Complete Illinois CCAP copays and provider payment rates

[hua7450]

Summary

This PR extends the existing Illinois Child Care Assistance Program (CCAP) model from eligibility-only coverage to monthly family copayments, maximum base provider rates, and ordinary child care subsidy payments. It also updates countable income, continuing-family income eligibility, immigration treatment, benefit aggregation, and program metadata.

Fixes #9188.

Regulatory authority

The implementation uses the following official Illinois sources:

• IDHS parent copayment schedule effective July 1, 2025
• IDEC parent copayment schedule effective July 1, 2026
• IDHS CCAP Policy 04.02.01, Copayments
• IDHS provider rates effective July 1, 2025
• IDEC provider rates effective July 1, 2026
• IDHS CCAP Policy 06.05.01, Payment Rates
• IDHS non-exempt income policy, exempt income policy, and income guidelines effective July 1, 2026
• IDHS citizenship and funding-source policy

Income eligibility tests

• Retain the 225% FPL limit for new applicants.
• Retain the 275% FPL limit for enrolled families before July 1, 2026.
• Apply the 85% state median income ceiling to enrolled families beginning July 1, 2026. The model does not track the three-month graduated phase-out period.
• Remove qualified immigration status as a program eligibility gate because Illinois authorizes otherwise-eligible non-qualified children with State funds. The existing immigration-status variable remains available for funding classification.
• Test the applicable income limits immediately below, at, and above their boundaries, including the July 2026 transition.

Income deductions and exemptions

The countable-income calculation maps the official non-exempt categories to 12 model inputs, including wages, farm and non-farm self-employment income, rental income, royalty income, dividends, interest, pensions, veterans benefits, unemployment compensation, and workers compensation. It excludes the income categories identified as exempt in Illinois policy, deducts child support paid, and floors countable income at zero.

The model excludes all child earnings as the approved approximation because the data do not identify whether a child is the CCAP applicant. Tests cover adult income, child earnings, child support paid, rental income, royalty income, missing income, and a negative net amount.

Income standards

• Encode every published Table A monthly copayment cell for family sizes 2 through 10, with histories beginning July 1, 2025 and July 1, 2026.
• Derive Table B as 50% of Table A for September through May when every child in care is age 5 through 13, enrolled in school, and approved for less than five hours of daily care.
• Retain the published $0.50 lowest Table B copayment and the $1 ordinary minimum copayment.
• Apply a $1 copayment to qualifying child care workers and a zero copayment to qualifying child-only TANF relative and protective-care cases.
• Clamp copayment lookup below family size 2 to the size-2 table and above family size 10 to the size-10 table because the published schedules contain no other family sizes.

The seasonal test verifies the exact Table A/Table B boundaries: $0.50 in May, $1 in June, $1 in August, and $0.50 in September for the tested lowest-band household.

Benefit calculation

The model classifies each eligible child by four provider types, three county groups, three age groups, and daily care duration. It applies the official 2025 and 2026 maximum base rates for part-day, full-day, full-plus-part-day, and two-full-day care.

For each eligible child, the model:

1. Multiplies the applicable maximum daily rate by nonnegative attending days.
2. Caps monthly pre_subsidy_childcare_expenses at that maximum.
3. Sums capped costs across eligible children.
4. Subtracts one monthly family copayment and floors the subsidy at zero.

The PR publishes the result as monthly il_ccap, adds annual il_child_care_subsidies, and registers the Illinois amount in the federal child care subsidy aggregator.

Requirements coverage

The approved scope contains 25 simulatable requirements. The committed parameters, formulas, and tests cover all 25. Five additional requirements remain tracked as explicit exclusions, for 30 total requirements.

Validation status:

• Structural validation: passed with no escalations.
• Program tests: 120 passed, comprising 119 YAML cases and one Python seasonal-boundary test.
• Final quick diff audit: passed.

Not modeled

• Longitudinal copayment reassessment during the 12-month eligibility period.
• Operational assignment of one family copayment among children and providers.
• Quality and seniority add-ons because the acquired official sources do not publish their amounts.
• Paid personal-leave payments because the model lacks provider leave-use history.
• Separate copayment schedules outside published family sizes 2 through 10; the lookup uses the approved clamp instead.

Historical notes

The modeled payment schedules begin July 1, 2025 and retain the July 1, 2026 histories. Illinois transferred program administration from IDHS to IDEC on July 1, 2026; this PR retains the existing gov.states.il.dhs.ccap path to avoid an unrelated model-tree migration. The current IDEC provider page supplies the current program context.

The ordinary subsidy uses published base provider rates. It does not treat quality, seniority, or paid-leave payments as ordinary child-day reimbursements.

Files added

This commit changes 74 files: 66 added and 8 updated.

• Parameters: 38 files (36 added, 2 updated), including nine dated copayment scales and four provider-rate tables.
• Variables: 19 files (16 added, 3 updated), covering copayments, income, eligibility, provider classifications, payment rates, the subsidy, and aggregation.
• Tests: 15 files (13 added, 2 updated), including 14 YAML files and one Python seasonal-boundary test.
• Metadata and changelog: update policyengine_us/programs.yaml and add one towncrier fragment.