Medicare may deny coverage for inpatient rehabilitation facility (IRF) care if the patient's medical documentation fails to satisfy strict coverage criteria, such as proving the necessity of intensive, multidisciplinary therapy requiring at least three hours of care per day or active physician supervision. Denials frequently occur if medical records do not clearly demonstrate reasonable expectation of measurable functional improvement, or if the patient's condition can be safely treated at a lower, less intensive level of care like a skilled nursing facility.