Add New Mexico SSI State Supplement

[MaxGhenis]

Summary

Implements the New Mexico SSI State Supplement, a flat $100/month payment for SSI recipients living in licensed Adult Residential Shelter Care Homes (ARSCH).

Closes #7345

Regulatory authority

• Statute: NMSA 1978, Section 27-2-9.1 ("Administration of shelter care supplement")
• Regulations: 8.106.500.10 NMAC (effective March 1, 2025) - source
• Benefit groups: 8.106.400.10 NMAC - couples treated as separate benefit groups
• Definitions: 8.106.100.7 NMAC - ARSCH facility definition
• Administering agency: New Mexico Health Care Authority (HCA), Income Support Division

Program details

Feature	Value
Payment amount	$100/month (flat)
Eligibility	SSI recipients aged 18+ in licensed ARSCH facilities
Calculation	Flat payment (not gap-fill)
Program type	Optional State Supplementary Payment (OSS)
Effective since	At least July 1, 2004

Eligibility criteria (8.106.500.10 NMAC)

1. Must be receiving SSI under Title XVI
2. Must reside in a licensed ARSCH facility
3. Must be age 18 or older
4. No additional state income/resource tests beyond federal SSI

Benefit calculation

If eligible: $100/month × 12 = $1,200/year
If not eligible: $0

Couples in ARSCH facilities are treated as two separate benefit groups per 8.106.400.10 NMAC, so each eligible person receives $100/month individually.

Files added

Parameters

• parameters/gov/states/nm/hca/ssi_supplement/amount.yaml - $100/month payment
• parameters/gov/states/nm/hca/ssi_supplement/min_age.yaml - Age 18 minimum

Variables

• variables/gov/states/nm/hca/ssi_supplement/is_in_adult_residential_care.py - Input variable for ARSCH residence
• variables/gov/states/nm/hca/ssi_supplement/nm_ssi_state_supplement_eligible.py - Eligibility check
• variables/gov/states/nm/hca/ssi_supplement/nm_ssi_state_supplement.py - Benefit calculation

Tests (18 test cases)

• tests/.../nm_ssi_state_supplement_eligible.yaml - 7 eligibility unit tests
• tests/.../nm_ssi_state_supplement.yaml - 4 benefit amount unit tests
• tests/.../integration.yaml - 7 integration tests (couples, mixed households, edge cases)

Modified

• parameters/gov/household/household_state_benefits.yaml - Added nm_ssi_state_supplement to state benefits list

Test coverage

Scenario	Eligible	Amount
SSI recipient (65) in ARSCH, NM	Yes	$1,200/yr
Disabled adult (35) in ARSCH, NM	Yes	$1,200/yr
Age 18 boundary, in ARSCH, NM	Yes	$1,200/yr
Couple (68, 66) in ARSCH, NM	Both yes	$1,200 each
Not SSI-eligible, in ARSCH, NM	No	$0
Under 18, in ARSCH, NM	No	$0
SSI recipient, NOT in ARSCH, NM	No	$0
SSI recipient, in ARSCH, TX	No	$0
Mixed household (1 eligible, 1 not)	Mixed	$1,200/$0

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 100.00%. Comparing base (a46b5a8) to head (de2d056).
⚠️ Report is 29 commits behind head on main.

Additional details and impacted files

@@             Coverage Diff              @@
##             main     #7346       +/-   ##
============================================
+ Coverage   86.56%   100.00%   +13.43%     
============================================
  Files          12         3        -9     
  Lines         134        35       -99     
============================================
- Hits          116        35       -81     
+ Misses         18         0       -18     

Flag	Coverage Δ
unittests	100.00% <100.00%> (+13.43%)	⬆️

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