THE MONTHLY ADJUSTMENT

INTRODUCTION

Many people have commented that we in the United States today are the most litigious society in the history of the world.  Many people in this country feel that pursuing legal remedies for injuries they believe they have suffered should be a first, rather than a last, resort.  In most cases, the Plaintiffs truly believe they have suffered injuries or wrongs because of the actions or inactions of the Defendants.  In a minority of other cases, individuals have been known to give false information in an attempt to be awarded large sums of money (millions to hundreds of millions of dollars). 

It is the task of the expert witness to seek out the truth of the claims and counterclaims that are typically made in these cases.  Obviously, the Plaintiffs and the Defendants will have their quite divergent positions about injury and fault.  It is the job of the attorneys hired by each party to act as an advocate for that party.  The expert witness, however, must not act as an advocate.  The expert has to be impartial and independent.  The task of the expert is only to determine if there is any scientific evidence that the injuries the Plaintiff claims were actually caused by something the Defendants did or failed to prevent.

I am a toxicologist.  The kinds of legal matters in which I get involved are usually those known as toxic tort cases.  In a toxic tort case, a person or persons (the Plaintiffs) allege that they have been injured because of their exposure to potentially toxic chemicals that have been released into the occupational or community environment by someone else (the Defendants).

In toxic tort cases, the main issue to be addressed by the expert witness toxicologist is one of "causation".  In legal terms, there are two types of causation, general and specific.  General causation is addressed by answering the question "can the exposure to Chemical A cause Medical Condition X?"  Specific causation addresses "was the actual exposure that the Plaintiff had of sufficient magnitude, frequency, and duration to have caused the medical condition?"  The expert must show that the probability that exposure to A caused Plaintiff's X must be greater than 50 percent (that is, “more likely than not”).  It is also part of the expert’s job to consider other possible causes of the Plaintiff’s injuries. 

All expert witness testimony must conform to certain legal rules.  In this article I will give an overview of the development of and the current state of such rules.

LEGAL BACKGROUND CONCERNING EXPERT WITNESS EVIDENCE

Early Developments Concerning Admissibility of Evidence

Judicial rules and guidelines for expert testimony have evolved over the years.  The first major ruling concerning admissibility of expert testimony came in 1923 in the Frye v. United States case.  In this matter, the court held that deductions made in testimony must follow from scientific principles that are "...sufficiently established to have gained general acceptance in the particular field in which it belongs."   In other words, an expert must base his or her testimony on generally accepted principles in the field of science in which he or she is an expert. 

Federal Rules of Evidence

The next major developments in this area of the law are codified in the Federal Rules of Evidence first published in 1975.  While Rules 701 through 706 pertain to expert witnesses and their testimony, Rules 702 and 703 are the most important guidelines as to the admissibility of expert testimony.  The original Rule 702 spoke to the issue of qualifications of the witness:

"If scientific, technical, or other specialized knowledge will assist the trier of fact to understand the evidence or to determine a fact in issue, a witness qualified as an expert by knowledge, skill, experience, training, or education, may testify thereto in the form of an opinion or otherwise."

The original Rule 703 addressed the basis for expert opinions.  It states as follows:

"The facts or data in the particular case upon which an expert bases an opinion or inference may be those perceived by or reviewed by the expert at or before the hearing.  If of a type reasonably relied upon by experts in the particular field in forming opinions or inferences upon the subject, the facts or data need not be admissible in evidence."

Recent Developments Concerning Admissibility of Evidence

There have been two major Supreme Court rulings within the last 12 years that have had a great impact on the field of expert witness testimony.  These were in the Daubert v. Merrell Dow Pharmaceuticals and Kuhmo Tire Co., Ltd. et al. v. Carmichael cases.  Based on these rulings, there have been amendments to the Federal Rules of Evidence concerning expert testimony.  The courts now more strongly emphasize that expert testimony be based on well-established and generally accepted scientific theories. "Novel" theories or approaches will usually be rejected as inadmissible under these new guidelines. 

Daubert v. Merrell Dow Pharmaceuticals

The ruling in this case, made in 1993, is often cited when attorneys talk about expert witnesses and their testimony.  One outcome of this ruling was the finding that the trial judge should function as a "gate keeper" who must rule as to the admissibility of particular scientific testimony from experts.  The judges are to use two main criteria in performing their gate keeping function.  These are 1) whether the testimony is truly based on scientific knowledge and 2) whether the testimony is "helpful" to the trier of fact.  These issues are sometimes referred to as "reliability" and "relevance" respectively.

Kuhmo Tire Co., Ltd. et al. v. Carmichael

The Kuhmo Tire case, decided in 1999, expands the concepts of Daubert to apply to all experts, including those with nonscientific, technical, or other specialized knowledge.  Thus, the fact that an expert does not give strictly "scientific" testimony does not exclude him or her from the Daubert guidelines.  The Supreme Court ruled that the Daubert principles should apply to this type of testimony as well.

Amendments to Federal Rules of Evidence

Rules 702 and 703 of the Federal Rules of Evidence were amended based on the rulings in the Daubert and Kuhmo Tire cases.  These changes took effect on December 1, 2000.  Additional language (italicized below) was added to each of these rules to further clarify the issues addressed in these rules.  The new Rule 702 reads as follows:

“If scientific, technical, or other specialized knowledge will assist the trier of fact to understand the evidence or to determine a fact in issue, a witness qualified as an expert by knowledge, skill, expe­rience, training, or education, may testify thereto in the form of an opinion or otherwise, if (1) the testimony is based upon suffi­cient facts or data, (2) the testimony is the product of reliable principles and methods, and (3) the witness has applied the prin­ciples and methods reliably to the facts of the case.”

The new Rule 703 now reads:

“ The facts or data in the particular case upon which an expert bases an opinion or inference may be those perceived by or made known to the expert at or before the hearing. If of a type reason­ably relied upon by experts in the particular field in forming opin­ions or inferences upon the subject, the facts or data need not be admissible in evidence in order for the opinion or inference to be admitted. Facts or data that are otherwise inadmissible shall not be disclosed to the jury by the proponent of the opinion or infer­ence unless the court determines that their probative value in as­sisting the jury to evaluate the expert’s opinion substantially out­weighs their prejudicial effect.”

Summary of Legal Guidelines for Giving Expert Testimony

There are four central questions concerning the admissibility of expert testimony.   These are as follows:

C                   Is the expert qualified to give the opinion?

C                   Is the expert's opinion based on appropriate scientific reasoning and methodology?

C                   Is the expert's opinion based on reliable data?

C                   Is the expert's opinion relevant to the trier of fact in the case?

To be successful, the expert witness must be aware of these hurdles and must be able to clear them so that he or she can be successful in providing accurate, useful information for the judge and jury. 

CONCLUSION

Providing litigation support services as an expert witness is a professionally challenging and rewarding undertaking.  In many ways, giving expert testimony is no different from other tasks that are more commonly performed by scientists and engineers.  Whether or not a person is involved as an expert in a legal case, scientific work should be done based on methods that are recognized and accepted by the scientific community.  As long as the expert witness follows these guidelines, they will be able to function in the legal arena as well as in the laboratory.