Implement Indiana TANF

[hua7450]

Summary

Implements Indiana's Temporary Assistance for Needy Families (TANF) program with comprehensive income eligibility tests, payment calculations, and resource limits.

Closes #6868

Status

• Parameters created (10 files)
• Variables implemented (12 files)
• Tests written (68 test cases)
• CI passing
• Formulas verified against Indiana statutes
• Ready for review

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Key Changes

Implementation Summary

• ✅ 12 new variables for Indiana TANF benefit calculation
• ✅ 10 parameter files for standard of need, income deductions, and resource limits
• ✅ 68 comprehensive test cases across 13 test files
• ✅ Formulas verified against 470 IAC 10.3-4
• ✅ All tests passing

Formula (Per 470 IAC 10.3-4)

Eligibility Income Disregards (Per earner + per unit):

# Per earner
after_work_expense = max(gross_earned - $90, 0)

# Per unit (sum of all earners first)
after_flat = max(unit_total - $30, 0)
countable_earned = after_flat × (1 - 1/3)  # = × 0.67

Payment Income Disregards:

countable_earned = gross_earned × 0.25  # 75% disregarded

Benefit Calculation:

benefit = MAX(standard_of_need - countable_income_for_payment, 0)

Two Income Tests Required:

• Countable income < standard of need (initial) or < 100% FPL (continuing)
• Payment countable income < standard of need

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Files Added

Parameters (10 files)

policyengine_us/parameters/gov/states/in/fssa/tanf/
├── eligibility/continuing/fpg_rate.yaml            # 100% FPL
├── income/deductions/
│   ├── benefit/earned_income_disregard/rate.yaml   # 75%
│   ├── eligibility/
│   │   ├── earned_income_disregard/rate.yaml       # 1/3
│   │   └── flat_disregard/amount.yaml              # $30
│   └── work_expense/amount.yaml                    # $90
├── resources/
│   ├── limit/at_application/amount.yaml            # $1,000
│   ├── limit/while_receiving/amount.yaml           # $10,000
│   └── vehicle_exemption/amount.yaml               # $20,000
└── standard_of_need/
    ├── amount.yaml                                 # $155-$835 (sizes 1-10)
    └── max_unit_size.yaml                          # 10

Variables (12 files)

policyengine_us/variables/gov/states/in/fssa/tanf/
├── eligibility/
│   ├── in_tanf_countable_income_eligible.py        # Countable income test
│   ├── in_tanf_eligible.py                         # Overall eligibility
│   ├── in_tanf_income_eligible.py                  # Combined income tests
│   ├── in_tanf_payment_eligible.py                 # Payment income test
│   └── in_tanf_resources_eligible.py               # Resource test
├── income/
│   ├── in_tanf_countable_earned_income.py          # 75% disregard
│   ├── in_tanf_countable_earned_income_for_eligibility.py  # $90, $30, 1/3
│   ├── in_tanf_countable_income_for_eligibility.py # Total for eligibility
│   └── in_tanf_countable_income_for_payment.py     # Total for payment
├── resources/
│   └── in_tanf_countable_resources.py              # Asset calculation
├── in_tanf_payment_standard.py                     # Standard of need
└── in_tanf.py                                      # Main benefit

Tests (13 files, 68 test cases)

policyengine_us/tests/policy/baseline/gov/states/in/fssa/tanf/
├── benefit/in_tanf_payment_standard.yaml (7 tests)
├── eligibility/ (21 tests)
├── income/ (14 tests)
├── resources/ (13 tests)
├── in_tanf.yaml (6 tests)
└── integration.yaml (7 tests)

---

Example Calculations

Family of 3 with Earned Income

Household: Single parent with 2 children
Income: $400/month earned income

Eligibility Test:
  $400 - $90 (work expense) = $310
  $310 - $30 (flat) = $280
  $280 × 0.67 = $187.60 countable
  $187.60 < $320 (standard of need) → PASS

Payment Test:
  $400 × 0.25 = $100 countable
  $100 < $320 → PASS

Benefit: $320 - $100 = $220/month

Two-Earner Household (Demonstrating Per-Earner $90)

Household: Family of 3, both parents work
Income: $200/month each ($400 total)

Eligibility Test:
  Person 1: $200 - $90 = $110
  Person 2: $200 - $90 = $110
  Unit total: $220 - $30 = $190 → $190 × 0.67 = $127.30 countable
  
Benefit: $320 - $100 = $220/month

Key: Two earners get $180 total work expense vs $90 for single earner.

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Testing & Verification

Test Results

✅ All 68 tests passing
   - 7 integration tests  
   - 61 unit tests
   - 0 failures

How to Run

policyengine-core test policyengine_us/tests/policy/baseline/gov/states/in/fssa/tanf/ -c policyengine_us

---

Implementation Highlights

Key Features

• ✅ Standard of need for all family sizes (1-10)
• ✅ Two different disregard sets (eligibility vs payment)
• ✅ Per-earner work expense ($90)
• ✅ Per-unit flat + 1/3 disregards
• ✅ Two-tier income eligibility (countable + payment tests)
• ✅ Resource limits with vehicle exemption
• ✅ Proper vectorization throughout

Design Decisions

1. Dual Disregard Sets: Eligibility uses $90 + $30 + 1/3; Payment uses 75%

   • More complex than Ohio (single disregard)
   • Similar complexity to PA

2. Per-Earner vs Per-Unit: $90 is per earner; $30 and 1/3 are per unit

   • Critical for multi-earner households
   • Verified with test cases

3. 4-Month Limit Simplification: $30 and 1/3 disregards technically only apply for first 4 months

   • Simplified: always applies (cannot track benefit history)

4. Post-2023 Reform: Payment standard = 100% of standard of need

   • Previously 50%

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References

Official Sources

• IC 12-14-2-5 - Benefit calculation
• 470 IAC 10.3-4 - Fiscal eligibility
• 470 IAC 10.3-4-4 - Income deductions

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Branch Information

Branch: indiana-tanf-implementation
Base: master
Status: ✅ All formulas verified, 68 tests passing

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Implementation by: @hua7450
Issue: #6868
Ready for: Code review and testing feedback

🤖 Generated with Claude Code

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 100.00%. Comparing base (8272414) to head (5e97ffd).
⚠️ Report is 27 commits behind head on master.

Additional details and impacted files

@@            Coverage Diff             @@
##            master     #6853    +/-   ##
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  Coverage   100.00%   100.00%            
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  Files            1        12    +11     
  Lines           16       160   +144     
==========================================
+ Hits            16       160   +144     

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

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