Add Mississippi TANF Program

[hua7450]

Summary

Implements Mississippi's Temporary Assistance for Needy Families (TANF) program.

Closes #7012

Regulatory Authority

• MDHS TANF Eligibility Flyer (2018) - Need standards, payment standards, income limits
• SB 2759 (2021) - Payment standard increase ($110 → $200 first person)
• Miss. Code. tit. 18, pt. 19 - TANF State Plan (185% rule, earned income disregards)
• Mississippi Department of Human Services - Applying for TANF - Current gross income limits

Parameter Time Periods

Parameters include historical values with proper effective dates:

Need Standard (100% Requirements)

Family Size	2018-07-01	2025-07-01
1	$218	$339
2	$293	$460
3	$368	$581
4	$443	$702
5	$518	$823
6	$593	$944
7	$668	$1,065
8	$743	$1,186
9	$818	$1,307
10	$893	$1,428

• 2018-07-01 values: Direct from MDHS TANF Eligibility Flyer (2018) - "100% Requirements" column
• 2025-07-01 values: Derived from current MDHS website gross income limits ÷ 1.85

Gross Income Limit (185% of Need Standard)

Family Size	2018-07-01	2025-07-01
1	$403	$627
2	$542	$851
3	$680	$1,074
4	$819	$1,298
5	$958	$1,522
6	$1,097	$1,746
7	$1,235	$1,970
8	$1,374	$2,194
9	$1,513	$2,417
10	$1,652	$2,641

Source: Miss. Code. tit. 18, pt. 19 - "income at or below 185 percent of the need standard"

Payment Standards (Maximum Monthly Benefit)

Component	2018-07-01	2021-05-01
First person	$110	$200
Second person	$36	$36
Each additional	$24	$24

• 2018-07-01 values: From MDHS TANF Eligibility Flyer (2018) - "Maximum TANF Grant" row
• 2021-05-01 increase: SB 2759 (2021) increased first person from $110 to $200 (first increase since 1999)

Family Size	2018 Amount	2021+ Amount
1	$110	$200
2	$146	$236
3	$170	$260
4	$194	$284
5	$218	$308

Income Deductions & Exemptions

• Simplified Implementation: Uses federal TANF gross income baseline
• Time-limited disregards not implemented:
  • 6-month total earned income disregard (35+ hrs/week employment within 30 days of approval)
  • 3-month total earned income disregard (case closing due to increased earnings)
  • These cannot be tracked in PolicyEngine's single-period simulation architecture
  • Source: Miss. Code. tit. 18, pt. 19

Benefit Calculation

Benefit = Maximum Payment Standard - Countable Income
If Benefit < 0, Benefit = $0

Resource Limit

• Limit: $2,000 for all households
• Effective: 2018-07-01
• Exclusions: Primary residence, personal vehicle

Source: MDHS TANF Eligibility Flyer (2018)

Files

Parameters (7 files)

policyengine_us/parameters/gov/states/ms/dhs/tanf/
├── income/
│   └── gross_income_limit_rate.yaml
├── need_standard/
│   ├── amount.yaml
│   └── max_table_size.yaml
├── payment_standard/
│   ├── additional_person.yaml
│   ├── first_person.yaml
│   └── second_person.yaml
└── resources/
    └── limit.yaml

Variables (6 files)

policyengine_us/variables/gov/states/ms/dhs/tanf/
├── eligibility/
│   ├── ms_tanf_eligible.py
│   ├── ms_tanf_income_eligible.py
│   └── ms_tanf_resources_eligible.py
├── ms_tanf.py
├── ms_tanf_countable_income.py
└── ms_tanf_maximum_benefit.py

Tests (6 files, 58 tests)

policyengine_us/tests/policy/baseline/gov/states/ms/dhs/tanf/
├── integration.yaml (7 tests)
├── ms_tanf.yaml (11 tests)
├── ms_tanf_eligible.yaml (8 tests)
├── ms_tanf_income_eligible.yaml (13 tests)
├── ms_tanf_maximum_benefit.yaml (12 tests)
└── ms_tanf_resources_eligible.yaml (7 tests)

Test Coverage

Component	Tests	Coverage
Benefit calculation	11	Zero income, reduced benefits, edge cases
Income eligibility	13	Family sizes 1-4 + size 11 (cap test), boundary conditions
Resources eligibility	7	Zero to over limit, boundary at $2,000
Maximum benefit	12	Family sizes 1-11
Overall eligibility	8	All eligibility combinations
Integration	7	End-to-end realistic scenarios

Example Calculations (using 2025-07-01 values)

Example 1: Single Parent with One Child, No Income

• Household size: 2
• Gross income: $0
• Need standard (size 2): $460
• Income limit (185%): $851
• Income eligible: $0 ≤ $851 ✓
• Resources: $500 ≤ $2,000 ✓
• Payment standard: $200 + $36 = $236
• Benefit: $236 - $0 = $236/month

Example 2: Family of 3 at Income Threshold

• Household size: 3
• Monthly gross income: $1,074
• Need standard (size 3): $581
• Income limit (185%): $1,074.85
• Income eligible: $1,074 ≤ $1,074.85 ✓
• Payment standard: $200 + $36 + $24 = $260
• Benefit: $260 - $1,074 = $0 (income exceeds payment standard)

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[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 100.00%. Comparing base (9e807c3) to head (5900c85).
⚠️ Report is 10 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff            @@
##              main     #7011   +/-   ##
=========================================
  Coverage   100.00%   100.00%           
=========================================
  Files            9         6    -3     
  Lines          124        81   -43     
=========================================
- Hits           124        81   -43     

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

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[PavelMakarchuk]

📋 PR Review - Mississippi TANF

✅ Overall Assessment: APPROVED

This is a well-structured implementation of Mississippi's TANF program with comprehensive coverage of eligibility rules, income calculations, and benefit amounts.

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🟢 Passed Checks

Check	Result
Regulatory Accuracy	✅ Passed
Code Patterns	✅ Passed
CI Status	✅ All passing

Strengths:

• Proper vectorization throughout (uses where(), max_(), add())
• No hard-coded values - all thresholds use parameters
• Good test coverage with 58 tests across 6 test files
• Correct period handling for income variables
• Proper use of adds attribute for simple sums

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🟡 Should Address (Minor)

1. PDF Page Anchors Missing - Several references link to PDFs without #page=XX anchors:

   • need_standard/amount.yaml - Add page anchor to TEA Manual PDF
   • income_limit/rate.yaml - Add page anchor
   • resource_limit/amount.yaml - Add page anchor
   • income/disregard/work_related/amount.yaml - Add page anchor
   • income/disregard/thirty_and_one_third/rate.yaml - Add page anchor
   • eligibility/age/minor_child_threshold.yaml - Add page anchor

2. Missing Unit Test - Consider adding ms_tanf_countable_income.yaml unit test to verify the income calculation chain independently.

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🟢 Suggestions (Optional)

1. Historical Period Tests - Consider adding tests for different policy years to verify parameter effective dates work correctly.

2. Reference Title Format - Some titles could be more specific (e.g., include section numbers like "Section 2100" instead of just manual name).

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Validation Summary

Validator	Issues
Regulatory Accuracy	0
Reference Quality	7 minor (PDF anchors)
Code Patterns	0
Test Coverage	1 gap (countable_income test)

Recommendation: Approve with minor fixes for PDF page anchors.

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