Fix miscellaneous accuracy issues (CA AMT, AZ PTC, LA FITAP, NV TANF)

changelog.d/misc-accuracy.fixed.md

@@ -0,0 +1,4 @@
+- California AMT no longer double-adds disallowed itemized deductions; Schedule P (540) Part I now adds regular taxable income plus specific AMT adjustments minus the restored itemized deductions limitation (line 18), instead of adding the full pre-limitation itemized deductions.
+- Arizona property tax credit now selects the higher Table 2 credit schedule for any claimant living with one or more other persons (including a non-spouse cohabitant), matching ARS 43-1072(A)(3)(b), rather than only for married couples and cohabitating spouses.
+- Louisiana FITAP now rounds the grant deficit down to a whole dollar and pays no grant when the rounded deficit is below $10, per DCFS manual B-641-1-FITAP.
+- Nevada TANF now rounds the monthly benefit down to a whole dollar and issues no regular benefit below $10, per Eligibility and Payments Manual A-660.12.

policyengine_us/parameters/gov/states/la/dcfs/fitap/minimum_payment.yaml

@@ -0,0 +1,12 @@
+description: Louisiana pays no Family Independence Temporary Assistance Program grant when the rounded-down deficit is below this amount, though the assistance unit remains FITAP eligible.
+values:
+  2023-01-01: 10
+metadata:
+  unit: currency-USD
+  period: month
+  label: Louisiana FITAP minimum payment
+  reference:
+    - title: Louisiana DCFS Economic Stability Manual B-640-FITAP Income Limits, B-641-1-FITAP (Determination of Eligibility and Grant Amount)
+      href: https://public.powerdms.com/LADCFS/documents/398921
+    - title: Louisiana Administrative Code Title 67, Part III, Section 1229
+      href: https://www.law.cornell.edu/regulations/louisiana/La-Admin-Code-tit-67-SS-III-1229

policyengine_us/parameters/gov/states/nv/dwss/tanf/minimum_payment.yaml

@@ -0,0 +1,13 @@
+description: Nevada pays no regular monthly TANF benefit below this amount; benefits under this floor are issued only as supplemental payments or after an overpayment recoupment.
+# The $10 minimum issuance rule is a longstanding Nevada TANF benefit-issuance
+# standard; it is dated to the start of the modeled NV TANF payment standard
+# (2007) and sourced to the current Eligibility and Payments Manual A-660.12.
+values:
+  2007-07-01: 10
+metadata:
+  unit: currency-USD
+  period: month
+  label: Nevada TANF minimum payment
+  reference:
+    - title: Nevada DWSS Eligibility and Payments Manual, A-660.12 TANF Benefit Amount/SNAP Allotment
+      href: https://dwss.nv.gov/siteassets/dwss.nv.gov/ep-manual-section-a/chapter-a-600-budgeting-ada-8.2025.pdf#page=38

policyengine_us/tests/policy/baseline/gov/states/az/tax/income/credits/az_property_tax_credit.yaml

@@ -80,3 +80,34 @@
     households: {household: {members: [head, spouse], state_code: AZ}}
   output:
     az_property_tax_credit: 323
+
+# ARS 43-1072(A)(3)(b): a single claimant who "lived with a spouse or one or
+# more persons" uses the Table 2 (cohabitating) schedule. An elderly single
+# filer living with a non-dependent adult child lives with another person.
+- name: AZ property tax credit uses Table 2 for a single claimant living with an adult child
+  period: 2025
+  input:
+    people:
+      head: {age: 75, taxable_interest_income: 3_637.87, rent: 9_059.32}
+      # Adult child living in the same household (not a tax dependent).
+      child: {age: 40, is_tax_unit_dependent: false}
+    tax_units:
+      claimant: {members: [head]}
+      child_unit: {members: [child]}
+    households: {household: {members: [head, child], state_code: AZ}}
+  output:
+    # At $3,637.87 income the Table 2 (cohabitating) credit is $323, whereas the
+    # Table 1 (living-alone) schedule would give only $78. The adult child's
+    # own tax unit is not credit-eligible (under age 65, no SSI).
+    az_property_tax_credit: [323, 0]
+
+# A truly solitary elderly filer at the same income uses the Table 1 schedule.
+- name: AZ property tax credit uses Table 1 for a single claimant living alone
+  period: 2025
+  input:
+    people:
+      head: {age: 75, taxable_interest_income: 3_637.87, rent: 9_059.32}
+    tax_units: {tax_unit: {members: [head]}}
+    households: {household: {members: [head], state_code: AZ}}
+  output:
+    az_property_tax_credit: 78

policyengine_us/tests/policy/baseline/gov/states/ca/tax/income/alternative_minimum_tax/amti/ca_itemized_deductions_limitation.yaml

@@ -0,0 +1,22 @@
+# Schedule P (540) Part I, line 18: the amount of itemized deductions
+# disallowed for regular tax under the California high-AGI limitation, which
+# is restored for AMT.
+# https://www.ftb.ca.gov/forms/2024/2024-540-p.pdf#page=1
+
+- name: No limitation when pre and post limitation deductions are equal
+  period: 2026
+  input:
+    state_code: CA
+    ca_itemized_deductions_pre_limitation: 45_000
+    ca_itemized_deductions: 45_000
+  output:
+    ca_itemized_deductions_limitation: 0
+
+- name: Limitation equals the reduction in itemized deductions
+  period: 2026
+  input:
+    state_code: CA
+    ca_itemized_deductions_pre_limitation: 58_000
+    ca_itemized_deductions: 49_132.18
+  output:
+    ca_itemized_deductions_limitation: 8_867.82

policyengine_us/tests/policy/baseline/gov/states/ca/tax/income/alternative_minimum_tax/amti/ca_pre_exemption_amti.yaml

@@ -0,0 +1,64 @@
+# Schedule P (540) Part I, line 19 / line 21.
+# https://www.ftb.ca.gov/forms/2024/2024-540-p.pdf#page=1
+# AMTI = regular taxable income (line 15) + total adjustments/preferences
+# (line 14) - restored itemized deductions limitation (line 18).
+# Disallowed itemized deductions (property taxes, medical) are added back
+# once via ca_amti_adjustments; the full pre-limitation itemized deductions
+# must NOT be added again (issue #8742).
+
+- name: Property taxes are not double-added; AMTI equals AGI when no limitation applies
+  period: 2026
+  input:
+    state_code: CA
+    ca_agi: 199_500
+    ca_taxable_income: 154_500
+    # Single filer, $45,000 real property tax deducted (below the CA high-AGI
+    # itemized-deduction limitation threshold, so pre = post limitation).
+    ca_amti_adjustments: 45_000
+    ca_itemized_deductions_pre_limitation: 45_000
+    ca_itemized_deductions: 45_000
+  output:
+    # 154_500 + 45_000 - 0 = 199_500 (= AGI), flat regardless of property tax.
+    ca_pre_exemption_amti: 199_500
+
+- name: Higher property taxes keep AMTI flat at AGI (issue 8742 reproduction)
+  period: 2026
+  input:
+    state_code: CA
+    ca_agi: 199_500
+    ca_taxable_income: 99_500
+    ca_amti_adjustments: 100_000
+    ca_itemized_deductions_pre_limitation: 100_000
+    ca_itemized_deductions: 100_000
+  output:
+    # 99_500 + 100_000 - 0 = 199_500; property tax does not inflate AMTI.
+    ca_pre_exemption_amti: 199_500
+
+- name: High-AGI itemized-deduction limitation is restored for AMT (line 18)
+  period: 2026
+  input:
+    state_code: CA
+    ca_agi: 400_000
+    # Regular taxable income reflects post-limitation deductions.
+    ca_taxable_income: 350_867.81
+    # Only real property taxes ($10,000) are disallowed for AMT.
+    ca_amti_adjustments: 10_000
+    ca_itemized_deductions_pre_limitation: 58_000
+    ca_itemized_deductions: 49_132.18
+  output:
+    # 350_867.81 + 10_000 - (58_000 - 49_132.18) = 352_000.
+    ca_pre_exemption_amti: 352_000
+
+- name: Non-itemizer AMTI equals AGI (standard deduction added back on line 1)
+  period: 2026
+  input:
+    state_code: CA
+    ca_agi: 80_000
+    # Taxable income = AGI - standard deduction ($5,706 single, 2026).
+    ca_taxable_income: 74_294
+    # ca_amti_adjustments returns the standard deduction for non-itemizers.
+    ca_amti_adjustments: 5_706
+    ca_itemized_deductions_pre_limitation: 0
+    ca_itemized_deductions: 0
+  output:
+    ca_pre_exemption_amti: 80_000

policyengine_us/tests/policy/baseline/gov/states/la/dcfs/fitap/la_fitap.yaml

@@ -28,3 +28,47 @@
     la_fitap_countable_income: 0
   output:
     la_fitap: 0
+
+# DCFS manual B-641-1-FITAP: the deficit is rounded down; if it is less than
+# $10 the unit is eligible but no grant is paid.
+- name: Deficit under $10 pays no grant (issue 8770 example 1)
+  # $244 flat grant - $235.50 income = $8.50 deficit < $10, so no grant.
+  period: 2024-01
+  input:
+    state_code: LA
+    la_fitap_eligible: true
+    la_fitap_flat_grant: 244
+    la_fitap_countable_income: 235.50
+  output:
+    la_fitap: 0
+
+- name: Deficit of $10 or more is rounded down to the grant (issue 8770 example 2)
+  # $484 flat grant - $450.75 income = $33.25 deficit, rounded down to $33.
+  period: 2024-01
+  input:
+    state_code: LA
+    la_fitap_eligible: true
+    la_fitap_flat_grant: 484
+    la_fitap_countable_income: 450.75
+  output:
+    la_fitap: 33
+
+- name: Deficit of exactly $10 pays $10
+  period: 2024-01
+  input:
+    state_code: LA
+    la_fitap_eligible: true
+    la_fitap_flat_grant: 244
+    la_fitap_countable_income: 234
+  output:
+    la_fitap: 10
+
+- name: Deficit of $9.99 pays no grant
+  period: 2024-01
+  input:
+    state_code: LA
+    la_fitap_eligible: true
+    la_fitap_flat_grant: 244
+    la_fitap_countable_income: 234.01
+  output:
+    la_fitap: 0

policyengine_us/tests/policy/baseline/gov/states/nv/dwss/tanf/nv_tanf.yaml

@@ -42,3 +42,50 @@
     nv_tanf_countable_income: 0
   output:
     nv_tanf: 0
+
+# E&P Manual A-660.12: "A benefit is always a whole dollar amount. Round all
+# amounts down to the nearest dollar."
+- name: Benefit is rounded down to a whole dollar
+  period: 2025-01
+  input:
+    state_code: NV
+    nv_tanf_eligible: true
+    nv_tanf_payment_standard: 386
+    nv_tanf_countable_income: 100.75
+  output:
+    # $386 - $100.75 = $285.25, rounded down to $285.
+    nv_tanf: 285
+
+# A-660.12: "The minimum benefit amount is $10." Regular benefits below $10
+# are not issued.
+- name: Benefit below the $10 minimum is not issued
+  period: 2025-01
+  input:
+    state_code: NV
+    nv_tanf_eligible: true
+    nv_tanf_payment_standard: 386
+    nv_tanf_countable_income: 379
+  output:
+    # $386 - $379 = $7 < $10, so no benefit is issued.
+    nv_tanf: 0
+
+- name: Benefit of exactly $10 is issued
+  period: 2025-01
+  input:
+    state_code: NV
+    nv_tanf_eligible: true
+    nv_tanf_payment_standard: 386
+    nv_tanf_countable_income: 376
+  output:
+    nv_tanf: 10
+
+- name: Deficit that rounds below $10 is not issued
+  period: 2025-01
+  input:
+    state_code: NV
+    nv_tanf_eligible: true
+    nv_tanf_payment_standard: 386
+    nv_tanf_countable_income: 376.50
+  output:
+    # $386 - $376.50 = $9.50, rounds down to $9 < $10, so no benefit.
+    nv_tanf: 0

policyengine_us/variables/gov/states/az/tax/income/credits/property_tax_credit/az_property_tax_credit.py

@@ -15,15 +15,21 @@ def formula(tax_unit, period, parameters):
         income = tax_unit("az_property_tax_credit_income", period)
 
         # ARS 43-1072(A)(3): a claimant who "lived with a spouse or one or
-        # more persons" uses the Table 2 (cohabitating) schedule. A married
-        # couple filing jointly lives together, so treat them as cohabitating
-        # regardless of the (default-False) cohabitating_spouses input.
-        cohabitating = tax_unit("cohabitating_spouses", period) | tax_unit(
-            "tax_unit_married", period
+        # more persons" uses the Table 2 (B)(2) schedule, while a claimant who
+        # "did not live with a spouse or any other persons" uses the Table 1
+        # (B)(1) schedule. Any co-resident (spouse, adult child, sibling,
+        # roommate) triggers Table 2. Use the broadest available signal:
+        # explicit cohabitating-spouses input, a married couple filing jointly,
+        # or a household with more than one person.
+        household_size = tax_unit.household("household_size", period)
+        lives_with_others = (
+            tax_unit("cohabitating_spouses", period)
+            | tax_unit("tax_unit_married", period)
+            | (household_size > 1)
         )
 
         cap = where(
-            cohabitating,
+            lives_with_others,
             p.amount.cohabitating.calc(income),
             p.amount.living_alone.calc(income),
         )

policyengine_us/variables/gov/states/ca/tax/income/alternative_minimum_tax/amti/ca_itemized_deductions_limitation.py

@@ -0,0 +1,22 @@
+from policyengine_us.model_api import *
+
+
+class ca_itemized_deductions_limitation(Variable):
+    value_type = float
+    entity = TaxUnit
+    label = "California itemized deductions limitation restored for AMT"
+    defined_for = StateCode.CA
+    unit = USD
+    definition_period = YEAR
+    reference = "https://www.ftb.ca.gov/forms/2024/2024-540-p.pdf#page=1"
+
+    def formula(tax_unit, period, parameters):
+        # Schedule P (540) Part I, line 18. For regular tax, high-AGI filers
+        # have their itemized deductions reduced (California itemized
+        # deductions limitation). This limitation does not apply for AMT, so
+        # the amount of deductions disallowed for regular tax is restored
+        # (subtracted from AMTI, since it was excluded from regular taxable
+        # income on Form 540 line 19 / Schedule P line 15).
+        pre_limitation = tax_unit("ca_itemized_deductions_pre_limitation", period)
+        post_limitation = tax_unit("ca_itemized_deductions", period)
+        return max_(pre_limitation - post_limitation, 0)

policyengine_us/variables/gov/states/ca/tax/income/alternative_minimum_tax/amti/ca_pre_exemption_amti.py

@@ -8,11 +8,21 @@ class ca_pre_exemption_amti(Variable):
     defined_for = StateCode.CA
     unit = USD
     definition_period = YEAR
-    reference = "https://www.ftb.ca.gov/forms/2022/2022-540-p.pdf"
+    reference = "https://www.ftb.ca.gov/forms/2024/2024-540-p.pdf#page=1"
 
-    # Line 19
+    # Schedule P (540) Part I, line 19: combine regular taxable income
+    # (line 15) with the total AMT adjustments and preferences (line 14) and
+    # subtract the restored itemized deductions limitation (line 18).
+    #
+    # ca_amti_adjustments (line 14) adds back only the specific AMT-disallowed
+    # itemized deductions (property taxes, medical, etc.), so the full
+    # pre-limitation itemized deductions must NOT be added on top; doing so
+    # double-counts disallowed items and adds back deductions (e.g. charity,
+    # acquisition mortgage interest) that AMT still allows.
     adds = [
         "ca_amti_adjustments",
         "ca_taxable_income",
-        "ca_itemized_deductions_pre_limitation",
+    ]
+    subtracts = [
+        "ca_itemized_deductions_limitation",
     ]

policyengine_us/variables/gov/states/la/dcfs/fitap/la_fitap.py

@@ -11,9 +11,15 @@ class la_fitap(Variable):
     defined_for = "la_fitap_eligible"
 
     def formula(spm_unit, period, parameters):
+        p = parameters(period).gov.states.la.dcfs.fitap
         flat_grant = spm_unit("la_fitap_flat_grant", period)
         countable_income = spm_unit("la_fitap_countable_income", period)
 
-        # Benefit = flat grant minus countable income
-        benefit = max_(flat_grant - countable_income, 0)
-        return min_(benefit, flat_grant)
+        # DCFS manual B-641-1-FITAP: the deficit between the flat grant and
+        # countable income, rounded down. If the rounded deficit is $10 or
+        # more it is the grant amount; if it is less than $10 the unit is
+        # FITAP-eligible but no grant is paid.
+        deficit = max_(flat_grant - countable_income, 0)
+        rounded_deficit = np.floor(deficit)
+        grant = min_(rounded_deficit, flat_grant)
+        return where(grant >= p.minimum_payment, grant, 0)

policyengine_us/variables/gov/states/nv/dwss/tanf/nv_tanf.py

@@ -7,14 +7,23 @@ class nv_tanf(Variable):
     label = "Nevada Temporary Assistance for Needy Families (TANF)"
     unit = USD
     definition_period = MONTH
-    reference = "https://dss.nv.gov/TANF/Financial_Help/"
+    reference = "https://dwss.nv.gov/siteassets/dwss.nv.gov/ep-manual-section-a/chapter-a-600-budgeting-ada-8.2025.pdf#page=38"
     defined_for = "nv_tanf_eligible"
 
     def formula(spm_unit, period, parameters):
+        p = parameters(period).gov.states.nv.dwss.tanf
         payment_standard = spm_unit("nv_tanf_payment_standard", period)
         countable_income = spm_unit("nv_tanf_countable_income", period)
         # Benefit is payment standard minus countable income
         benefit = max_(payment_standard - countable_income, 0)
         # Cap benefit at payment standard to prevent negative income
         # from inflating benefits above the maximum.
-        return min_(benefit, payment_standard)
+        benefit = min_(benefit, payment_standard)
+        # E&P Manual A-660.12: "A benefit is always a whole dollar amount.
+        # Round all amounts down to the nearest dollar."
+        benefit = np.floor(benefit)
+        # A-660.12: "The minimum benefit amount is $10." Regular monthly
+        # benefits below $10 are not issued (only supplemental payments and
+        # post-overpayment-recoupment payments, which PolicyEngine does not
+        # model, may fall below $10).
+        return where(benefit >= p.minimum_payment, benefit, 0)