Add Nebraska LB 157 Child Tax Credit reform

[DTrim99]

Summary

Implements Nebraska LB 157 (the "Child Tax Credit Act") as a contributed reform.

Bill Details

• Bill: LB 157
• Sponsor: Conrad, 46
• Introduced: January 13, 2025

Key Features

Credit Amount

• $1,000 per qualifying child, fully refundable

Qualifying Child

• Age 6 or younger at end of taxable year
• Claimed as dependent on federal return
• Has SSN or ITIN

Phase-out Structure

Credit phases out at 5% per income increment above thresholds:

Filing Status	Threshold	Increment
Married Filing Jointly	$110,000 AGI	$2,000
Head of Household	$92,500 AGI	$1,500
All Other Filers	$75,000 AGI	$1,000

Effective Date

• Tax years beginning on or after January 1, 2026
• Inflation adjustment starting January 1, 2027 (indexed to same CPI as Nebraska income tax brackets)

Implementation

• Parameters at gov.contrib.states.ne.ctc.lb157
• Reform registers ne_lb157_ctc as a refundable credit in Nebraska's tax system
• 9 unit tests covering various scenarios including phase-out calculations

References

• LB 157 Bill Text

Closes #7510

Test plan

• Unit tests pass for all 9 scenarios
• CI passes

🤖 Generated with Claude Code

[DTrim99]

PR Review: Nebraska LB 157 Child Tax Credit

🟢 Overall Assessment: APPROVE

This is a well-implemented reform with comprehensive test coverage. All CI checks pass and the implementation correctly reflects the bill's provisions.

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✅ What's Good

1. Correct credit structure: $1,000 per qualifying child with proper phase-out
2. Proper phase-out formula: Uses ceiling for increment calculation (np.ceil(excess / increment)) which correctly handles "or fraction thereof" language
3. Good test coverage: 9 tests covering eligibility, phase-out calculations, age boundaries, and reform toggle
4. Correct refundable credit registration: Properly adds to Nebraska's refundable credits list
5. All parameters externalized: No hard-coded values in formulas

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🟡 Should Address

1. Reference URLs point to wrong document ID

All parameter references use DocumentID=55861 but the bill is at DocumentID=58940:

• Current: https://nebraskalegislature.gov/bills/view_bill.php?DocumentID=55861
• Should be: https://nebraskalegislature.gov/bills/view_bill.php?DocumentID=58940

Files affected:

• age_limit.yaml
• amount.yaml
• in_effect.yaml
• phaseout/increment.yaml
• phaseout/rate.yaml
• phaseout/threshold.yaml
• ne_lb157_ctc.py (variable references)

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🟢 Suggestions

1. Consider adding test for zero qualifying children

While the code handles this correctly, an explicit test would document the expected behavior.

2. Consider documenting inflation indexing limitation

The bill includes inflation adjustment starting 2027 (per Section 3(1)), but this is not currently modeled. A comment in the code or parameter file noting this would be helpful.

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Validation Summary

Check	Result
Regulatory Accuracy	✅ Correct per bill text
Reference Quality	🟡 Wrong document ID
Code Patterns	✅ Good
Test Coverage	✅ 9 tests
CI Status	✅ All passing

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Verified Against Bill

Provision	Bill	Implementation
Credit amount	$1,000/child	✅ amount.yaml
Age limit	≤6 years	✅ age_limit.yaml
MFJ threshold	$110,000	✅ phaseout/threshold.yaml
MFJ increment	$2,000	✅ phaseout/increment.yaml
HOH threshold	$92,500	✅ phaseout/threshold.yaml
HOH increment	$1,500	✅ phaseout/increment.yaml
Phase-out rate	5%	✅ phaseout/rate.yaml
Refundable	Yes	✅ Added to refundable credits
Effective date	2026+	✅ Parameters start 2026-01-01

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Next Steps

Fix the reference URLs from DocumentID=55861 to DocumentID=58940, then this is ready to merge.

🤖 Review generated with Claude Code

[DTrim99]

Fixed reference URLs: all parameters and variables now point to the correct DocumentID (58940 instead of 55861).