Expert Witness

Expert witnesses play a vital role in personal injury cases by providing valuable insight and testimony on complex issues such as causation, product liability, and accident reconstruction. These experts can help to establish liability, prove damages, and clarify technical concepts for the jury. 

Below is an outline of the role of expert witnesses in personal injury cases and the importance of working with qualified experts to build a strong case.

Opinion vs. Fact

Ordinary witnesses must testify concerning the facts as they see them. Their job is to report what they personally experienced. They have very little latitude to report their opinions. The opposing party might even challenge a statement like “The defendant appeared to be intoxicated.”

By contrast, parties hire expert witnesses for the purpose of soliciting their opinions (typically through testimony). An expert may testify on almost any matter within their field of expertise as long as no rule of evidence forbids their testimony for independent reasons.


A party calling an expert witness to testify must qualify that witness to prove that they possess the expertise necessary to testify on the matters for which they are called. There is no uniform set of standards that apply to every expert witness. The applicable standards depend on the type of expertise for which the witness is called.

 Following are a few examples of relevant qualifications:

  • A license to practice medicine; 
  • A Ph.D. in a relevant field;
  • Publications in relevant academic journals;
  • Professional awards and recognition; and
  • A strong professional reputation.

A court will weigh these factors before it decides whether the witness is qualified. Whether an expert witness is qualified is essentially a subjective decision that can be appealed to a higher court.

The lawyer who calls the witness might seek expertise that would not interest the court, such as experience testifying in cross-examinations or a favorable reputation among the lay public. 

Consulting Witnesses vs. Testifying Witnesses

Lawyers frequently hire expert witnesses to offer testimony or private consultation with the lawyer. In some cases, expert witnesses provide both services.

Consulting Witnesses

Lawyers hire consulting witnesses to clarify aspects of a case with which they are unfamiliar. Suppose, for example, the opposing party’s case relies heavily on DNA evidence that supposedly identifies the lawyer’s client. 

The lawyer may seek a way to cast doubt upon the DNA evidence. If they lack the scientific background to do so, however, they can hire an expert witness to prepare an objective report on the feasibility of challenging this DNA evidence in court vs. settling the claim out of court.

  • If the report is unfavorable to the lawyer’s client, they will not ask the witness to testify, but they will better understand the strengths of the opposing party’s case. Additionally, conflict of interest concerns might prevent that witness from testifying for the opposing party.
  • If the report favors the lawyer’s client, the lawyer might ask the expert witness to testify in court. The witness may or may not agree to do so, since testifying might damage the witnesses’ standing within their professional community. 

The lawyer does not need to notify the opposing party of their retention or even the existence of a consulting witness who will not testify. 

Testifying Witnesses

As the name implies, a testifying witness researches a case, reaches a conclusion, and testifies in favor of the client whose lawyer hired them. Although the lawyer pays a testifying witness, the law expects the testifying witness to provide an honest opinion. Nevertheless, you can be sure the opposing party’s lawyer will notify the court of the fact that the witness is being paid.

The lawyer must inform the opposing party of the identity of any testifying witnesses. The opposing party can not only cross-examine them in court but can also cross-examine them at a deposition (out of court but under oath).

Examples of How Parties Use Expert Witnesses

Following are some examples of how parties use expert witnesses in court:

  • To prove medical causation–how the defendant’s actions caused the plaintiff’s injuries in a slip and fall accident, for example.
  • To show how a product defect caused the plaintiff’s injuries.
  • To reconstruct the sequence of an accident step by step.
  • To prove how much a long-term injury will diminish the plaintiff’s future earning capacity.
  • To quantify estimated future medical expenses.
  • To establish the extent of psychological harm, such as emotional distress or mental anguish.
  • To defend the conduct of a doctor who is being sued for medical malpractice.

Expert testimony can serve as powerful evidence in a personal injury case.

Contact a St. Petersburg Personal Injury Lawyer for Help

If you have been injured due to the negligence of another party, it is important to consider your legal options. A personal injury attorney can help you understand your rights and guide you through the process of filing a claim to ensure that you receive the compensation you deserve.

Contact Lopez Accident Injury Attorneys to schedule a free consultation to discuss your case at (727) 933-0015.