Interrogatory vs. Deposition: Discovery Comparison

Deposition conference room

The discovery phase is often the most critical component of legal work, leading 95% of civil cases to a settlement negotiation instead of a courtroom trial.1 Given this, how information is collected from potential witnesses is a critical decision, particularly if witness reliability is in question. 

Below, we’ll walk you through two types of witness discovery, comparing and contrasting interrogatory vs. deposition options to help you decide when to use each in building your case. Once you discern the differences in these testimony types, understanding other nuances—like a deposition vs. testimony—becomes a bit simpler. 

Exploring Interrogatories and Depositions

Interrogatories and depositions allow attorneys to gather information and question potential witnesses. They both result in documents that can be introduced as evidence and to impeach witnesses during trial. 

Legal teams can use both types of questioning in a case, selecting the method most useful for each witness based on a number of factors, such as: 

  • How critical their testimony is to a case
  • Whether their testimony is unbiased or they have a vested interest in the outcome
  • If the witness is believed to be unreliable or likely to prevaricate
  • Distance and availability

Both types of questioning are governed at state and specific court levels, so while the Federal Rules of Civil Procedure are a good starting point, guidelines may differ depending on your case’s jurisdiction.


An interrogatory is a method of questioning a witness in writing. The attorney presents a list of written questions to a witness, and the witness provides written responses. 


  • Are answered under oath by signing a verification of truthfulness form with a notary
  • Are under penalty of perjury for false or incomplete statements 
  • Can be responded to with objection plus a limited response per jurisdictional guidelines
  • Should be mailed back to their source, not submitted to the court

The process is fairly straightforward, but framed by limits on timing and number of interrogatory responses. Under the Federal Rules of Civil Procedure, limits (unless otherwise ordered by the court) include2

  • 25 written discovery interrogatories [questions], including all discrete subparts
  • 30 days for respondents to prepare and provide answers and/or objections


Depositions are much more complex in scope and in terms of requirements than interrogatories. Deposing attorneys can choose from multiple formats: 

  • Oral deposition, either in person, remote, or hybrid (with optional audio and video recording)
  • Telephonic
  • Written 

Unlike an interrogatory, a written deposition is still “live” for the witness. The court reporter is present to swear in the witness and create a verbatim transcript of what transpired. The attorney then questions the witness directly. 

Regardless of format, a deposition is a formal legal proceeding recorded by verbatim transcription that includes these steps3

  1. Official opening by a court reporter or court official
  2. Swearing in of witnesses under oath by a court reporter or sanctioned individual
  3. Direct examination (and re-direct) by the deposing attorney
  4. Cross-examination (and re-cross) by opposing counsel
  5. Official closing by the court reporter or court official
Trail consulting to help make strategic decisions. Request a Consulatation!

How to Prepare Witnesses for an Interrogatory vs. Deposition

Regardless of the format, you’ll want your witnesses to know what to expect and how you can support them from objectionable questioning. Because of the time required for this step, utilizing technical tools like AI for legal discovery can help you maximize the time you have to prepare your witnesses.


If your witnesses are served interrogatories, the responses must be their sworn testimony—but that doesn’t mean answering in the dark. Respondents can consult the attorney representing a case they’re witnessing in favor of, and potentially their own attorneys, to: 

  • Identify objectionable questions and craft appropriate objections
  • Answer objectionable questions within the bounds of their objections
  • Review witness responses to ensure they remain concise and limited to the question
  • Share information

Request that your witnesses share any incoming interrogatories along with other discovery requests as soon as they are presented. This helps to avoid being hit with a last-minute request to consult on answers before they’re due back. 


Preparing a witness for a deposition is a much more in-depth situation. It may involve: 

  • Preparation for questioning – Depending on the complexity, emotional aspects, and critical nature of testimony, witness preparation can include anything from a short call noting what type of deposition questions to expect, to running through mock questioning with various scenarios.
  • Looking the part – Provide tips on self-presentation, including appropriate clothing and accessories for the proceeding and their own comfort during a lengthy deposition. 
  • Technology tips – Ensure they understand and potentially test technology, particularly for remote depositions, and put it to best use (i.e., sound, lighting, and camera placement). 

Strategic Use in Litigation

It’s not an either/or end game for case discovery—you can use a combination of depositions and interrogatories both across witnesses and even with the same witness. Consider:

Benefits of Interrogatories

A simple solution to a simple situation. The limited, written questioning of interrogatories means: 

  • Less time – Coordinating a time, date, and location amenable to all parties and then conducting a deposition that can take hours is time-consuming. The elements of an interrogatory—composing, presenting, responding, and reviewing—can be broken down at the convenience of each party. 
  • Lower cost – An interrogatory doesn’t require the cost for a court reporter or videographer to be in attendance, nor travel or remote facilities or technology to be arranged. 
  • Better information governance – While the extent of questioning is much higher in depositions, so is the document page count to study and manage. The efficiency of interrogatories isn’t just about less initial time and money invested, but about streamlining case files and arguments to useful information without unnecessary bloat. 

Benefits of Depositions

If you’re hoping to “float like a butterfly, sting like a bee,” then you’ll opt for a face-to-face deposition. Depositions allow for: 

  • More questioning – While depositions do have time limits, they can last for hours or multiple days in some jurisdictions, which can permit hundreds of questions. Interrogatories, on the other hand, are limited to a maximum number of questions. While some states and courts allow more than the Federal Rules of Civil Procedure, Federal Rule 33 restricts the number of questions to 25 when presenting interrogatories. 
  • Responsive question design – What if the answer to question A impacts how you craft question B? While interrogatories allow for a prepared set of questions that have zero interaction with the respondent’s answers, a deposition allows you to adjust the tone, language, or direction of questions in response to what you hear and observe from the witness in real time. 
  • Emotional impact – A live or video-recorded deposition can capture emotion and nuances through facial expression and body language that you cannot achieve in a written interrogatory. Whether emotion is needed to underline the seriousness of a transgression, or a witness’s truthfulness is in question, depositions simply offer more complete data than written responses.
  • Testimony replacement – An official deposition can take the place of a live witness during a trial, allowing the judge and jury to view a video that’s more compelling than reading written answers into evidence. 
  • Aggressive questioning – If a witness is understood to be reluctant, hostile, or prone to lying, a deposition will allow you to ramp up questioning and stand firm in demanding a response. Interrogatories are passive vehicles that allow respondents to take their time and more easily deflect questions they don’t wish to answer. 
  • Factually complex – Expert witnesses may bring an “Aha!” moment to a case, but only if their testimony remains clear and believable after cross. If you’re facing a scientific or technical expert, you may need to measure and test their ability to prove their expertise or the theories presented to discover how they’ll hold up within a trial context. 

Support for All of Your Litigation Support Service Needs

Since 1996, U.S. Legal Support has provided exceptional litigation support services to lawyers, law firms, and other organizations. We connect our clients with a network of more than 5,000 skilled, certified court reporters and transcriptionists across the United States. 

At U.S. Legal Support, we pride ourselves on a high standard of work so that you and your firm can receive the support you need. Beyond that, we have a robust understanding of the modern legal industry, including the difficulties surrounding eDiscovery challenges, AI tools, and more. 

We can facilitate your remote and hybrid legal proceedings, provide complete transcription and translation services, and perform nationwide remote depositions, records retrieval, analysis, and organization — all managed via a Client Portal with cybersecurity and data privacy governance in place. 

Contact us today by phone, email, or website request form to discuss how we can help with your litigation planning and upcoming discovery proceedings.


  1. The Law Dictionary. What Percentage of Lawsuits Settle Before Trial? What Are Some Statistics on Personal Injury Settlements?
  2. Cornell Law School. Rule 33. Interrogatories to Parties.
  3. Cornell Law School. Rule 30. Depositions by Oral Examination.
Julie Feller
Julie Feller
Julie Feller is the Head of Marketing at U.S. Legal Support. Prior to U.S. Legal Support, Julie worked at Abacus Data Systems (now Caret Legal) providing legal technology platforms and services to legal professionals across the country.

Editoral Policy

Content published on the U.S. Legal Support blog is reviewed by professionals in the legal and litigation support services field to help ensure accurate information.