Backdate Indiana TANF parameters to program inception

[hua7450]

Summary

Backdates Indiana TANF parameters to 1997 program inception, corrects vehicle exemption historical values and while-receiving resource limit effective date, and differentiates applicant vs. recipient income deductions with 4-month earned income disregard limit.

Closes #7498

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Parameter Changes

Backdated to 1997-10-01 (program inception)

• Standard of need (sizes 1-10): $139-$697 (AFDC-era levels, frozen until 2023)
• Max unit size: 10
• Continuing eligibility FPG rate: 100%
• Resource limit at application: $1,000
• Resource limit while receiving: $1,500
• Work expense deduction: $90/earner
• Flat disregard: $30
• Earned income disregard (eligibility): 33%
• Earned income disregard (benefit): 75%

Source: 470 IAC 10.3-4 | IC 12-14 | Indiana DCS Unlicensed Relative Placements (pre-2023 standard of need)

Corrected Values

Parameter	Before	After	Source
While-receiving resource limit date	2023-07-01	2022-07-01	P.L.83-2022, SEC.2
Vehicle exemption at 1997	$20,000	$1,000	WRD Table L9

Source: FSSA DFR Chapter 3000, Section 3005.10.00 | WRD Table L8 ($1,500 as of July 1998)

Added Vehicle Exemption History

Date	Amount	Source
1997-10-01	$1,000	WRD Table L9
1999-07-01	$5,000	WRD Table L9
2021-07-01	$10,000	WRD Table L9
2022-07-01	$20,000	FSSA DFR Ch 2600, Sec 2615.60.15

Source: IC 12-14-2-1(b)(2) | FSSA DFR Chapter 2600 | Urban Institute WRD

New Parameter

• earned_income_disregard/months.yaml: 4-month duration for the 1/3 disregard

Source: 470 IAC 10.3-4-4(c)(2) | FSSA DFR Chapter 3400, Section 3450.25.00

Reference Improvements

• Added secondary references (FSSA DFR Chapters 2600, 3000, 3400) to 9 parameter files
• Added IAC subsection paths for specificity
• Added WRD Table L8 reference for $1,500 while-receiving limit
• Changed breakdown label from "Household size" to "Assistance unit size"

Source: FSSA DFR Chapter 3000 | FSSA DFR Chapter 3400 | FSSA DFR Chapter 2600

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Formula Change

in_tanf_countable_earned_income_for_eligibility.py

• Before: Always applied $90 + $30 + 1/3 disregard to everyone
• After: Differentiates applicants vs. recipients using is_tanf_enrolled:
  • Applicants: $90 work expense only
  • Enrolled (months 1-4): $90 + $30 + 1/3 disregard
  • Enrolled (months 5-12): $90 + $30 only (1/3 expires)
• Uses calendar month as proxy for benefit duration

Source: 470 IAC 10.3-4-4 | FSSA DFR Chapter 3400, Section 3450.20.00-3450.25.00

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Tests

• 111 total tests pass
• New test cases cover: enrolled phase 1 & 2, applicants, annual periods, historical parameters (1997, 2018), resource eligibility, edge cases

Test Plan

• All 111 tests pass
• make format clean
• CI checks

Generated with Claude Code

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 100.00%. Comparing base (55a0045) to head (7787f94).
⚠️ Report is 20 commits behind head on main.

Additional details and impacted files

@@             Coverage Diff             @@
##             main     #7499      +/-   ##
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+ Coverage   97.82%   100.00%   +2.17%     
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  Files           3         1       -2     
  Lines          92        21      -71     
  Branches        2         0       -2     
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- Hits           90        21      -69     
+ Misses          1         0       -1     
+ Partials        1         0       -1     

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

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