Final answer:
The classification model used to adjust for case mix in Medicare's prospective payment system for skilled nursing facilities is the Resource Utilization Groups (RUGs) model.
Step-by-step explanation:
The classification model used to adjust for case mix in Medicare's prospective payment system for skilled nursing facilities is the Resource Utilization Groups (RUGs) model. The RUGs model categorizes patients based on their clinical characteristics and care needs, and assigns a payment group to each patient. This helps Medicare to allocate reimbursements appropriately based on the complexity and intensity of care required for each patient.