Traditional method of payment for health care services where specific payment is made for specific services rendered. Usually people speak of this in contrast to capitation, DRG or per diem discounted rates, none of which are similar to the traditional fee for service method of reimbursement. Under a fee-for-service payment system, expenditures increase if the fees themselves increase, if more units of service are provided, or if more expensive services are substituted for less expensive ones. This system contrasts with salary, per capita, or other prepayment systems, where the payment to the physician is not changed with the number of services actually used. Payment may be made by an insurance company, the patient or a government programme such as Medicare or Medicaid. With respect to the physicians or other supplier of service, this refers to payment in specific amounts for specific services rendered--as opposed to retainer, salary, or other contract arrangements. In relation to the patient, it refers to payment in specific amounts for specific services received, in contrast to the advance payment of an insurance premium or membership fee for coverage, through which the services or payment to the supplier are provided.