Expert witness work can be a valuable asset in both criminal and civil court cases, providing unbiased and knowledgeable testimony that is often persuasive for a judge or jury.
However, presenting impartial opinions on complex or charged issues is no easy task, and your expert witness will not be helpful to you if they are not prepared. Before writing a report, or heading to a deposition or trial, your expert should be able to avoid the following seven pitfalls.
This is one of the easiest traps for an expert witness to fall into. They are experts, so their knowledge and understanding of the matter at hand are far more advanced than most people’s, including the attorney asking them questions.
However, preparation should never be taken lightly. The expert witness should not rest on their past experiences and education alone; there should always be effort put into preparing their opinions and testimony.
Consider this example of an overconfident expert witness: The plaintiff’s expert issued a report asserting that the device in question was defective and the design was unreasonably dangerous. However, upon questioning, he admitted that he never actually opened the device to examine the internal mechanisms and further admitted that he was not actually aware of how the device operated until he read the plaintiff’s expert’s report.
The testimony and opinions of an expert witness are only valid if they have specialized knowledge of the matters involved in the case. In fact, it is often necessary for a witness to qualify as an expert, which requires that they can offer some level of knowledge, skill, experience, training, or education. It is important to note that technical fields and industries often include nuanced specialties and categories. Ensure that the expert you choose is qualified to speak on the specific topic in question.
Engineering, for example, encompasses a broad range of careers and knowledge. A mechanical engineer with a background in HVAC was retained as an expert for a case involving a forklift accident.
The expert testified that a forklift was operated improperly because it was driven forward down a slope with a 1.27% grade despite the manual instructing loads to be driven down slopes with the load facing uphill (backwards). However, this expert lacked the specific experience to know that the forklift manufacturer considered a slope as a surface with more than 10% grade, thus the operation was in accordance with the manufacturers recommendations. This case settled shortly after a rebuttal report was issued pointing out this error (and some additional errors) in that expert’s report.
3) Unsupported Opinions
While expert witnesses are brought in for testimony or opinions because they are purported to be highly knowledgeable in their field, simply saying something is fact is not enough. There must be a basis for that opinion that proves the expert is providing accurate and reliable testimony.Rule 702 of the Federal Rules of Evidence lays out the requirements for this:
- The expert must base their testimony on facts or data;
- They must utilize reliable methods to reach their conclusion; and
- They must have applied reliable principles to the facts of the current case.
Daubert v. Merrell Dow Pharmaceuticals, Inc. was an important case for the issue of expert testimony and standards of scientific techniques. The decision in this case was that scientific techniques are inadmissible unless they are generally accepted by the scientific community. In this case, which has become a standard of sorts, the plaintiffs’ argument was not successful because their expert witness failed to support his opinion with accepted scientific methods.
In one case we have worked on, experts on the other side alleged a product defect where the descending panels of a rear loading garbage truck caused tree branches to jump out of the back of the truck, swing around the side and towards the front of the truck, striking the operator, who was standing at the controls, in the head.
The court concluded that “Ultimately, [plaintiff’s expert’s] report offers little insight into why he believes the [garbage truck] was defectively designed. While [plaintiff’s expert] criticizes Defendant’s engineers for failing to conduct an FMEA analysis that he argues would have highlighted the defective design, he admitted that any FMEA analysis that he conducted was “in my head” and never produced in writing.
Since no such test was produced in writing, the Court has no way of assessing its reliability… Additionally, [plaintiff’s expert] did not test or conduct research on the key questions bearing on whether a design defect existed. While Plaintiffs contend that the design of the [garbage truck] requires its operators to stand in a hazardous zone, [plaintiff’s expert] did not define the parameters of this zone or conduct any testing that could identify the conditions under which objects are expelled from the [garbage truck] and where they would typically land… Consequently… [plaintiff’s expert’s] opinions … are excluded.”
Bias is a natural and unavoidable part of the human condition. However, credibility is questioned and cases hang in the balance when intrinsic bias goes too far and clouds judgment. Your expert witness should be prepared to support their opinion through any cross-examination or questioning that may occur. Are there other possibilities aside from their conclusion? If so, why is their solution or opinion superior? An expert witness should be able to calmly address questions like these to prove they are unbiased.
There is no reason to include an expert witness in your legal strategy if they are not convincing. The added cost and effort that goes into obtaining an expert means that ensuring they are effective is crucial for your client. In addition, if the witness cannot form a solid opinion or conclusion about the matter, or cannot adequately express their opinions, they should not be asked to testify. An expert who is not convinced cannot convince a judge or jury.
6) Analytical Errors
Even experts are not infallible. Extra care needs to be taken to ensure your expert’s analysis is accurate. If the witness provides testimony based on faulty methods, incorrect data, or bad math, they could be excluded, and your case may fall apart.
In one case, involving a load that fell off the front of a forklift, the plaintiff’s expert provided calculations allegedly showing that with the load the forklift was carrying, it simply could not have tipped the forklift forward allowing the load to fall off of the front. However, the expert used an incorrect number in his calculations. The number was different from the measurements he took and documented. If the correct number had been used then it was clear that the forklift could indeed tip over. Accordingly, Plaintiff’s were unable to prove their case and were unsuccessful in court.
7) Lack of Credibility
Credibility is the most important asset of an expert witness. It is the basis of everything else the expert offers. Without credibility, none of the other factors in this list matter. How can you help your expert witness prove and maintain their credibility? Aside from ensuring that they offer relevant and extensive experience and knowledge, you can also work with them on how they present themselves. Their appearance and mannerisms affect their credibility, as do behavior and speech patterns. Expert witnesses should look and act the part. Help your witness speak without using filler words like “um,” “like,” and “you know.”
Dr. Mark Kroll’s testimony in the highly-publicized trial of Scotty Payne is an example of credible testimony. Dr. Kroll is a biomedical scientist with specific expertise in how electricity affects the body. He testified that none of the pulls on the Taser used by Payne were effective and that electricity does not linger inside the body. Payne was found not guilty of felony assault and use of a deadly weapon in the death of Zachary Bearheels.
Finding an expert witness that avoids these common mistakes and offers solid testimony can make a substantial impact and even be the difference between the success or failure of the case.
References For Additional Reading
Orti, Camila. KETV NewsWatch 7. Experts testify Scotty Payne’s Taser pulls were not effective on Zachary Bear Heels. https://www.ketv.com/article/experts-testify-scotty-paynes-taser-pulls-were-not-effective-on-zachary-bear-heels/25417356
Order in Case 2:19-cv-04724-PHX-GMS