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

[hua7450]

Summary

Fixes #7177

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 1997 rules)
• 18 NYCRR 352.23 - Use of resources-general policy
• 18 NYCRR 352.17 - Computation of available income

Income Eligibility Tests

Gross Income Test (Pre-October 2022 Only)

Period	Test
1997-08-20 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
1997-08-20	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
1997-08-20	$90
2022-10-01	$150

Source: 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 - EID%)
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/Disabled (60+)	$3,000	$3,750

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

Implementation Details

Parameters Created

• reform_2022/in_effect.yaml - Boolean controlling which rule set applies
• gross_income_test/rate.yaml - 185% multiplier for pre-2022 gross income test

Parameters Modified

• earned_income_deduction/percent.yaml - Historical EID rates (42%, 55%, 50%)
• earned_income_deduction/flat.yaml - Work expense amounts ($90, $150)
• Resource limit parameters backfilled to 1997

Variables Created

• ny_tanf_gross_income_eligible.py - 185% gross income test (eliminated post-October 2022)

Variables Modified

• ny_tanf_countable_earned_income.py - Conditional calculation order based on reform date
• ny_tanf_income_eligible.py - Added gross income test
• All NY TANF variables updated to definition_period = MONTH

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
• All 37 NY TANF tests pass

🤖 Generated with Claude Code

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 100.00%. Comparing base (f6b4cbb) to head (04598a6).
⚠️ Report is 26 commits behind head on main.

Additional details and impacted files

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##              main     #7178    +/-   ##
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  Coverage   100.00%   100.00%            
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  Files            1        11    +10     
  Lines           22       144   +122     
  Branches         1         2     +1     
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+ Hits            22       144   +122     

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

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