = USD
+        definition_period = YEAR
+        reference = (
+            "https://www.ilga.gov/documents/legislation/104/SB/PDF/10400SB3567lv.pdf#page=2",
+            "https://www.ilga.gov/legislation/ilcs/fulltext.asp?DocName=003500050K244",
+        )
+        defined_for = StateCode.IL
+
+        def formula(tax_unit, period, parameters):
+            if period.start.year < 2025:
+                return tax_unit("il_ctc_potential", period)
+
+            ordered_credits = parameters(
+                period
+            ).gov.states.il.tax.income.credits.non_refundable
+            return applied_state_non_refundable_credit(
+                tax_unit,
+                period,
+                ordered_credits,
+                "il_income_tax_before_non_refundable_credits",
+                "il_ctc",
+                "il_ctc_potential",
+            )
+
+    def modify_parameters(parameters: ParameterNode) -> ParameterNode:
+        refundable = parameters.gov.states.il.tax.income.credits.refundable
+        refundable_credits = list(refundable(instant("2025-01-01")))
+        if "il_ctc" in refundable_credits:
+            refundable_credits.remove("il_ctc")
+        refundable.update(
+            start=instant("2025-01-01"),
+            stop=instant("2100-12-31"),
+            value=refundable_credits,
+        )
+
+        non_refundable = parameters.gov.states.il.tax.income.credits.non_refundable
+        non_refundable_credits = list(non_refundable(instant("2025-01-01")))
+        if "il_ctc" not in non_refundable_credits:
+            non_refundable_credits.append("il_ctc")
+        non_refundable.update(
+            start=instant("2025-01-01"),
+            stop=instant("2100-12-31"),
+            value=non_refundable_credits,
+        )
+        return parameters
+
+    class reform(Reform):
+        def apply(self):
+            self.add_variable(il_ctc_potential)
+            self.update_variable(il_ctc)
+            self.modify_parameters(modify_parameters)
+
+    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)