Depositions are also used for strategic reasons. In a courtroom, deposition testimony may be used to impeach witnesses who have contradicted their prior testimony. Sometimes an ill-prepared expert will say one thing at the deposition and another thing at the trial. The attorney then confronts the witness with inconsistent statements to challenge the validity of the testimony. For this reason an expert witness should review the deposition transcript before trial, especially since several months often pass between the deposition and the trial.
Lawyers also use depositions to search for unknown information.
The attorney representing a parent in a child custody case, for example, might depose the child's pediatrician in an attempt to discover as much as possible about the child's behavior and relationship with the parents. The hope is to discover a contradiction, evasion or other fact that would help the attorney prove the case. The answer is generally simple. If a subpoena is duly served upon you according to the North Carolina Rules of Civil Procedure, you are required to appear. The sanctions for noncompliance include contempt of court and fines.