Evaluation of the necessity, appropriateness, and efficiency of the use of health care services, procedures, and facilities. In a hospital, this includes review of the appropriateness of admissions, services ordered and provided, length of a stay, and discharge practices, both on a concurrent and retrospective basis. Utilization review can be done by a peer review group, or a public agency. UR is a method of tracking, reviewing and rendering opinions regarding care provided to patients. Usually UR involves the use of protocols, benchmarks or data with which to compare specific cases to an aggregate set of cases. Those cases falling outside the protocols or range of data are reviewed individually. Managed care organizations will sometimes refuse to reimburse or pay for services which do not meet their own sets of UR standards. UR involves the review of patient records and patient bills primarily but may also include telephone conversations with providers. The practices of pre-certification, re-certification, retrospective review and concurrent review all describe UR methods. UR is one of the primary tools utilized by IDS, MCO and health plans to control over-utilization, reduce costs and manage care.