Implement Alaska State Supplementary Payment (SSP)

[hua7450]

Summary

Implements Alaska's State Supplementary Payment (SSP) -- the state supplement to federal SSI, administered as Adult Public Assistance (APA) by the Division of Public Assistance (DPA).

Closes #7872

Regulatory Authority

• AS 47.25.430-47.25.615 (Alaska Adult Public Assistance statutes)
• APA Manual Chapter 452 -- Payments
• SSA State Assistance Programs for SSI Recipients, January 2011
• Alaska DPA APA Need and Maximum Payment Standards 2023-2026
• Alaska DPA APA Need and Maximum Payment Standards 2017-2020

Program Overview

• Administration: State-administered (Alaska Department of Health, Division of Public Assistance)
• Funding: State funds
• Current caseload: 17,630 recipients (January 2011, SSA report)
• Expenditures: $55,946,103 (calendar year 2010)

Eligibility

Requirement	Source	How Modeled
Must be SSI-eligible (aged 65+, blind, or disabled; meets income/resource tests)	SSA report p.1; AS 47.25.430	is_ssi_eligible
Must be age 18 or older (children excluded from APA)	SSA report p.1	age >= age_threshold (parameter: eligibility/age_threshold, 18 since 1974)
Must reside in Alaska	State program	defined_for = StateCode.AK

Benefit Amounts (SSA report Table 1; APA Standards 2023-2026)

Independent Living (Type A)

Category	Monthly Amount (2011-present)
Individual	$362
Couple, both eligible	$528
Couple, one eligible	$521

Type A amounts are constant across all years (state supplements stay fixed as federal COLA applies equally to both the federal benefit and the APA need standard).

Household of Another (Type B)

Category	Monthly Amount
Individual	$368 (2011); $367.66 (2023); $368.33 (2024)
Couple, both eligible	$543 (2011); $542.66 (2024); $543.33 (2025); $543 (2026)
Couple, one eligible	$464 (2011); $463.66 (2023); $464.33 (2024)

Type B amounts show rounding variations of +/- $0.34 across years because the Type B payment standard = (2/3 of federal benefit rate + state supplement), where the 2/3 factor introduces fractional cents.

Assisted Living (ALH)

Category	Monthly Amount (2011-present)
Individual	$100
Couple, both eligible	$200
Couple, one eligible	$100

Medicaid Facility / Nursing Home Personal Needs (NHP)

Category	Monthly Amount
Individual	$45 (2011-2016); $170 (2017+)
Couple, both eligible	$90 (2011-2016); $340 (2017+)
Couple, one eligible	$45 (2011-2016); $170 (2017+)

NHP rate change: Nursing home personal needs allowance increased from $45 to $170/month effective 2017 (nearly 4x increase).

Couple treatment: Joint claims split evenly per APA Manual 452-8. Implemented via marital_unit.sum(supplement) / 2.

COLA: APA standards increase by the same dollar amount as the federal SSI COLA, keeping state supplements constant (except Type B rounding variations and the NHP increase in 2017).

Income Reduction Logic

The state supplement is reduced dollar-for-dollar by income that exceeds the federal SSI benefit level. This is computed using uncapped_ssi (which can be negative when countable income exceeds the SSI benefit):

• income_excess = max(0, -uncapped_ssi)
• state_supplement = max(0, payment_standard - income_excess)

This correctly handles the "gap zone" where a person's income is too high for federal SSI but still below the APA need standard.

Not Modeled (by design)

What	Source	Why Excluded
Pioneer Home / institution exclusion	SSA report	No input variable tracks Pioneer Home residency
Disabled Kids at Home (waiver category)	APA Standards PDF	Waiver-specific; children excluded from APA by age requirement
Waiver recipients (ASL, WAV)	APA Manual 452	Waiver participation not tracked as input variable
Nursing Home Regular (NHR), NH 300% (NH3)	APA Manual 452	Separate nursing home payment categories beyond standard NHP
In-kind income exclusion	SSA report	Federal SSI income counting already handles this
Non-SSI APA recipients	APA Manual 452-2	People with income between SSI threshold and APA need standard -- requires separate income test not yet in model
$1/month minimum benefit for pre-2020 gap zone	APA Manual 452	Edge case for gap zone recipients
Ineligible spouse budgeting exception	APA Manual 452-2	Rare exception to standard deeming

Files

policyengine_us/parameters/gov/states/ak/dpa/ssp/
  eligibility/age_threshold.yaml    # Age 18+ since 1974
  payment_standard.yaml             # Supplement amounts by living arrangement x claim type (2011-2026)

policyengine_us/variables/gov/states/ak/dpa/ssp/
  ak_ssp.py                         # Main benefit variable (income reduction + joint claim splitting)
  ak_ssp_eligible.py                # Eligibility: is_ssi_eligible & age >= 18
  ak_ssp_living_arrangement.py      # Enum: INDEPENDENT, HOUSEHOLD_OF_ANOTHER, ASSISTED_LIVING, MEDICAID_FACILITY
  ak_ssp_claim_type.py              # Enum: INDIVIDUAL, COUPLE_BOTH_ELIGIBLE, COUPLE_ONE_ELIGIBLE
  ak_ssp_payment_standard.py        # Lookup: payment_standard[living_arrangement][claim_type] * 12

policyengine_us/tests/policy/baseline/gov/states/ak/dpa/ssp/
  ak_ssp.yaml                       # 8 unit tests (benefit formula)
  ak_ssp_eligible.yaml              # 7 unit tests (eligibility)
  ak_ssp_payment_standard.yaml      # 15 unit tests (all arrangement x claim type combos + NHP rate change)
  ak_ssp_claim_type.yaml            # 4 unit tests (claim type derivation)
  integration.yaml                  # 13 integration tests (end-to-end with full entity structure)

Verification TODO

• Verify payment amounts against APA Standards PDF
• Verify eligibility logic against APA Manual Ch.452
• Verify amounts current as of 2011-2026
• CI passes

Test plan

• 47 tests pass (8 benefit + 7 eligibility + 15 payment standard + 4 claim type + 13 integration)
• CI passes

[codecov]

Codecov Report

❌ Patch coverage is 73.68421% with 25 lines in your changes missing coverage. Please review.
✅ Project coverage is 70.98%. Comparing base (ac35815) to head (63da80c).
⚠️ Report is 45 commits behind head on main.

Files with missing lines	Patch %	Lines
...us/variables/gov/ssa/ssi/ssi_amount_if_eligible.py	0.00%	7 Missing ⚠️
...s/gov/states/ak/dpa/ssp/ak_ssp_payment_standard.py	62.50%	6 Missing ⚠️
...ngine_us/variables/gov/states/ak/dpa/ssp/ak_ssp.py	68.75%	5 Missing ⚠️
...riables/gov/states/ak/dpa/ssp/ak_ssp_claim_type.py	75.00%	5 Missing ⚠️
...variables/gov/states/ak/dpa/ssp/ak_ssp_eligible.py	81.81%	2 Missing ⚠️

Additional details and impacted files

@@             Coverage Diff              @@
##              main    #7873       +/-   ##
============================================
- Coverage   100.00%   70.98%   -29.02%     
============================================
  Files            2     4109     +4107     
  Lines           32    59411    +59379     
  Branches         0      290      +290     
============================================
+ Hits            32    42170    +42138     
- Misses           0    17240    +17240     
- Partials         0        1        +1     

Flag	Coverage Δ
unittests	70.98% <73.68%> (-29.02%)	⬇️

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[MaxGhenis]

I pushed follow-up fixes here.

What changed:

• corrected the Alaska SSP payment logic so the supplement is computed on the right base amount
• fixed the claim-type logic for one-eligible-couple cases
• final follow-up was formatting only

[MaxGhenis]

Reviewed the Alaska SSP follow-up fixes.