Implement Guaranteed Income Supplement (GIS)

policyengine_canada/parameters/gov/cra/benefits/guaranteed_income_supplement/amount/couple_both_oas.yaml

@@ -0,0 +1,13 @@
+description: Maximum monthly GIS when spouse/partner receives full OAS pension
+values:
+  2022-01-01: 619.99
+  2023-01-01: 641.80
+  2024-01-01: 652.96
+  2025-01-01: 660.78
+metadata:
+  unit: currency-CAD
+  period: month
+  label: GIS maximum amount for couples (both receive OAS)
+  reference:
+    - title: Old Age Security payment amounts
+      href: https://www.canada.ca/en/services/benefits/publicpensions/cpp/old-age-security/payments.html

policyengine_canada/parameters/gov/cra/benefits/guaranteed_income_supplement/amount/single.yaml

@@ -0,0 +1,13 @@
+description: Maximum monthly Guaranteed Income Supplement for single seniors
+values:
+  2022-01-01: 1_028.96
+  2023-01-01: 1_065.47
+  2024-01-01: 1_083.68
+  2025-01-01: 1_097.75
+metadata:
+  unit: currency-CAD
+  period: month
+  label: GIS maximum amount for singles
+  reference:
+    - title: Old Age Security payment amounts
+      href: https://www.canada.ca/en/services/benefits/publicpensions/cpp/old-age-security/payments.html

policyengine_canada/parameters/gov/cra/benefits/guaranteed_income_supplement/reduction_rate.yaml

@@ -0,0 +1,11 @@
+description: GIS reduction rate per dollar of income
+values:
+  2022-01-01: 0.5
+metadata:
+  unit: /1
+  label: GIS reduction rate
+  reference:
+    - title: Old Age Security Act - Guaranteed Income Supplement
+      href: https://laws-lois.justice.gc.ca/eng/acts/o-9/page-3.html#h-387820
+    - title: Government of Canada - GIS Overview
+      href: https://www.canada.ca/en/services/benefits/publicpensions/cpp/old-age-security/guaranteed-income-supplement/eligibility.html

policyengine_canada/parameters/gov/cra/benefits/guaranteed_income_supplement/threshold/couple_both_oas.yaml

@@ -0,0 +1,13 @@
+description: Combined annual income threshold for GIS when both receive OAS
+values:
+  2022-01-01: 27_552
+  2023-01-01: 28_560
+  2024-01-01: 28_800
+  2025-01-01: 29_424
+metadata:
+  unit: currency-CAD
+  period: year
+  label: GIS income threshold for couples (both OAS)
+  reference:
+    - title: Old Age Security payment amounts
+      href: https://www.canada.ca/en/services/benefits/publicpensions/cpp/old-age-security/payments.html

policyengine_canada/parameters/gov/cra/benefits/guaranteed_income_supplement/threshold/single.yaml

@@ -0,0 +1,13 @@
+description: Annual income threshold for GIS eligibility for singles
+values:
+  2022-01-01: 20_784
+  2023-01-01: 21_624
+  2024-01-01: 21_768
+  2025-01-01: 22_272
+metadata:
+  unit: currency-CAD
+  period: year
+  label: GIS income threshold for singles
+  reference:
+    - title: Old Age Security payment amounts
+      href: https://www.canada.ca/en/services/benefits/publicpensions/cpp/old-age-security/payments.html

policyengine_canada/tests/gov/cra/benefits/gis/gis.yaml

@@ -0,0 +1,125 @@
+- name: Single senior with no income gets maximum GIS
+  period: 2024
+  input:
+    age: 70
+    adult_years_in_canada: 50
+    is_head: true
+    is_spouse: false
+    employment_income: 0
+    self_employment_income: 0
+  output:
+    # Maximum monthly for 2024 is $1,083.68
+    # Annual: $1,083.68 * 12 = $13,004.16
+    gis: 13_004.16
+
+- name: Single senior with income at threshold gets minimal GIS
+  period: 2024
+  input:
+    age: 70
+    adult_years_in_canada: 50
+    is_head: true
+    is_spouse: false
+    employment_income: 21_768  # Near threshold for 2024
+    self_employment_income: 0
+  output:
+    # Income: $21,768
+    # Reduction: $21,768 * 0.5 = $10,884
+    # GIS: $13,004.16 - $10,884 = $2,120.16
+    gis: 2_120.16
+
+- name: Single senior with partial income gets reduced GIS
+  period: 2024
+  input:
+    age: 70
+    adult_years_in_canada: 50
+    is_head: true
+    is_spouse: false
+    employment_income: 10_000
+    self_employment_income: 0
+  output:
+    # Income: $10,000
+    # Reduction: $10,000 * 0.5 = $5,000
+    # GIS: $13,004.16 - $5,000 = $8,004.16
+    gis: 8_004.16
+
+- name: Single senior with income above threshold gets reduced GIS
+  period: 2024
+  input:
+    age: 70
+    adult_years_in_canada: 50
+    is_head: true
+    is_spouse: false
+    employment_income: 22_000
+    self_employment_income: 0
+  output:
+    # Income: $22,000
+    # Reduction: $22,000 * 0.5 = $11,000
+    # GIS: $13,004.16 - $11,000 = $2,004.16
+    gis: 2_004.16
+
+- name: Not eligible due to age
+  period: 2024
+  input:
+    age: 60
+    adult_years_in_canada: 40
+    is_head: true
+    is_spouse: false
+    employment_income: 0
+    self_employment_income: 0
+  output:
+    gis: 0
+
+- name: Single senior with high income gets no GIS
+  period: 2024
+  input:
+    age: 70
+    adult_years_in_canada: 50
+    is_head: true
+    is_spouse: false
+    employment_income: 50_000
+    self_employment_income: 0
+  output:
+    gis: 0
+
+- name: Couple where both receive OAS with no income
+  period: 2024
+  input:
+    people:
+      head:
+        age: 70
+        adult_years_in_canada: 50
+        is_head: true
+        employment_income: 0
+      spouse:
+        age: 68
+        adult_years_in_canada: 45
+        is_spouse: true
+        employment_income: 0
+    household:
+      members: [head, spouse]
+  output:
+    # Maximum monthly for couple both OAS is $652.96
+    # Annual: $652.96 * 12 = $7,835.52 per person
+    gis: [7_835.52, 7_835.52]
+
+- name: Couple with combined income gets reduced GIS
+  period: 2024
+  input:
+    people:
+      head:
+        age: 70
+        adult_years_in_canada: 50
+        is_head: true
+        employment_income: 10_000
+      spouse:
+        age: 68
+        adult_years_in_canada: 45
+        is_spouse: true
+        employment_income: 5_000
+    household:
+      members: [head, spouse]
+  output:
+    # Combined income: $15,000
+    # Reduction: $15,000 * 0.5 = $7,500
+    # GIS: $7,835.52 - $7,500 = $335.52 per person
+    gis: [335.52, 335.52]

policyengine_canada/tests/gov/cra/benefits/gis/gis_eligible.yaml

@@ -0,0 +1,39 @@
+- name: 65 year old with low income is eligible
+  period: 2024
+  input:
+    age: 65
+    adult_years_in_canada: 40
+    employment_income: 5_000
+    self_employment_income: 0
+  output:
+    gis_eligible: true
+
+- name: 65 year old with high income is not eligible
+  period: 2024
+  input:
+    age: 65
+    adult_years_in_canada: 40
+    employment_income: 50_000
+    self_employment_income: 0
+  output:
+    gis_eligible: false
+
+- name: 64 year old is not eligible (too young for OAS)
+  period: 2024
+  input:
+    age: 64
+    adult_years_in_canada: 40
+    employment_income: 5_000
+    self_employment_income: 0
+  output:
+    gis_eligible: false
+
+- name: 65 year old with insufficient residency is not eligible
+  period: 2024
+  input:
+    age: 65
+    adult_years_in_canada: 5  # Less than 10 years required for OAS
+    employment_income: 5_000
+    self_employment_income: 0
+  output:
+    gis_eligible: false

policyengine_canada/tests/gov/cra/benefits/gis/gis_income.yaml

@@ -0,0 +1,31 @@
+- name: Employment income only
+  period: 2024
+  input:
+    employment_income: 15_000
+    self_employment_income: 0
+  output:
+    gis_income: 15_000
+
+- name: Self-employment income only
+  period: 2024
+  input:
+    employment_income: 0
+    self_employment_income: 20_000
+  output:
+    gis_income: 20_000
+
+- name: Mixed employment and self-employment income
+  period: 2024
+  input:
+    employment_income: 10_000
+    self_employment_income: 8_000
+  output:
+    gis_income: 18_000
+
+- name: No income
+  period: 2024
+  input:
+    employment_income: 0
+    self_employment_income: 0
+  output:
+    gis_income: 0

policyengine_canada/variables/gov/benefits.py

@@ -13,6 +13,7 @@ class benefits(Variable):
         "canada_workers_benefit",
         "dental_benefit",
         "oas_net",
+        "gis",
         # Ontario programs.
         "on_benefits",
         # British Columbia programs.

policyengine_canada/variables/gov/cra/benefits/guaranteed_income_supplement/gis.py

@@ -0,0 +1,64 @@
+from policyengine_canada.model_api import *
+
+
+class gis(Variable):
+    value_type = float
+    entity = Person
+    label = "Guaranteed Income Supplement"
+    unit = CAD
+    definition_period = YEAR
+    documentation = "Annual Guaranteed Income Supplement payment for low-income seniors"
+
+    def formula(person, period, parameters):
+        # Check eligibility
+        eligible = person("gis_eligible", period)
+
+        if not eligible.any():
+            return person.empty_array()
+
+        # Get GIS-specific income
+        gis_income = person("gis_income", period)
+
+        # Get marital status at person level
+        is_head = person("is_head", period)
+        is_spouse = person("is_spouse", period)
+
+        # Check if household is single (will be same for all household members)
+        is_single_household = person.household("is_single", period)
+
+        # Get parameters
+        p_gis = parameters(period).gov.cra.benefits.guaranteed_income_supplement
+
+        # Calculate base amount and threshold based on marital status
+        # For now, simplified to single vs couple where both get OAS
+        # TODO: Add other couple scenarios (spouse no OAS, spouse gets Allowance)
+        max_amount = where(
+            is_single_household,
+            p_gis.amount.single * 12,  # Convert monthly to annual
+            p_gis.amount.couple_both_oas * 12
+        )
+
+        income_threshold = where(
+            is_single_household,
+            p_gis.threshold.single,
+            p_gis.threshold.couple_both_oas
+        )
+
+        # For couples, use combined income
+        # Aggregate household income for GIS calculation
+        household_gis_income = where(
+            is_single_household,
+            gis_income,
+            person.household.sum(gis_income)  # Sum all household members' GIS income
+        )
+
+        # Calculate reduction based on income
+        # GIS is reduced by 50 cents for every dollar of income
+        # The threshold is actually the maximum income to receive any GIS
+        reduction = household_gis_income * p_gis.reduction_rate
+
+        # Calculate final benefit
+        gis_benefit = max_(0, max_amount - reduction)
+
+        # Apply eligibility
+        return where(eligible, gis_benefit, 0)

policyengine_canada/variables/gov/cra/benefits/guaranteed_income_supplement/gis_eligible.py

@@ -0,0 +1,33 @@
+from policyengine_canada.model_api import *
+
+
+class gis_eligible(Variable):
+    value_type = bool
+    entity = Person
+    label = "Guaranteed Income Supplement eligibility"
+    definition_period = YEAR
+    documentation = "Eligibility for the Guaranteed Income Supplement based on OAS eligibility and income"
+
+    def formula(person, period, parameters):
+        # Must be receiving OAS to get GIS
+        oas_eligible = person("oas_eligibility", period)
+
+        # Income test - simplified for now, will be refined with proper income calculation
+        # GIS uses a special income definition that excludes OAS but includes most other income
+        employment_income = person("employment_income", period)
+        self_employment_income = person("self_employment_income", period)
+
+        # For now, use basic income for eligibility
+        # This will need to be expanded to include other income sources
+        gis_income = employment_income + self_employment_income
+
+        p_gis = parameters(period).gov.cra.benefits.guaranteed_income_supplement
+
+        # For singles, check if income would still result in positive GIS
+        # Maximum GIS phases out at twice the maximum amount (at 50% reduction rate)
+        # TODO: Add proper couple handling
+        max_gis = p_gis.amount.single * 12
+        phase_out_income = max_gis / p_gis.reduction_rate
+        income_eligible = gis_income < phase_out_income
+
+        return oas_eligible & income_eligible