Backfill NY TANF parameters to 1997 with pre-2022 and post-2022 reform rules

[hua7450]

Summary

Fixes #7177
Fixes #6993

Implements complete NY TANF modeling with both pre-October 2022 and post-October 2022 reform rules. The October 2022 reforms (22-ADM-11) significantly changed the earned income calculation methodology and eliminated the gross income test.

Regulatory Authority

• 22-ADM-11 - Public Assistance Policy Changes Included in the SFY 2022-23 New York State Budget (effective October 1, 2022)
• 97-ADM-23 - Family Assistance/Safety Net Assistance Changes (original 1998 rules)
• 18 NYCRR 352.1 - Standard of need for determining eligibility

Income Eligibility Tests

Gross Income Test (Pre-October 2022 Only)

Period	Test
1998-01-01 to 2022-09-30	Gross income ≤ Need Standard × 185%
2022-10-01 onwards	Eliminated

Source: 22-ADM-11 Section IV(B)

Needs Test (Always Applies)

Countable income < Need Standard

Income Deductions & Exemptions

Earned Income Disregard (EID) Rate

Effective Date	Rate
1998-01-01	42%
2022-06-01	55%
2022-10-01	50%

Source: 97-ADM-23, 22-ADM-11 Section IV(B)

Work Expense Disregard

Effective Date	Amount
1998-01-01	$90
2022-10-01	$150

Source: 97-ADM-23, 22-ADM-11 Section IV(B)

Calculation Order Change (Critical)

Period	Order
Pre-October 2022	Work expense FIRST, then EID: max(gross - $90, 0) × (1 - 42%)
Post-October 2022	EID FIRST, then work expense: max(gross × (1 - 50%) - $150, 0)

Source: 22-ADM-11 Section II

Resource Limits

Household Type	Pre-October 2022	Post-October 2022
Standard	$2,000	$2,500
Elderly (60+)	$3,000	$3,750
Disabled	$2,000 (standard)	$3,750 (added by reform)

Source: 97-ADM-23, 22-ADM-11 Section IV(A)

Need Standard (Monthly)

Household Size	Amount
1	$158
2	$252
3	$336
4	$433
5	$534
6	$617
7+	$617 + $85 per additional

Source: NY TANF State Plan 2024-2026

Benefit Calculation

Benefit = max(Need Standard - Countable Income, 0)

Where:

• Countable Income = Countable Earned Income + Gross Unearned Income
• Countable Earned Income = calculated per EID order rules above

Implementation Structure

Parameters

tanf/
├── gross_income_test/
│   └── rate.yaml
├── income/
│   └── earned_income_deduction/
│       ├── flat.yaml
│       └── percent.yaml
├── need_standard/
│   ├── additional.yaml
│   ├── main.yaml
│   └── max_table_size.yaml
├── reform_2022/
│   └── in_effect.yaml
└── resource_limit/
    ├── higher/
    │   ├── age_threshold.yaml
    │   └── amount.yaml
    └── lower/
        └── amount.yaml

Variables

tanf/
├── eligibility/
│   ├── ny_tanf_eligible.py
│   ├── ny_tanf_gross_income_eligible.py
│   ├── ny_tanf_income_eligible.py
│   └── ny_tanf_resources_eligible.py
├── income/
│   ├── ny_tanf_countable_earned_income.py
│   └── ny_tanf_countable_income.py
├── ny_tanf_need_standard.py
└── ny_tanf.py

Key Implementation Details

• reform_2022.in_effect parameter controls which rule set applies
• ny_tanf_income_eligible uses where() for vectorized reform logic
• ny_tanf_resources_eligible checks disability only when reform is in effect
• ny_tanf_eligible includes immigration check via federal is_citizen_or_legal_immigrant
• ny_tanf_countable_income uses adds to aggregate income (no formula needed)

Test Plan

• Pre-reform tests (period: 2022-01) verify work expense first, then EID calculation
• Post-reform tests (period: 2023-01) verify EID first, then work expense calculation
• Gross income test verified for pre-2022 (185% threshold)
• Gross income test verified as eliminated for post-2022
• Resource limits verified for both periods (including disability qualifier)
• Integration tests verify full eligibility and benefit chain
• All 53 NY TANF tests pass (7 unit test files + 1 integration test)

🤖 Generated with Claude Code

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 100.00%. Comparing base (d08239b) to head (d724d77).
⚠️ Report is 250 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##              main     #7178    +/-   ##
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  Coverage   100.00%   100.00%            
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  Files            1         8     +7     
  Lines           10       117   +107     
  Branches         0         1     +1     
==========================================
+ Hits            10       117   +107     

Flag	Coverage Δ
unittests	100.00% <100.00%> (ø)

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