PolicyEngine backdates South Carolina’s EITC into 2015–2017

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Since Nov 14, 2026.

  • #10945 by @MaxGhenis — open

Assessment

Difficulty
2/5
Estimated time
1-3 hours
Newbie friendliness
72/100
Issue type
Bug
Clarity
Clearly specified
Activity status
Active
Tech stack
python
Domain
backend

Research direction

The bug is in the South Carolina EITC parameter values, which currently apply the 20.83% match to tax years 2015–2017. Start with the sc_eitc parameter definition and its existing 2018 rate entry, and with the 2017 test that expects a $0 credit but gets $208.30 and stops before the sc_eitc assertion. Add a zero-rate entry effective from 2015, keep the 2018 rate, then rerun that test and the nearby sc_eitc tests to confirm 2015–2017 return $0.

Written by the indexing model from the issue text.

Description

PolicyEngine backdates South Carolina’s 20.83% earned income tax credit (EITC) match into 2015–2017, before the credit began.

The General Assembly introduced a nonrefundable credit for tax years after 2017 in Act 40 of 2017, section 16. South Carolina’s Department of Revenue confirms the first 20.83% match in the 2018 TC-60.

With a known $1,000 federal EITC and $1,000 of state tax before credits, the 2017 test returned a $208.30 potential credit against an expected $0. The runner stopped before the sc_eitc assertion.

Add a 2015 zero-rate entry to cover modeled tax years 2015–2017 while retaining the rates from 2018 onward.

Dominant language
Python
Stars
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Forks
220
Avg merge
4d 13h
Merged PRs (30d)
291

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