has_medicaid_health_coverage_at_interview maps NOW_MCAID, which includes CHIP and other means-tested coverage #1412

Problem

_fill_health_coverage_inputs in packages/microcosm-build/src/microcosm/build/us_runtime/cps_carried.py maps has_medicaid_health_coverage_at_interview from CPS ASEC NOW_MCAID. NOW_MCAID is a recode: the union of NOW_CAID (Medicaid), NOW_PCHIP (CHIP) and NOW_OTHMT (other means-tested coverage). So the "Medicaid" input also holds CHIP and other means-tested reporters, and NOW_OTHMT is counted a second time through has_other_means_tested_health_coverage_at_interview.

In policyengine-us, has_medicaid_health_coverage_at_interview is on the CHIP disqualifying-coverage list (gov.hhs.chip.disqualifying_health_coverage). A person who reports CHIP at interview therefore fails the CHIP no-other-coverage test: in the 2024 default data, all 400 CHIP-reporter records (956,895 weighted) do. For example, a New Jersey child at 250% FPL with the flag set gets no CHIP.

Found during review of PolicyEngine/policyengine-us#10371 (record counts in the default data: 10,622 NOW_CAID, 400 NOW_PCHIP and 159 NOW_OTHMT). That PR's own effect does not depend on it.

Proposed fix

Map has_medicaid_health_coverage_at_interview from NOW_CAID alone. If CHIP at interview is wanted as an input, carry NOW_PCHIP to a separate CHIP flag that the CHIP coverage test does not read. Check the Medicaid enrollment and take-up calibration that may read the current flag (medicaid_take_up.py, #720).

Related

• Pooled ASEC 2022/2023 vintages lack the NOW_* coverage recodes: reported Medicaid at interview thins to 24.6M vs ~58M survey under 65 on the certified artifact #720 (NOW_* recodes missing from pooled vintages).
• Apply the CHIP no-other-coverage test to pregnancy pathways in every state policyengine-us#10371, CHIP disqualifying-coverage list includes public coverage that SSA 2110(b)(1)(C) does not exclude policyengine-us#10475 (the CHIP coverage list), Reconcile reported Medicaid coverage when modeled eligibility is false policyengine-us#8495 and Add CHIP current-coverage input for CPS/API partner data policyengine-us#8577.