The use of expert witnesses has become commonplace across the American legal landscape, and attorneys must develop the ability to challenge opposing experts during the course of the trial process. In an effort to keep experts away from juries, most attorneys will attempt to preclude opposing expert witnesses from providing testimony by either challenging the expert’s credentials or calling into question the methods the expert used to develop his or her testimony. In the New York lawsuit, Valente v. Textron, a defendant in a personal injury case successfully used both tactics to prevent two plaintiff expert witnesses from testifying.

Qualifying an Expert Witness for Trial

When questioning the qualifications of an expert or the soundness of his conclusions, courts will rely on the Daubert standard. Under Daubert, an expert may only testify if he satisfies the requirements under Federal Rule 702, and if his testimony is both relevant to the issue at trial and based on reliable scientific evidence and knowledge.

Central to a judge’s decision is whether or not the testimony is derived from a scientific methodology – a determination that can be made based on a variety of factors, including:

1. Whether the theory has undergone empirical testing
2. Whether the theory has been subjected to peer review and publication
3. The existence of professional standards in the industry
4. The degree to which the theory is generally accepted by the scientific community

In addition to the scientific knowledge requirement, an expert must be qualified to reliably apply the principles and methods to her analysis of the case. In Valente, the plaintiff was unable to provide experts who were able to both demonstrate their qualifications and prove that their testimony was based on scientifically reliable methodology.

Challenging Expert Witness Credentials

The Valente plaintiff, 18-year old Matthew Valente, suffered a devastating and permanent injury after he lost control of the E-Z golf cart he was driving. Valente sued the manufacturers of the golf cart, E-Z Go company, alleging that the break system was faulty and the vehicle lacked appropriate safety equipment or adequate warning about improper use. Plaintiff expert witness Bruce Gorsak, who has a bachelor’s degree in mechanical engineering and used to work for manufacturer E-Z Go, intended to testify that the E-Z golf cart was unsafe because it had a 2-wheel break system and lacked a safety belt. However, the defendant argued he was unqualified as an expert witness.

In challenging Mr. Gorsak’s ability to testify in the case, E-Z Go pointed out that none of his analysis nor understanding of the cart’s safety features were based on peer reviewed scientific studies, and his claims that the safety warning was inadequate were made without actually knowing what the golf cart’s warning said. By proving that Gorsak was unable to support his testimony with the factors articulated in Daubert, E-Z Go’s defense team was able to convince the judge that he would not present reliable testimony and was therefore unqualified as an expert witness.

Challenging Expert Witness Testimony

Typically more effective is to challenge the methodology used by the expert to generate his opinions, and the E-Z Go defense was able to disqualify forensic engineer Kristopher Seluga in this manner. After stipulating to Seluga’s qualifications as an engineering expert familiar with rear-wheel braking systems, the E-Z Go attorneys turned their focus to the method Seluga used to evaluate the accident scene and arrive at his conclusions about the case.

Mr. Seluga inspected the accident scene, took various measurements of acceleration, and used a computer simulation program to determine that the golf cart’s brake system caused it to enter a dangerous spin and tip, causing Mr. Valente’s injuries. Upon analyzing Mr. Seluga’s computer simulation, the court found that he had written the code himself and did not have the process reviewed by other experts in his field. Further, Seluga’s model was designed for vehicles larger than golf carts, and was not commercially available for use and critique by others.

Under the Daubert standard, the court determined that Mr. Seluga’s simulation model was not validated by proper scientific method and therefore was “wholly inadmissible.” Without a proper scientific basis for his methodology, Seluga’s testimony was disallowed as being unreliable. The Valente case provides a demonstration of two effective means of challenging and disallowing opposing expert witnesses, both relying on the Daubert standard of qualifying experts for trial.