The method by which the amount of costs payable by one party to another, or payable by a client to his solicitor, is determined by an officer of the court. Before the introduction of the Civil Procedure Rules in 1999, this was called taxation of costs. Assessments may be summary or detailed. In a summary assessment, the court determines the amount payable immediately at the end of the hearing. In this instance, the court can call for whatever evidence is available at the time (e.g. brief fee) to determine the amount. This is the preferred method of assessment in fast track trials. Summary assessment can only be carried out by the judge who heard the case at the time. In contrast, a detailed assessment involves the quantification of costs to a costs officer, who considers the amount at some stage after the hearing. Detailed assessments are mostly carried out by district judges in the county courts but there is a dedicated office, the Supreme Court Costs Office, for the High Court.