Implement Idaho TANF

[hua7450]

Summary

Implements Idaho Temporary Assistance for Families in Idaho (TAFI) program.

Closes #7043

Regulatory Authority

IDAPA 16.03.08 - Temporary Assistance for Families in Idaho (TAFI)

• Primary Legal Authority: IDAPA 16.03.08
• Administering Agency: Idaho Department of Health and Welfare
• Effective Date: April 1, 2016

Income Eligibility Tests

Idaho TAFI uses a benefit-based eligibility determination. Eligibility is determined through the benefit calculation - if the calculated grant standard is positive, the family is income eligible.

Source: IDAPA 16.03.08.248-252

Income Deductions & Exemptions

Earned Income (60% Counted)

For families with earned income, 60% of gross earned income is subtracted from the work incentive table amount.

"For eligible families with earned income, an amount is calculated by subtracting sixty percent (60%) of gross earned income..."

Source: IDAPA 16.03.08.252

Unearned Income (100% Counted)

100% of unearned income is counted against benefits.

Source: IDAPA 16.03.08.250

Income Standards (Work Incentive Table)

Household Size	Monthly Amount
1	$309
2	$309
3	$389
4	$469
5	$547
6	$628
7	$708
8	$787
9	$867
10	$947
11+	$947 + $80 per additional person

Source: IDAPA 16.03.08.251

Benefit Calculation

# With earned income: use work incentive table
# Without earned income: use maximum grant ($309)
base = where(countable_earned > 0, work_incentive - countable_earned, maximum_grant)
grant_standard = max(base - countable_unearned, 0)
benefit = min(grant_standard, maximum_grant)

Source: IDAPA 16.03.08.248-252

Resource Limit

$5,000 maximum countable resources.

Source: IDAPA 16.03.08.200

Files Added

Parameters (6 files)

policyengine_us/parameters/gov/states/id/tafi/
├── income/
│   └── earned/
│       └── countable_rate.yaml      # 60% counted
├── resources/
│   └── limit.yaml                   # $5,000
├── work_incentive_table/
│   ├── additional_person.yaml       # $80 per person over 10
│   ├── amount.yaml                  # Table by size 1-10
│   └── max_size.yaml                # 10
└── maximum_grant.yaml               # $309

Variables (7 files)

policyengine_us/variables/gov/states/id/tafi/
├── id_tafi.py                           # Final benefit
├── eligibility/
│   ├── id_tafi_eligible.py              # Combined eligibility
│   └── id_tafi_resources_eligible.py    # Resource test
└── income/
    ├── id_tafi_countable_earned_income.py   # 60% of gross earned
    ├── id_tafi_countable_unearned_income.py # 100% of unearned
    ├── id_tafi_grant_standard.py            # Grant calculation
    └── id_tafi_work_incentive_amount.py     # Table lookup

Tests (8 files, 42 test cases)

policyengine_us/tests/policy/baseline/gov/states/id/tafi/
├── id_tafi.yaml (4 cases)
├── id_tafi_countable_earned_income.yaml (6 cases)
├── id_tafi_countable_unearned_income.yaml (5 cases)
├── id_tafi_eligible.yaml (9 cases)
├── id_tafi_grant_standard.yaml (2 cases)
├── id_tafi_resources_eligible.yaml (5 cases)
├── id_tafi_work_incentive_amount.yaml (4 cases)
└── integration.yaml (7 cases)

Example Calculations

Example 1: Family of 3, No Income

• No earned income → use Maximum Grant path
• Grant = $309

Example 2: Family of 3, $500 Earned Income

• Work Incentive Table: $389
• Countable earned: $500 × 0.60 = $300
• Grant = min($389 - $300, $309) = $89

Example 3: Family of 4, $400 Earned + $100 Unearned

• Work Incentive Table: $469
• Countable earned: $400 × 0.60 = $240
• Grant = min($469 - $240 - $100, $309) = $129

Implementation Notes

Not Implemented (by design)

Rule	Section	Reason
$10 minimum threshold	254	Grants < $10 not paid - intentionally omitted
Rounding to next lowest dollar	252	Minor impact - intentionally omitted
Self-employment 50% expense deduction	231	Future enhancement - currently uses gross self-employment income
$50 school attendance penalty	142	Requires additional input variable
$50 work activity penalty	169	Requires additional input variable
24-month time limit	101	Cannot simulate (single-period limitation)
Paternity establishment penalty	151	Cannot simulate (time-based)

Key Implementation Decisions

1. Folder named tafi - Uses Idaho's official program name
2. Simplified implementation - Uses federal baseline for demographic and immigration eligibility
3. Benefit-based eligibility - Income eligibility determined via grant_standard > 0
4. Flat maximum grant - Idaho's $309 max applies regardless of family size
5. Historical values unchanged - $309 benefit level has been frozen since late 1990s

References

• IDAPA 16.03.08 - Full Rule
• Idaho Department of Health and Welfare - About TAFI

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[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 100.00%. Comparing base (5900c85) to head (2cb95c1).
⚠️ Report is 2 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff            @@
##              main     #7044   +/-   ##
=========================================
  Coverage   100.00%   100.00%           
=========================================
  Files            6         7    +1     
  Lines           81        97   +16     
=========================================
+ Hits            81        97   +16     

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

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[PavelMakarchuk]

PR Review

🟢 Summary: APPROVED

The Idaho TAFI implementation is high quality and ready for merge. All 42 tests pass, regulatory requirements are correctly implemented, and code follows PolicyEngine standards.

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✅ Validation Results

Check	Result	Notes
Regulatory Accuracy	PASSED	All values match IDAPA 16.03.08
Reference Quality	PASSED	All parameters have references with section numbers
Code Patterns	PASSED	No hard-coded values, proper vectorization
Test Coverage	GOOD	42 tests, comprehensive scenarios
CI Status	Failing	uv.lock freshness (merge conflict)

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🔴 Critical (Must Fix)

None - No critical issues found.

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🟡 Should Address (Minor)

1. CI Failure: uv.lock freshness check failing. Resolve merge conflict:

   git fetch origin && git merge origin/main
   git checkout --theirs uv.lock && uv lock --upgrade

2. Reference Source: Parameters use Cornell Law (secondary aggregator). Consider adding official Idaho adminrules source as secondary reference for traceability (optional).

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🟢 Suggestions (Optional)

1. Work Incentive Table Tests: Currently tests sizes 1-6, 10, 11. Consider adding sizes 7, 8, 9 for completeness.

2. Test Comments: Some calculation comments could be more explicit about intermediate steps (e.g., "30" in test comment could clarify it's 60% of $50).

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Verification Summary

Key Parameter Values Verified:

Parameter	Value	Source
Maximum Grant	$309	IDAPA 16.03.08.248
Earned Income Countable	60%	IDAPA 16.03.08.252
Resource Limit	$5,000	IDAPA 16.03.08.200
Work Incentive (Size 3)	$389	IDAPA 16.03.08.251

Manual Calculation Verified (Case 4):

• Gross earned: $400/month
• Countable earned: $400 × 0.60 = $240
• Unearned (child support): $100
• Work incentive (size 4): $469
• Grant: $469 - $240 - $100 = $129 ✓

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Code Quality Highlights

• ✅ Uses adds for simple aggregation (id_tafi_countable_unearned_income)
• ✅ Uses add() > 0 pattern for immigration check
• ✅ Uses where() and max_() for vectorization
• ✅ Uses period.this_year for stock variables (assets, household size)
• ✅ All values parameterized (no hard-coded numbers)
• ✅ Proper tuple format for multiple references

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Next Steps

1. Resolve uv.lock merge conflict (required for CI)
2. Address suggestions if desired (optional)

To auto-fix issues: /fix-pr 7044

🤖 Generated with Claude Code