21 Jan 24

Federal Subpoenas for Expert Witness Testimony: A Litigation Guide

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Last Updated on: 21st January 2024, 10:46 pm

Federal Subpoenas for Expert Witness Testimony: A Litigation Guide

Expert witnesses can play a crucial role in federal civil and criminal litigation. However, securing expert testimony often involves navigating complex rules around subpoenas. This guide provides an overview of using federal subpoenas to obtain expert witness testimony.

Overview of Federal Subpoenas

A subpoena is a writ ordering a person to appear at a proceeding or trial. It can also order the production of documents or other evidence. In federal court, subpoenas are governed by Rule 45 of the Federal Rules of Civil Procedure.There are two main types of federal subpoenas:

  • Trial subpoenas – Require a witness to appear and testify at a trial, hearing or deposition.
  • Document subpoenas – Require a person or entity to produce documents, electronically stored information, or other tangible evidence.

Federal subpoenas have force nationwide. So a subpoena issued from a court in one district is valid throughout the United States. Failure to comply can result in civil or criminal contempt sanctions.

Using Subpoenas for Expert Witnesses

Litigants in federal cases often use subpoenas to obtain two main forms of expert witness discovery:1. Deposition TestimonyA common approach is to subpoena an expert witness and take their deposition. This allows the attorneys to probe the expert’s credentials, opinions and the bases for them. It also locks the expert into a specific position.2. Production of DocumentsAnother approach is to subpoena an expert’s documents, including draft reports, notes, communications and other materials. This provides insight into the expert’s views and how they evolved over time.In some cases, a subpoena will seek both an expert’s deposition testimony and documents. Attorneys use the testimony to clarify and expand on the expert’s written materials.

Rules and Limits

There are several important rules around subpoenaing expert witnesses in federal court:

  • Fees for time and travel must be tendered – This includes a reasonable fee for time preparing for and giving testimony.
  • Scope is limited by relevance and proportionality – Subpoenas must not impose an undue burden or seek privileged/protected information.
  • Sensitive patient information may require court order – Extra protections apply when subpoenaing medical experts.
  • Subpoenas usually can’t force experts to generate new analyses or opinions – Courts typically prohibit such involuntary draft reports.

Experts also can file motions to quash or modify subpoenas that are overbroad or impose hardship. Courts will weigh factors like relevance, need, breadth and burden.

Key Strategic Considerations

Subpoenaing opposing experts requires strategic planning. Counsel should consider:

  • Locking the expert into a position early – This can limit later changes to theories or methodologies.
  • Probing credentials and qualifications – Attacking these areas can undermine expert opinions.
  • Obtaining a roadmap for cross-examination – Depositions allow broad exploration of vulnerabilities.
  • Assessing if the expert has been improperly influenced – Materials may reveal subtle impacts on objectivity.
  • Preserving testimony for use at trial – Depositions can be used for impeachment if experts change positions.


Federal subpoenas are important tools for obtaining discovery from expert witnesses. But subpoenaing experts also raises complex issues on topics like fees, confidentiality, scope, and privilege. Counsel should craft an approach tailored to case needs while avoiding pitfalls that may undermine expert testimony. With careful strategy, subpoenas can yield critical evidence and also set the stage for effective cross-examination.


Overview of Federal Subpoenas – AvvoUsing Subpoenas for Expert Witness Discovery – FindLawExpert Witness Fees and Compensation – LawInfoChallenging Overly Burdensome Subpoenas – NoloRules for Subpoenaing Medical Experts – HG Legal ResourcesCourt Limitations on Expert Fishing Expeditions – Rutter Group Practice GuideFiling Motions to Quash or Modify Subpoenas – Justia