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A Step-by-Step Guide to Trials for Expert Witnesses

April 24, 2024
Gavel and law books

By Noah Bolmer

Trials do not usually unfold the way they are commonly depicted in popular media, and experts who haven’t been through the entire process may not know what to expect. While this overview will help demystify trials for expert witnesses, consider viewing recorded trials, or even attending one in person. 

A Glossary for Expert Witnesses

This list is by no means exhaustive, but cover both commonly used and commonly misunderstood terms which are relevant to expert witnesses: 

  1. Affidavit: A written statement made under oath by a person with knowledge of the facts of a case. 
  2. Bench trial: An action where the judge acts as factfinder in place of a jury.  
  3. Burden of proof: The responsibility of one party in a lawsuit to prove their claims by a certain standard. 
  4. Competency: Whether a witness has the capacity to understand the oath, perceive the facts they are testifying about, and accurately recall and communicate those facts. 
  5. Complaint: A formal document filed in court that outlines a plaintiff’s claims and the relief they seek. 
  6. Consulting expert witness: Advises the attorney and legal team on the case’s technical aspects, helps develop strategy, and may not even be known to the opposing party. Their work product is typically protected by attorney-client privilege. 
  7. Cross-examination: The questioning of a witness by the opposing party after the witness has been questioned by the party who called them. 
  8. Defendant: The party whom charges are brought against.  
  9. Daubert standard: A set of Federal guidelines used by judges to determine whether the testimony of an expert witness is based on reliable scientific principles and methods. 
  10. Deposition: A question-and-answer session under oath, outside of court, to gather evidence from an expert or witness. It is part of the discovery process. 
  11. Direct examination: The questioning of a witness by the party who called them to elicit their testimony. 
  12. Discovery: The pre-trial process by which both parties exchange information about the case, including witness lists, documents, and other evidence. 
  13. Exhibit: Any object, document, or piece of evidence presented in court. 
  14. Expert Witness: A person with specialized knowledge who explains complex issues to the court and helps them reach a decision. 
  15. Expert Witness Report: A written document outlining the expert’s qualifications, opinions on the case, and reasoning behind those opinions. 
  16. Expert Testimony: An opinion on a relevant topic, delivered in court by a qualified specialist under oath. 
  17. Finder of fact: The jury (in jury trials) or judge (in bench trials) who will deliver a verdict based on the testimony of both sides of a case.  
  18. Jury: A group of people who are sworn to hear the evidence in a case and reach a verdict based on the law and the evidence presented. 
  19. Matter: A situation, issue, or dispute, subject to laws and regulations within the relevant jurisdiction. 
  20. Motion: Requests made to the judge by an attorney to take a specific action. 
  21. Objection: A statement made by an attorney to the judge that a question or line of questioning is improper and should not be allowed. 
  22. Plaintiff: The party who files a lawsuit and brings a claim against another party. 
  23. Pleading: Formal written statements outlining claims and defenses.  
  24. Preponderance of the evidence: The standard of proof in most civil cases. It means that the evidence shows that something is more likely true than not true. 
  25. Rebuttal report: An expert witness report that specifically responds to and aims to weaken the opinions presented by the opposing expert’s report. 
  26. Rebuttal witness: A witness called by a party after the other party has rested their case to respond to new evidence or arguments presented by the other party. 
  27. Redirect: The attorney who calls a witness asks a series of clarifying questions after cross-examination.   
  28. Response: A legal document filed by the opposition in response to a complaint, pleading, or motion.  
  29. Settlement: An agreement resolving a dispute outside of court. 
  30. Testifying expert witness: Appears in court, delivers their opinion on relevant matters, and undergoes questioning by both sides. Their reports and work are subject to discovery by the opposing party. 
  31. Trial Team: lawyers and support staff working together to present a case in court. This may include paralegals, assistants, experts and consultants.  
  32. Voir dire: The questioning of potential jurors by the attorneys and the judge to determine whether they are qualified to serve on the jury. 

A Trial Overview 

A jury trial is broadly divided into three phases: The pre-trial, trial, and post-trial. Expert witnesses are used by both plaintiff and defendant and are typically brought on during the pre-trial period, but this is not always the case. Your engagement may start during the trial phase, or even in the post-trial period under limited circumstances.  


Once a complaint has been filed, legal proceedings commence, and the pre-trial phase begins. During pre-trial, both sides’ attorneys may make motions, request hearings, engage consultants, and seek out expert witnesses. Expert engagements are made directly, or through an expert witness firm like Round Table Group 


Once you secure an engagement, you will meet with the trial team to discuss the case, prepare, and define your role. Depending on the case, you may receive an extensive load of background materials including the complaint, answer, pleadings and motions. Additional discovery documents may be provided if they are relevant to your role during the case. Expert witnesses should familiarize themselves will all materials provided, as attorneys will typically provide experts only with documentation that is relevant to the engagement. Sometimes, attorneys will provide additional research documents that will bolster their client’s case. Additionally, a jury consultant might be brought in, especially for high-stakes cases.  

Expert Witness Depositions

Expert witnesses are part of the discovery process, and this may include a deposition. A deposition is an out-of-court question and answer session under oath, where attorneys will gather information about an expert’s qualifications, strengths, and weaknesses prior to trial. A deposition follows a similar format to a trial, where there is a direct examination by your attorney, cross-examination by the opponent attorney, and possible redirects. Deposition transcripts and recordings are part of the record, and any answers given may be used to impeach the witness during the trial.  

Daubert Hearings 

In Daubert v. Merrell Dow Pharmaceuticals, Inc., the Supreme Court made trial judges arbiters of whether an expert witness’s testimony is admissible.  The specifics depend on the field of the expert, but the opposing side can raise a “Daubert challenge” which triggers a hearing. In a Daubert hearing, the burden of proof is on the party who wishes the expert to testify, which is why attorneys carefully vet expert witnesses prior to engagement. During the hearing, the judge will consider whether the expert is credible, qualified, has a reliable basis upon which to base an expert opinion, and whether the testimony is relevant to the case. While the Daubert standard applies in Federal jurisdictions and most states, some states use a modified version, or a different standard. It is important to verify with the engaging attorney which standard applies to prepare for any potential challenges. 

The Trial 

Trials take place before a judge (in bench trials) or a judge and jury (in jury trials). The specifics vary across venues, but the overall cadence is fairly regular for most US courts. There is no set amount of time; with trials lasting from seven minutes to nearly seven years in one case 

Opening Statements 

Once the trial begins, the attorneys for both sides give opening statements where they lay out their case and go through any evidence they will present. Expert witnesses are not involved in this phase and are typically absent. Once opening statements are given, each side presents evidence through witness testimony, including expert witnesses. 


During direct examination, the attorney will call witnesses, ask them questions, and refer to any exhibits that have been prepared. Through careful pre-trial preparation, experts will already know what questions will be asked, and any likely objections that might be brought. Experts may refer to their reports (which both sides will have through discovery) during any testimony in most jurisdictions. This highlights the importance of having a well-organized report, especially for complex cases. Expert witnesses, having specialized knowledge in their field, state their opinions for the record, which the fact-finder will take into account when determining a verdict.   

The opposing side will have the opportunity to raise objections during direct examination, and then conduct a round of questioning during cross-examination. Preparation for cross-examination is one of the fundamental tasks during pre-trial, and expert witnesses should feel well-prepared for this phase prior to entering the courtroom. After cross, your attorney may have the opportunity to redirect, where they may ask a series of questions to address points raised during cross.  

Sometimes, witnesses are called (or re-called) specifically as rebuttal witnesses. The sequence is identical, but the questioning will be geared toward dismantling the opponent witness’s earlier arguments, and any new points raised during trial. Even when another witness is called, experts will typically pay attention to rebuttals, as any new points brought up may color their testimony. 

Closing Arguments 

After all testimony concludes, each side delivers a closing statement summarizing their case. While closing statements often mirror opening statements, they will focus on the strength of their witness’s (including expert) testimony, diminish the opponent’s testimony, and try to convince the jury that a friendly verdict must be entered. Because all testimony has concluded, expert witnesses do not play a role in this part of the trial and are usually not present.  


A trial concludes when a verdict is reached, or the sides agree on a settlement. Settlements are very common and may occur before or during the trial. While settlements may cut short the engagement, they do have some effects on expert witnesses. Often, settlements include a confidentiality arrangement which binds experts. Also, payment terms may be affected by settlement, and it is important to address this through the engagement contract  

While verdicts and settlements mark the end of the case, the matter may continue to move through the court system through the appeals process. While experts are not typically involved in appellate actions, there are exceptions when a new legal issue emerges on appeal or there is a highly technical issue which requires an expert.   

Some attorneys will follow up with expert witnesses to address the outcome and performance. While not every attorney will do this automatically, many experts find a debrief invaluable to future performance. Additionally, staying in touch with the engaging attorney will strengthen that relationship, and help secure future engagements.   

Through experience, experts will become more comfortable with the flow of trials. It is important to keep an open line of communication with your attorney for the specifics, especially for newer experts, and when working in an unfamiliar venue. Careful preparation will help you to feel comfortable, confident, and ready for each phase of the trial and every new engagement.   

Consider signing up with Round Table Group for expert witness opportunities. For nearly 30 years, we have helped litigators locate, evaluate, and employ the best and most qualified expert witnesses. Contact us at 202-908-4500 for more information or sign up now! 

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