Is It Expert Testimony Or "Junk Science" Coming From The Witness Stand?

26 Jul 2007

Technical matters in the fields of forensic science and engineering are often the subject of expert testimony in civil trials, including those seeking damages for an injury or death. Accident reconstruction, failure analysis and engineering analysis, among other technical areas of expertise, often contribute to the development of evidence that significantly affects the course of a trial.

Technical experts are permitted to express opinions on scientific information that is above the knowledge level of the typical juror. The intent of the court is to use the scientific expert testimony to help the "trier of fact" understand and rule reasonably on complex technical cases. Expert witnesses now offer opinions on virtually any subject.

It is not unusual for comparable experts to be presented by each side with opinions that directly contradict each other. It is left to the jury to decide which expert is the more "scientific" or correct in his or her opinions.

In his 1991 book, "Galileo's Revenge: Junk Science in the Courtroom," Peter Huber implies that some expert testimony has little basis in scientific fact and is plain junk, hence the birth of the popular term, "junk science." A recent television documentary by ABC focused on idiotic "scientific" testimony, an uncomplimentary exposé of obviously flawed science and the legal profession. The courts, appearing to be fed up with junk science, attempted to correct the condition of unscientific scientific testimony through a U.S. Supreme Court decision in the 1993 Daubert v. Merrill Dow Pharmaceuticals (509 U.S. 579, 1993) court action.

The Daubert Decision

In Daubert v. Merrill Dow Pharmaceuticals, the high court concluded that trial judges should act as "gatekeepers" and not let in testimony based on junk science. When admitting expert testimony under the Federal Rules of Evidence, the U.S. Supreme Court identified the following four standards for the admissibility of scientific evidence:

• Has the scientific theory or evidence been tested?
• Has the scientific theory or evidence been published or subjected to peer review?
• What is the error rate of the theory or technique and are there controlling standards?
• Has the scientific community generally accepted the theory or technique?

The Supreme Court stressed that these four standards should be applied in a flexible manner and are non-exclusive. What has resulted from this ruling is a legal phenomenon known as a "Daubert hearing," in which one side tries to knock out the expert testimony of the other side by applying one or more of the four gatekeeper guidelines. It has been argued that under Daubert, technical testimony based on deductive reasoning such as that used by fire investigators and accident reconstructionists was nonscientific and excluded under Daubert. Arguments have ensued over whether technical knowledge is scientific or whether fields such as fire investigation are scientific.

Where Do We Stand?

The full meaning of the Daubert decision is not entirely clear to judges and attorneys who are involved in technically related litigation. On a case-by-case basis the future is being charted.

In a very real sense, the Daubert decision makes non-scientists scientific gatekeepers. This may result in "good science" being excluded from the courtroom. A prime example is the understanding of the scientific field of biomechanics (see Insurance Adjuster, April 1985). Biomechanics is the study of the effects of forces and motion on the human body. Engineers perform biomechanical analyses to design automobile air bags, ski bindings, aircraft ejection seats and many other products. Many judges do not understand the difference between biomechanics and the field of medicine. They often mistakenly consider biomechanical analyses to be medical testimony and are known to bar such testimony when provided by engineers or other non-physicians who are skilled in that field.

Likewise, an electrical engineer may be barred from expressing opinions on a mechanical device even though mechanical and electrical engineers have virtually identical course work in the first two years of engineering school. There are many mechanical engineers who are skilled in failure analysis yet their testimony on failure modes analysis may be barred because they do not have a degree in metallurgy, even though courses on metallurgy are an integral part of mechanical engineering curricula.

Science and technology are constantly evolving and developing new knowledge, procedures, techniques, and disciplines. It is important that in the search for truth our courts do not become merely the guardians of the "old truth" or the old way of looking at things.

Some courts have resorted to hiring "independent" experts to evaluate the scientific testimony from each side. Their reports may act as a basis for a decision in a particular action. While this can arguably be said to advance the cause of finding the truth it will most certainly create delays and additional expense in litigation. And, there is no guarantee that the expert selected by the court will be any better qualified than the ones selected by the parties.

In the future, defense attorneys will most likely be helped by the broadened Daubert decision, in that there is a better opportunity to exclude testimony. It is possible that fewer cases will make it to a jury after surviving a Daubert challenge. More intense pre-trial Daubert-related court battles are expected, driving more claimants to more economical and less time-consuming methods of alternative dispute resolution.

It will be more important than ever to select experts familiar with the rigorous challenges to their testimony that can be expected. And, more important than ever to be represented by a competent attorney prepared to overcome these challenges.