How Interrogatories and Depositions Compare

By Julie Brook, Esq., reprinted with permission from CEB.

August 6, 2021

When deciding whether to use interrogatories or depositions in discovery, there are several things to compare.

Interrogatories have some very clear benefits over depositions:

• Answers to interrogatories can be much more complete than answers to deposition questions.
• Interrogatories are generally less expensive than depositions because they don’t require court reporter fees, transcript costs, or attorney time in traveling to and from the deposition.
• Unlike depositions, interrogatories may inquire not only into the responding party’s present recollection, but also into the collective knowledge available to him or her, including knowledge of his or her agents and attorneys (see Code Civ. Proc., §§ 2017.010–2017.020, 2030.010(b)).

But the opportunity for deliberation between the responding party and their attorney before answering interrogatories is a major downside to interrogatories: Interrogatory answers don’t have the spontaneity of answers to deposition questions, so they don’t allow you to evaluate what kind of witness the responding party will make. In addition, unlike depositions, interrogatories don’t give the opportunity for spontaneous follow-up questions.

It’s this opportunity for spontaneous questions and answers that makes depositions superior to interrogatories for determining what was said in conversations and for eliciting a party’s recollection of an occurrence. Another big advantage of depositions is that they may be used to compel nonparties to give testimony, whereas interrogatories can’t.

Interrogatories have superior qualities, too—they’re usually preferable for identifying relevant documents a party has or knows of and for establishing dates and facts that may be the basis of a claim or defense, e.g., the date on which an event occurred for purposes of determining whether the statute of limitations has run. And they’re particularly useful in certain circumstances, such as:

• Getting information not obtainable from an individual deponent. When conducting discovery against corporations, e.g., in a products liability case, the plaintiff may need to discover information about every other person injured by the same product. Probably no individual employee of the corporation would know the answer, because it would require a search through records. An interrogatory would require the corporation to search its records and conduct a reasonable investigation to gather the information. It’s often useful to have a corporate deponent designate the person who’s most qualified to testify on specified matters.
• Following up after a deposition. Generally, each deponent may be deposed only once. (See Code Civ. Proc., § 2025.610.) Short of moving to redepose the individual, questions arising after the deposition should be addressed in interrogatories.
• Supplementing interrogatory responses. A party may propound a supplemental or “cleanup” interrogatory to require other parties to update their responses to all previous interrogatories with information acquired after those previous responses were made. (Code Civ. Proc., § 2030.070.) There’s no similar procedure for requiring a party to update answers to deposition questions.

For everything you need to know about using interrogatories and depositions, turn to CEB’s California Civil Discovery Practice, chapters 5-7.