Apply District of Columbia, Georgia and Idaho rules for a filer who can be claimed as a dependent

changelog.d/claimable-filer-dc-ga-id.fixed.md

@@ -0,0 +1 @@
+Apply District of Columbia, Georgia and Idaho rules for a filer who can be claimed as a dependent: DC's property tax credit claimant, childless EITC, child care and child tax credit children; Georgia's dependent exemption, low income credit and 2023 surplus refund; Idaho's food tax credit, household and dependent care deduction and 2022 rebate. Exclude nonqualifying child-only daycare from Idaho's care deduction even when a disabled adult qualifies for care.

policyengine_us/parameters/gov/states/dc/tax/income/credits/ptc/dependent_claimant_min_age.yaml

@@ -0,0 +1,10 @@
+description: The District of Columbia allows a person who was a dependent under an income tax law to claim the property tax credit only at or above this age.
+values:
+  2021-01-01: 65
+metadata:
+  unit: year
+  label: DC property tax credit minimum age for a dependent claimant
+  period: year
+  reference:
+    - title: Code of the District of Columbia § 47–1806.06 (k)
+      href: https://code.dccouncil.gov/us/dc/council/code/sections/47-1806.06

policyengine_us/reforms/dc_kccatc.py

@@ -56,7 +56,15 @@ def formula(tax_unit, period, parameters):
                 income_eligible = taxinc <= p.kccatc.income_limit[filing_status]
                 # determine count of KCCATC age eligible children
                 person = tax_unit.members
-                is_dependent = person("is_tax_unit_dependent", period)
+                # As in the baseline formula: no dependents on a return whose
+                # filer (or, if joint, either spouse) can be claimed.
+                filer_is_dependent = person.tax_unit(
+                    "head_or_spouse_is_dependent_elsewhere_without_filing_exception",
+                    period,
+                )
+                is_dependent = (
+                    person("is_tax_unit_dependent", period) & ~filer_is_dependent
+                )
                 age = person("age", period)
                 kccatc_age_eligible = is_dependent & (age <= p.kccatc.max_age)
                 kccatc_eligible_count = tax_unit.sum(kccatc_age_eligible)

policyengine_us/reforms/states/dc/property_tax/dc_property_tax_reform.py

@@ -22,12 +22,15 @@ def formula(tax_unit, period, parameters):
             # Income based eligibility criteria does not apply when the credit
             # is phased out.
             eligible = tax_unit("dc_ptc_eligible", period)
+            # The reform keeps D.C. Code 47-1806.06(k): no credit through a
+            # claimant who was a dependent, unless 65 or older.
+            has_claimant = tax_unit("dc_ptc_has_eligible_claimant", period)
             if p.phase_out.applies:
                 income_limit = tax_unit("dc_ptc_income_limit", period)
                 income = tax_unit("adjusted_gross_income", period)
                 income_excess = max_(0, income - income_limit)
-                return max_(0, amount - p.phase_out.rate * income_excess)
-            return amount * eligible
+                return max_(0, amount - p.phase_out.rate * income_excess) * has_claimant
+            return amount * eligible * has_claimant
 
     class dc_ptc_eligible(Variable):
         value_type = bool

policyengine_us/reforms/states/ga/dependent_exemption/ga_dependent_exemption_reform.py

@@ -15,7 +15,13 @@ def formula(tax_unit, period, parameters):
 
             person = tax_unit.members
             age = person("age", period)
-            is_dependent = person("is_tax_unit_dependent", period)
+            # A return on which the filer (or, if joint, either spouse) can be
+            # claimed as a dependent has no dependents (IRC 152(b)(1)), as in
+            # the baseline formula.
+            filer_is_dependent = person.tax_unit(
+                "head_or_spouse_is_dependent_elsewhere_without_filing_exception", period
+            )
+            is_dependent = person("is_tax_unit_dependent", period) & ~filer_is_dependent
 
             # Apply age limit if in effect.
             if p.age_limit.in_effect:

policyengine_us/tests/core/test_claimable_filer_dc_ga_id_invariants.py

@@ -0,0 +1,195 @@
+"""District of Columbia, Georgia and Idaho rules for a filer who can be claimed
+as a dependent.
+
+A return on which the filer, or on a joint return either spouse, can be claimed
+as a dependent outside the filing exception has no dependents (IRC 152(b)(1)).
+DC's property tax credit needs a claimant who was not a dependent or is 65 or
+older; Georgia's low income credit and 2023 surplus refund need one filer who
+qualifies; Idaho's food tax credit leaves out each filer who can be claimed.
+
+For couples drawn by Hypothesis and a seeded population in these states,
+claimability, actual claims and the filing exception vary independently,
+subject to an actual claim requiring claimability and excluding the exception:
+
+1. Swap invariance: each output is the same under either head/spouse
+   labelling.
+2. Monotonicity: marking another filer as claimed, with fallback claimability
+   and no filing exception, never raises the outputs in MONOTONE (amounts not
+   capped by a tax liability that the claim can raise).
+3. Identities: a return with a claimable filer outside the filing exception has
+   no DC keep child care affordable credit or child tax credit and its Idaho
+   food tax credit is at most one filer's amount; a return on which every
+   filer can be claimed has no Georgia low income credit.
+
+Hypothesis batches check 1 and 3; the seeded population checks 1, 2 and 3.
+"""
+
+import numpy as np
+import pytest
+from hypothesis import HealthCheck, given, settings
+from hypothesis import strategies as st
+
+from policyengine_us.tests.core.test_claimable_filer_federal_invariants import (
+    check_monotone,
+    check_swap,
+)
+from policyengine_us.tests.core.test_dependent_elsewhere_head_spouse_swap_invariance import (
+    CLAIM_PATTERNS,
+    _calc,
+    _crafted_cases,
+    _seeded_couples,
+    adults,
+    dependents,
+)
+
+STATES = ["DC", "GA", "ID"]
+YEARS = [2021, 2023, 2025, 2026]
+MONOTONE = [
+    "dc_ptc",
+    "dc_eitc",
+    "dc_kccatc",
+    "dc_ctc",
+    "ga_exemptions",
+    "ga_low_income_credit_potential",
+    "ga_ctc_potential",
+    "id_grocery_credit",
+    "id_household_and_dependent_care_expense_deduction",
+]
+OUTPUTS = MONOTONE + ["ga_surplus_tax_rebate", "id_2022_rebate"]
+
+
+@st.composite
+def couples(draw):
+    claimable = draw(st.sampled_from(CLAIM_PATTERNS))
+    claimed = tuple(can_claim and draw(st.booleans()) for can_claim in claimable)
+    return {
+        "state": draw(st.sampled_from(STATES)),
+        "adults": [draw(adults()), draw(adults())],
+        "dependents": draw(st.lists(dependents(), max_size=2)),
+        "claimed": claimed,
+        "claimable": claimable,
+        "exception": tuple(
+            not is_claimed and draw(st.booleans()) for is_claimed in claimed
+        ),
+    }
+
+
+def _identities(sim, year):
+    blocked_filer = (
+        _calc(
+            sim, "head_or_spouse_is_dependent_elsewhere_without_filing_exception", year
+        )
+        > 0
+    )
+    for name in ("dc_kccatc", "dc_ctc"):
+        assert not _calc(sim, name, year)[blocked_filer].any(), (
+            f"{name} in {year} is positive on a return with a claimable filer "
+            "outside the filing exception"
+        )
+    # Georgia's low income credit needs one filer who cannot be claimed.
+    every_filer = _calc(sim, "every_filer_is_dependent_elsewhere", year) > 0
+    assert not _calc(sim, "ga_low_income_credit_potential", year)[every_filer].any()
+    # Outside the filing exception, at most the independent filer keeps a
+    # food tax credit; no dependent child qualifies.
+    one_filer = _one_filer_food_amount(sim, year)
+    grocery = _calc(sim, "id_grocery_credit", year)
+    assert (grocery[blocked_filer] <= one_filer + 0.01).all()
+
+
+def _one_filer_food_amount(sim, year):
+    p = sim.tax_benefit_system.parameters(f"{year}-01-01").gov.states.id.tax.income
+    amount = p.credits.grocery.base.amount
+    if p.credits.grocery.aged.in_effect:
+        amount += p.credits.grocery.aged.amount
+    return amount
+
+
+def _with_independent_claim_inputs(units):
+    rng = np.random.default_rng(20261018)
+    result = []
+    for unit in units:
+        claimable = CLAIM_PATTERNS[int(rng.integers(len(CLAIM_PATTERNS)))]
+        claimed = tuple(can_claim and bool(rng.integers(2)) for can_claim in claimable)
+        exception = tuple(
+            not is_claimed and bool(rng.integers(2)) for is_claimed in claimed
+        )
+        result.append(
+            {
+                **unit,
+                "claimable": claimable,
+                "claimed": claimed,
+                "exception": exception,
+            }
+        )
+    return result
+
+
+@pytest.mark.parametrize(
+    "year,state,expected",
+    [
+        (2025, "ID", {"id_grocery_credit": 310}),
+        (2026, "DC", {"dc_kccatc": 1_000, "dc_ctc": 1_000}),
+    ],
+)
+def test_dc_id_filing_exception_restores_children_under_both_labels(
+    year, state, expected
+):
+    # The claimable adult keeps the exception and the independent spouse and
+    # child keep their credits when either adult is labelled head. Idaho still
+    # excludes the claimable adult's own $155 food tax credit.
+    units = [
+        {
+            "state": state,
+            "adults": [{"age": 26, "employment_income": 2_000}, {"age": 30}],
+            "dependents": [{"age": 2, "pre_subsidy_childcare_expenses": 1_000}],
+            "claimed": (False, False),
+            "claimable": (True, False),
+            "exception": (True, False),
+        }
+    ]
+    if state == "ID":
+        # Isolate the dependency rule from SNAP and other month exclusions.
+        for person in units[0]["adults"] + units[0]["dependents"]:
+            person["id_grocery_credit_qualified_months"] = 12
+
+    def exception_identities(sim, year):
+        for name, amount in expected.items():
+            np.testing.assert_allclose(_calc(sim, name, year), [amount, amount])
+        _identities(sim, year)
+
+    check_swap(units, year, OUTPUTS, exception_identities)
+
+
+@settings(
+    max_examples=2,
+    deadline=None,
+    derandomize=True,
+    suppress_health_check=[HealthCheck.too_slow, HealthCheck.data_too_large],
+)
+@given(st.sampled_from(YEARS), st.lists(couples(), min_size=6, max_size=12))
+def test_dc_ga_id_claimable_filer_rules_are_label_free(year, units):
+    check_swap(units, year, OUTPUTS, _identities)
+
+
+@pytest.mark.parametrize("year", YEARS)
+def test_dc_ga_id_claimable_filer_rules_seeded_population(year):
+    seeded = _seeded_couples(STATES, per_state=3)
+    crafted = _crafted_cases(STATES)
+    # Core fills omitted people with input defaults once any person supplies
+    # claimability, so express the crafted cases' legacy values explicitly in
+    # the swap simulation. The monotonicity simulation retains their fallback.
+    explicit_crafted = [
+        {**unit, "claimable": unit["claimed"], "exception": (False, False)}
+        for unit in crafted
+    ]
+    check_swap(
+        _with_independent_claim_inputs(seeded) + explicit_crafted,
+        year,
+        OUTPUTS,
+        _identities,
+    )
+    # The shared monotonicity helper toggles actual claims while keeping any
+    # explicit claimability and exception inputs fixed. Retain the legacy
+    # population here so every variant is valid and claimability changes with
+    # the actual claim; the swap population independently exercises all inputs.
+    check_monotone(seeded + crafted, year, MONOTONE, _identities)

policyengine_us/tests/policy/baseline/gov/states/dc/tax/income/ctc/dc_ctc_eligible_child.yaml

@@ -33,3 +33,140 @@
     state_code: DC
   output:
     dc_ctc_eligible_child: false
+
+
+- name: 2026 single filer who can be claimed as a dependent, no DC child tax credit child
+  period: 2026
+  input:
+    people:
+      filer:
+        age: 30
+        employment_income: 10_000
+        is_tax_unit_head: true
+        is_tax_unit_spouse: false
+        claimed_as_dependent_on_another_return: true
+      child:
+        age: 3
+    tax_units:
+      tax_unit:
+        members: [filer, child]
+    households:
+      household:
+        members: [filer, child]
+        state_code: DC
+  output:
+    # 47-1806.17(a): a child for whom the taxpayer is allowed a
+    # deduction under IRC 151; IRC 152(b)(1).
+    dc_ctc_eligible_child: [false, false]
+
+- name: 2026 joint return with one spouse who can be claimed as a dependent, no DC child tax credit child (the claimable spouse is the head)
+  period: 2026
+  input:
+    people:
+      person_a:
+        age: 30
+        employment_income: 5_000
+        is_tax_unit_head: true
+        is_tax_unit_spouse: false
+        claimed_as_dependent_on_another_return: true
+      person_b:
+        age: 30
+        employment_income: 5_000
+        is_tax_unit_head: false
+        is_tax_unit_spouse: true
+      child:
+        age: 3
+    tax_units:
+      tax_unit:
+        members: [person_a, person_b, child]
+        filing_status: JOINT
+    households:
+      household:
+        members: [person_a, person_b, child]
+        state_code: DC
+  output:
+    dc_ctc_eligible_child: [false, false, false]
+
+- name: 2026 joint return with one spouse who can be claimed as a dependent, no DC child tax credit child (the claimable spouse is the spouse)
+  period: 2026
+  input:
+    people:
+      person_b:
+        age: 30
+        employment_income: 5_000
+        is_tax_unit_head: true
+        is_tax_unit_spouse: false
+      person_a:
+        age: 30
+        employment_income: 5_000
+        is_tax_unit_head: false
+        is_tax_unit_spouse: true
+        claimed_as_dependent_on_another_return: true
+      child:
+        age: 3
+    tax_units:
+      tax_unit:
+        members: [person_b, person_a, child]
+        filing_status: JOINT
+    households:
+      household:
+        members: [person_b, person_a, child]
+        state_code: DC
+  output:
+    dc_ctc_eligible_child: [false, false, false]
+
+- name: 2026 joint return with both spouses claimable as dependents, no DC child tax credit child
+  period: 2026
+  input:
+    people:
+      person_a:
+        age: 30
+        employment_income: 5_000
+        is_tax_unit_head: true
+        is_tax_unit_spouse: false
+        claimed_as_dependent_on_another_return: true
+      person_b:
+        age: 30
+        employment_income: 5_000
+        is_tax_unit_head: false
+        is_tax_unit_spouse: true
+        claimed_as_dependent_on_another_return: true
+      child:
+        age: 3
+    tax_units:
+      tax_unit:
+        members: [person_a, person_b, child]
+        filing_status: JOINT
+    households:
+      household:
+        members: [person_a, person_b, child]
+        state_code: DC
+  output:
+    dc_ctc_eligible_child: [false, false, false]
+
+- name: 2026 joint return with neither spouse claimable, no DC child tax credit child
+  period: 2026
+  input:
+    people:
+      person_a:
+        age: 30
+        employment_income: 5_000
+        is_tax_unit_head: true
+        is_tax_unit_spouse: false
+      person_b:
+        age: 30
+        employment_income: 5_000
+        is_tax_unit_head: false
+        is_tax_unit_spouse: true
+      child:
+        age: 3
+    tax_units:
+      tax_unit:
+        members: [person_a, person_b, child]
+        filing_status: JOINT
+    households:
+      household:
+        members: [person_a, person_b, child]
+        state_code: DC
+  output:
+    dc_ctc_eligible_child: [false, false, true]