Utilization management (UM) or utilisation review is the application of managed care techniques, such as prior authorization, to allow payers, particularly health insurance companies, to manage the cost of health care advantages by assessing their appropriateness before they are provided using evidence-based criteria or guidelines. Critics have argued that if insurers use UM criteria to cut costs, it could lead to healthcare rationing through overzealous denial of care, retrospective denial of payment, delays in care, or unexpected financial risks to patients. According to the Institute of Medicine (IOM) Committee on Utilization Management by Third Parties, utilisation management is "a set of techniques used by or on behalf of purchasers of health care benefits to manage health care costs by influencing patient care decision-making through case-by-case assessments of the appropriateness of care prior to its provision" (1989; IOM is now the National Academy of Medicine). Utilization management is synonymous with, or a component of, utilisation review (depending on how the terms are used). The evaluation of the appropriateness and medical necessity of health care services, procedures, and facilities using evidence-based criteria or guidelines and in accordance with the provisions of an applicable health insurance plan is referred to as UM. UM typically addresses new clinical activities or inpatient admissions based on a case analysis. However, this could be related to on-going care, particularly in an inpatient setting. Proactive UM procedures include discharge planning, concurrent planning, pre-certification, and clinical case appeals. It also covers proactive processes such as concurrent clinical reviews and peer reviews, as well as provider, payer, or patient-initiated appeals. Roles, policies, processes, and criteria are all part of a UM programme. UM criteria are medical guidelines that can be developed in-house, purchased from a vendor, or purchased and adapted to meet local needs. McKesson Intermural criteria and MCG are two commonly used UM criteria frameworks (previously known as the Milliman Care Guidelines)