“A deposition is testimony taken before trial, under oath, subject to cross-examination, and preserved in writing. The major advantage of a deposition over any other discovery device is that oral examination permits more effective questioning. If the deponent’s answers are incomplete or nonresponsive, the examiner can pursue the point with follow-up questions. Also, the deponent’s credibility and memory can be tested by questions as to peripheral matters that tend to confirm or disprove earlier answers. Finally, there is a much better chance of getting spontaneous admissions than with other discovery devices (e.g., interrogatories, where the answers are usually prepared by opposing counsel). Another advantage is that depositions permit the examiner to determine the impression the witness is likely to make on the jury if the case goes to trial; i.e., whether sincere, sympathetic, believable, etc. Other forms of discovery produce only written responses that shed little light on the witness’ credibility and demeanor. Depositions can usually be set on 10 or 15 days’ notice to the opposing party. (However, depositions generally should not be noticed until all parties have appeared so the depositions will count as each party’s opportunity for a deposition and thus cannot be taken again absent consent or leave of court) Documents can be inspected and answers can be obtained (orally) at the time of the deposition. This is far quicker than other discovery devices. The examiner has the option of recording the deposition by audio or video technology, which often provides a far greater impact in jury trials than any other form of discovery.”
[California Practice Guide: Civil Procedure Before Trial [citations to primary sources omitted]]
