Fix MN MFIP transitional standard to exclude food portion (SNAP equivalent)

[hua7450]

Summary

Fixes #7444 — Updates MN MFIP transitional standard parameter to use cash-only amounts, excluding the food portion (SNAP equivalent) to avoid double-counting food assistance.

Background

MFIP is Minnesota's combined cash+food TANF program, operating under a USDA waiver. Recipients receive food assistance through MFIP instead of separate SNAP. The previous parameter included both the cash and food portions of the transitional standard.

Since PolicyEngine already models SNAP federally for all states, MFIP-eligible households were receiving:

1. MFIP benefit (including food portion) +
2. Federal SNAP benefit

This caused double-counting of food assistance. The MFIP food portion amounts are also ~15–17% lower than federal SNAP maximum allotments, making the double-count even more distortionary.

Regulatory Authority

• MN Statute 142G.17, Subd. 5 — Transitional Standard
• MN House Research — MFIP Overview, p.17 — Cash/food breakdown table
• MN House Research — MFIP Grants Calculation — Historical cash amounts
• MN DHS Combined Manual — MFIP/DWP Assistance Standards

Cash Portion by Family Size

Values verified against pap_mfip.pdf#page=17:

Family Size	Full TS (before)	Cash Portion (after)	Food Portion (excluded)
1	$661	$419	$242
2	$1,087	$642	$445
3	$1,394	$756	$638
4	$1,675	$861	$814
5	$1,933	$952	$981
6	$2,238	$1,043	$1,195
7	$2,435	$1,134	$1,301
8	$2,695	$1,214	$1,481
9	$2,951	$1,290	$1,661
10	$3,201	$1,357	$1,844
Each add'l	$249	$64	$185

Effective October 1, 2024

Historical (pre-Oct 2021)

Cash portion was frozen at AFDC levels from 1997 until October 2021 (verified from mfipgrant.pdf#page=3).

Approach & Trade-offs

Approach chosen: Replace the transitional standard parameter with cash-only amounts. The Family Wage Level (FWL = TS × 1.1) now uses cash-only TS for eligibility testing.

Trade-off: In regulation, the FWL uses the full transitional standard (cash + food). Using cash-only TS makes the eligibility threshold slightly stricter than real life. This was accepted as the simpler approach since:

• SNAP eligibility handles the food assistance side independently
• The alternative (maintaining both full TS and cash-only parameters) adds complexity for marginal accuracy gain
• Minnesota is the only state with this combined cash+food TANF structure

Changes

Parameters

• transitional_standard/amount.yaml — Cash-only amounts for all family sizes (1–10) across 3 date ranges
• transitional_standard/additional_person.yaml — Cash-only increment for families >10

Variables

• mn_mfip.py — Added NOTE explaining cash-only modeling
• mn_mfip_transitional_standard.py — Updated label to "(cash portion)", added NOTE

Tests

• All 50 MFIP tests updated and passing
• Redesigned mn_mfip_income_eligible boundary test (Case 2) for lower FWL threshold
• Updated all integration test calculations with cash-only values

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 100.00%. Comparing base (55a0045) to head (7abc88d).
⚠️ Report is 15 commits behind head on main.

Additional details and impacted files

@@             Coverage Diff             @@
##             main     #7512      +/-   ##
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+ Coverage   97.82%   100.00%   +2.17%     
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  Files           3         2       -1     
  Lines          92        34      -58     
  Branches        2         0       -2     
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- Hits           90        34      -56     
+ Misses          1         0       -1     
+ Partials        1         0       -1     

Flag	Coverage Δ
unittests	100.00% <100.00%> (+2.17%)	⬆️

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