In 1999, the Centers for Medicare & Medicaid Services revised the Conditions of Participation, often referred to as COP. These are rules that home health agencies must meet to participate in the Medicare program. One of the new rules required that each patient receive a patient-specific comprehensive assessment that identifies the patient's need for home care and meets his or her medical, nursing, rehabilitative, social, and discharge planning needs. OASIS items are part of the comprehensive assessment when evaluating adult non-maternity Medicare or Medicaid patients who are receiving skilled care. A comprehensive assessment is required for patients receiving skilled care reimbursed by other payer sources or personal care exclusively. Patients receiving only homemaker, or chore services are excluded from the comprehensive assessment requirement.