The CMS Hospital Readmissions Reduction Program reduces all Medicare inpatient payments by up to 3% for hospitals with excess 30-day readmissions across six conditions. That makes readmission measurement one of the few places where a quality metric maps directly onto a payment mechanism — and where getting the analysis right has real money attached.
Case 01 asks whether a modifiable intervention actually causes lower readmissions, or only appears to because healthier, better-insured patients are the ones receiving it. Case 02 asks whether a hospital's excess-readmission flag reflects something specific to that hospital at all, once volume and measurable quality performance are accounted for.
Does follow-up care actually prevent readmissions — or does it just look that way?
Five-hospital system, FY2023, 2,500 discharges. A naïve comparison says 7-day post-discharge follow-up cuts readmission by 9.2 points. After correcting for who actually receives follow-up, the real effect is meaningfully smaller — and still worth acting on.
Is a hospital's excess-readmission flag a real signal, or just volume?
CMS HRRP FY2026 merged with the Unplanned Hospital Visits file — 2,477 hospitals, 8,037 hospital-condition records. Once discharge volume and eight quality measures enter the model, most of the apparent hospital effect disappears. Then the model is applied to one real hospital.