Synthetic demonstration data — State of Cascadia is fictional. Methodology is real.
Cross-system Medicaid reconciliation · State of Cascadia — mid-MMIS transition

Every system passes its own audit. The seams don’t.

Three systems — county eligibility, a claims platform midway through a vendor transition, and a monthly Medicare COB file — each internally consistent. Reconciled against each other, they surface 41,463 affected members and $337.7M in estimated exposure.

41,463
Members affected
$337.7M
Estimated exposure
6
Break classes
3
Systems reconciled
CBES · internally consistent
MMIS · internally consistent
⚠ Cross-system · 6 break classes detected

Exposure by break class

Estimated dollars at risk per discrepancy class — click a bar for the member-level evidence.

The six break classes

Each one invisible to single-system review. Each one found by reconciling the seams.

Transition Orphans

Members carried onto the Meridian claims platform during the vendor cutover and still receiving capitation, with no active eligibility span behind them in CBES.

27,943 members$155.1M
Audit finding — capitation recoupment / CMS-64 exposure

Dual/COB Mismatch

Members flagged dual-eligible in CBES who are missing from the Medicare COB file, or present with effective dates that don't reconcile — Medicaid paying primary where Medicare should be.

4,517 members$101.6M
Federal disallowance — Medicare primary payer

Aid Category Conflicts

CBES and MMIS carry different aid categories for the same member and span, so capitation pays from the wrong rate cell. Small dollars per member, huge member counts.

18,922 members$34.1M
Capitation rate-cell error — recoupment / rate certification

Point-in-Time Reconstruction Failure

Members whose current record looks compliant, but whose span history contains overlapping or retroactively edited spans with no audit trail — the state cannot reproduce what eligibility was on a given past date.

12,081 members$20.2M
Federal reporting / audit reconstruction failure

Eligibility Span Drift

Member exists in both systems, but enrollment spans disagree by more than 30 days — MMIS keeps paying past the CBES termination, or starts paying before approval.

8,876 members$19.6M
Improper payment rate (PERM) exposure

County Transfer Gaps

Member moved counties; the old county terminated, the new county's span started late, and MMIS kept paying under the stale county code the whole time.

3,164 members$7.1M
Improper payment — county attribution error

Members can appear in more than one break class; the headline figure of 41,463 counts unique members.