Guard county-keyed lookups in VT renter credit, MN CCAP, WI Shares and MD CCS

changelog.d/fix-county-lookup-guards.fixed.md

@@ -0,0 +1 @@
+Stop the Vermont renter credit, Minnesota CCAP provider rate, Wisconsin Shares maximum rates and Maryland CCS payment rate from crashing simulations that include households outside the state, households with an unknown county, or (Vermont) tax units larger than eight people, which now use the eight-person income limits and fair market rent as the Department of Taxes calculator does.

policyengine_us/parameters/gov/states/vt/tax/income/credits/renter/max_household_size.yaml

@@ -0,0 +1,20 @@
+description: Vermont applies the renter credit income limits and fair market rents for this household size to larger households.
+# The income limit and fair market rent tables run through family size 8. The
+# Department of Taxes' renter credit calculators (Calculator sheet, cells
+# G11-G12) look up IF(Household_Size>8,8,Household_Size) in the income limit
+# tables and accept family sizes 1 through 10. Their credit amount lookup (cell
+# G13) caps the size at 4, which the fair market rent table already reflects by
+# repeating the 4-person value through size 8.
+values:
+  2021-01-01: 8
+metadata:
+  unit: person
+  period: year
+  label: Vermont renter credit maximum household size
+  reference:
+    - title: 2025 Renter Credit Website Calculator (Calculator sheet, cells G11-G13)
+      href: https://tax.vermont.gov/sites/tax/files/documents/2025%20Renter%20Credit%20Website%20Calculator.xlsx
+    - title: 2024 Renter Credit Website Calculator (Calculator sheet, cells G11-G13)
+      href: https://tax.vermont.gov/sites/tax/files/documents/2024%20Renter%20Credit%20Website%20Calculator.xlsx
+    - title: 2023 Renter Credit Website Calculator (Calculator sheet, cells G11-G13)
+      href: https://web.archive.org/web/20250526044955/https://tax.vermont.gov/sites/tax/files/documents/2023%20Renter%20Credit%20Website%20Calculator_1.xlsx

policyengine_us/tests/policy/baseline/gov/states/md/msde/ccs/md_ccs_payment_rate.yaml

@@ -247,3 +247,77 @@
     # Negative hours -> 0 units from the bracket -> select default UNIT_1.
     # Region X, Center, REGULAR (age 5), UNIT_3 base $381/week x 1/3 = $127/week
     md_ccs_payment_rate: [0, 127]
+
+- name: Informal provider, unknown-county and out-of-state households in one simulation with a Montgomery County household.
+  # defined_for masks the output but the formula still runs over every
+  # household in the simulation. Before the UNKNOWN guard, the Maryland
+  # household with an UNKNOWN county reached the county-keyed informal rate
+  # table and raised ParameterNotFoundError.
+  period: 2026-01
+  absolute_error_margin: 0.1
+  input:
+    people:
+      person1:
+        age: 30
+        employment_income: 40_000
+        is_tax_unit_head_or_spouse: true
+      person2:
+        age: 3
+        is_tax_unit_dependent: true
+        immigration_status: CITIZEN
+        childcare_hours_per_day: 2
+        md_ccs_provider_type: INFORMAL
+      person3:
+        age: 30
+        employment_income: 40_000
+        is_tax_unit_head_or_spouse: true
+      person4:
+        age: 3
+        is_tax_unit_dependent: true
+        immigration_status: CITIZEN
+        childcare_hours_per_day: 2
+        md_ccs_provider_type: INFORMAL
+      person5:
+        age: 30
+        employment_income: 40_000
+        is_tax_unit_head_or_spouse: true
+      person6:
+        age: 3
+        is_tax_unit_dependent: true
+        immigration_status: CITIZEN
+        childcare_hours_per_day: 2
+        md_ccs_provider_type: INFORMAL
+    tax_units:
+      tax_unit1:
+        members: [person1, person2]
+      tax_unit2:
+        members: [person3, person4]
+      tax_unit3:
+        members: [person5, person6]
+    spm_units:
+      spm_unit1:
+        members: [person1, person2]
+      spm_unit2:
+        members: [person3, person4]
+      spm_unit3:
+        members: [person5, person6]
+    households:
+      household1:
+        members: [person1, person2]
+        state_code: MD
+        county: MONTGOMERY_COUNTY_MD
+      household2:
+        members: [person3, person4]
+        state_code: MD
+        county: UNKNOWN
+      household3:
+        members: [person5, person6]
+        state_code: VA
+        county: FAIRFAX_COUNTY_VA
+  output:
+    # person2: informal, Montgomery, REGULAR (age 3), UNIT_1 (2 hours):
+    #   $177 / 3 = $59/week.
+    # person4: UNKNOWN county falls back to Allegany, informal REGULAR
+    #   UNIT_1: $83 / 3 = $27.67/week.
+    # person6: Virginia; defined_for zeroes the result.
+    md_ccs_payment_rate: [0, 59, 0, 27.67, 0, 0]

policyengine_us/tests/policy/baseline/gov/states/mn/dcyf/ccap/mn_ccap_provider_rate.yaml

@@ -241,3 +241,44 @@
         county: MILWAUKEE_COUNTY_WI
   output:
     mn_ccap_provider_rate: 0
+
+- name: Case 13, unknown-county and out-of-state households in one simulation with a Becker County household.
+  # defined_for masks the output but the formula still runs over every
+  # household in the simulation. Before the UNKNOWN guard, the Minnesota
+  # household with an UNKNOWN county reached the county-keyed rate tables and
+  # raised ParameterNotFoundError.
+  period: 2026-01
+  absolute_error_margin: 0.01
+  input:
+    people:
+      person1:
+        age: 0
+        childcare_hours_per_week: 45
+        mn_ccap_provider_type: FAMILY_CHILD_CARE
+      person2:
+        age: 0
+        childcare_hours_per_week: 45
+        mn_ccap_provider_type: FAMILY_CHILD_CARE
+      person3:
+        age: 0
+        childcare_hours_per_week: 45
+        mn_ccap_provider_type: FAMILY_CHILD_CARE
+    households:
+      household1:
+        members: [person1]
+        state_code: MN
+        county: BECKER_COUNTY_MN
+      household2:
+        members: [person2]
+        state_code: MN
+        county: UNKNOWN
+      household3:
+        members: [person3]
+        state_code: WI
+        county: MILWAUKEE_COUNTY_WI
+  output:
+    # person1: Becker family infant weekly 205 -> 205 * 52 / 12 = 888.33.
+    # person2: UNKNOWN county falls back to Hennepin, family infant weekly
+    #   250 -> 250 * 52 / 12 = 1,083.33.
+    # person3: Wisconsin; defined_for zeroes the result.
+    mn_ccap_provider_rate: [888.33, 1_083.33, 0]

policyengine_us/tests/policy/baseline/gov/states/vt/tax/income/credits/rent/vt_renter_credit.yaml

@@ -145,3 +145,134 @@
     state_code: VT
   output:
     vt_renter_credit: 1_692
+
+- name: test 11, out-of-state and unknown-county households in one simulation with a Chittenden County household.
+  # defined_for masks the output but the formula still runs over every
+  # household in the simulation. Before the county guard, the New Hampshire
+  # county and the UNKNOWN county reached the Vermont county-keyed tables and
+  # raised ParameterNotFoundError.
+  period: 2025
+  input:
+    people:
+      person1:
+        age: 40
+      person2:
+        age: 40
+      person3:
+        age: 40
+    tax_units:
+      tax_unit1:
+        members: [person1]
+        tax_unit_size: 2
+        vt_renter_credit_income: 49_370
+        rent_is_shared_with_another_tax_unit: false
+      tax_unit2:
+        members: [person2]
+        tax_unit_size: 2
+        vt_renter_credit_income: 49_370
+        rent_is_shared_with_another_tax_unit: false
+      tax_unit3:
+        members: [person3]
+        tax_unit_size: 2
+        vt_renter_credit_income: 44_145
+        rent_is_shared_with_another_tax_unit: false
+    spm_units:
+      spm_unit1:
+        members: [person1]
+        housing_assistance: 0
+      spm_unit2:
+        members: [person2]
+        housing_assistance: 0
+      spm_unit3:
+        members: [person3]
+        housing_assistance: 0
+    households:
+      household1:
+        members: [person1]
+        state_code: VT
+        county: CHITTENDEN_COUNTY_VT
+      household2:
+        members: [person2]
+        state_code: NH
+        county: GRAFTON_COUNTY_NH
+      household3:
+        members: [person3]
+        state_code: VT
+        county: UNKNOWN
+  output:
+    # tax_unit1: Chittenden 2025, size 2: full credit limit 31,200, partial
+    #   credit limit 67,540, fair market rent 1,936.
+    #   (67,540 - 49,370) / (67,540 - 31,200) = 0.5;
+    #   0.5 * 1,936 * 12 * 0.1 = 1,161.6 -> 1,162.
+    # tax_unit2: New Hampshire; defined_for zeroes the result.
+    # tax_unit3: UNKNOWN county falls back to Addison 2025, size 2: limits
+    #   27,900 and 60,390, fair market rent 1,410.
+    #   (60,390 - 44,145) / (60,390 - 27,900) = 0.5;
+    #   0.5 * 1,410 * 12 * 0.1 = 846. (Chittenden would give 1,496.)
+    # The Department of Taxes 2025 Renter Credit Website Calculator gives
+    # 1,162 (Chittenden) and 846 (Addison) for these inputs.
+    vt_renter_credit: [1_162, 0, 846]
+
+- name: test 12, tax units of nine or more use the eight-person income limits and fair market rent.
+  # The income limit and fair market rent tables run through family size 8.
+  # The Department of Taxes renter credit calculator looks up
+  # IF(Household_Size>8,8,Household_Size), so larger households use the
+  # 8-person values. Before the size cap, sizes 9 and 12 raised
+  # ParameterNotFoundError even with only Vermont households.
+  period: 2025
+  input:
+    people:
+      person1:
+        age: 40
+      person2:
+        age: 40
+      person3:
+        age: 40
+    tax_units:
+      tax_unit1:
+        members: [person1]
+        tax_unit_size: 8
+        vt_renter_credit_income: 82_780
+        rent_is_shared_with_another_tax_unit: false
+      tax_unit2:
+        members: [person2]
+        tax_unit_size: 9
+        vt_renter_credit_income: 82_780
+        rent_is_shared_with_another_tax_unit: false
+      tax_unit3:
+        members: [person3]
+        tax_unit_size: 12
+        vt_renter_credit_income: 82_780
+        rent_is_shared_with_another_tax_unit: false
+    spm_units:
+      spm_unit1:
+        members: [person1]
+        housing_assistance: 0
+      spm_unit2:
+        members: [person2]
+        housing_assistance: 0
+      spm_unit3:
+        members: [person3]
+        housing_assistance: 0
+    households:
+      household1:
+        members: [person1]
+        state_code: VT
+        county: CHITTENDEN_COUNTY_VT
+      household2:
+        members: [person2]
+        state_code: VT
+        county: CHITTENDEN_COUNTY_VT
+      household3:
+        members: [person3]
+        state_code: VT
+        county: CHITTENDEN_COUNTY_VT
+  output:
+    # Chittenden 2025, size 8: full credit limit 54,150, partial credit limit
+    # 111,410, fair market rent 2,083.
+    # (111,410 - 82,780) / (111,410 - 54,150) = 0.5;
+    # 0.5 * 2,083 * 12 * 0.1 = 1,249.8 -> 1,250 for all three tax units.
+    # (The 7-person limits, 48,650 and 104,650, would give 976.)
+    # The Department of Taxes 2025 Renter Credit Website Calculator gives
+    # 1,250 for family sizes 8, 9 and 10 (its maximum input) and 976 for 7.
+    vt_renter_credit: [1_250, 1_250, 1_250]

policyengine_us/tests/policy/baseline/gov/states/wi/dcf/shares/rates/wi_shares_hourly_max_rate.yaml

@@ -145,3 +145,44 @@
   output:
     # defined_for wi_shares_eligible_child zeroes the rate.
     wi_shares_hourly_max_rate: 0
+
+- name: Case 9, unknown-county and out-of-state households in one simulation with a Milwaukee County household.
+  # defined_for masks the output but the formula still runs over every
+  # household in the simulation. Before the UNKNOWN guard, the Wisconsin
+  # household with an UNKNOWN county reached the county-keyed rate tables and
+  # raised ParameterNotFoundError.
+  period: 2027-01
+  absolute_error_margin: 0.01
+  input:
+    people:
+      person1:
+        age: 3
+        childcare_hours_per_week: 20
+        wi_shares_provider_type: LICENSED_GROUP
+      person2:
+        age: 3
+        childcare_hours_per_week: 20
+        wi_shares_provider_type: LICENSED_GROUP
+      person3:
+        age: 3
+        childcare_hours_per_week: 20
+        wi_shares_provider_type: LICENSED_GROUP
+    households:
+      household1:
+        members: [person1]
+        state_code: WI
+        county: MILWAUKEE_COUNTY_WI
+      household2:
+        members: [person2]
+        state_code: WI
+        county: UNKNOWN
+      household3:
+        members: [person3]
+        state_code: MN
+        county: HENNEPIN_COUNTY_MN
+  output:
+    # person1: Milwaukee licensed group, ages 2-3: 9.72.
+    # person2: UNKNOWN county falls back to Adams licensed group, ages 2-3:
+    #   8.75.
+    # person3: Minnesota; defined_for zeroes the result.
+    wi_shares_hourly_max_rate: [9.72, 8.75, 0]

policyengine_us/tests/policy/baseline/gov/states/wi/dcf/shares/rates/wi_shares_monthly_max_rate.yaml

@@ -97,3 +97,45 @@
     # Licensed family hourly 8.15 x 131 part-time monthly hours = 1,067.65,
     # not the certified hourly (7.34) x 131.
     wi_shares_monthly_max_rate: 1_067.65
+
+- name: Case 6, unknown-county and out-of-state households in one simulation with a Milwaukee County household.
+  # defined_for masks the output but the formula still runs over every
+  # household in the simulation. Before the UNKNOWN guard, the Wisconsin
+  # household with an UNKNOWN county reached the county-keyed rate tables and
+  # raised ParameterNotFoundError.
+  period: 2027-01
+  absolute_error_margin: 0.01
+  input:
+    people:
+      person1:
+        age: 3
+        childcare_hours_per_week: 15
+        wi_shares_provider_type: LICENSED_GROUP
+      person2:
+        age: 3
+        childcare_hours_per_week: 15
+        wi_shares_provider_type: LICENSED_GROUP
+      person3:
+        age: 3
+        childcare_hours_per_week: 15
+        wi_shares_provider_type: LICENSED_GROUP
+    households:
+      household1:
+        members: [person1]
+        state_code: WI
+        county: MILWAUKEE_COUNTY_WI
+      household2:
+        members: [person2]
+        state_code: WI
+        county: UNKNOWN
+      household3:
+        members: [person3]
+        state_code: MN
+        county: HENNEPIN_COUNTY_MN
+  output:
+    # person1: Milwaukee licensed group hourly 9.72 x 131 part-time monthly
+    #   hours = 1,273.32.
+    # person2: UNKNOWN county falls back to Adams licensed group hourly 8.75
+    #   x 131 = 1,146.25.
+    # person3: Minnesota; defined_for zeroes the result.
+    wi_shares_monthly_max_rate: [1_273.32, 1_146.25, 0]

policyengine_us/variables/gov/states/md/msde/ccs/payment/md_ccs_payment_rate.py

@@ -27,9 +27,14 @@ def formula(person, period, parameters):
         center_rate = p.formal.licensed_center[region][age_group] * unit_share
         family_rate = p.formal.licensed_family[region][age_group] * unit_share
 
+        # defined_for does not short-circuit vectorized execution, so
+        # non-Maryland counties are masked before indexing the county-keyed
+        # informal rate table. The table has no UNKNOWN key either, so a
+        # Maryland household with an unknown county also falls back to
+        # Allegany.
         county = person.household("county_str", period)
         in_md = person.household("state_code_str", period) == "MD"
-        safe_county = where(in_md, county, "ALLEGANY_COUNTY_MD")
+        safe_county = where(in_md & (county != "UNKNOWN"), county, "ALLEGANY_COUNTY_MD")
         informal_rate = p.informal.rates[safe_county][age_group] * unit_share
 
         return select(