8.4 The Scientific Witness

• 8.4.1  Witness: Fact vs. Expert
• 8.4.2  Scientific Defense 

An FDA analyst's role in the courtroom is to serve as a scientific witness.  The analyst needs to attest to what took place while examining a product in the laboratory.  He or she provides an explanation of the underlining science and scientific testing procedures used to test the product.  Most analysts serves as witnesses of fact.

8.4.1  Witness: Fact vs. Expert

Witnesses presenting scientific testimony fall into two categories: witnesses of fact and expert witnesses. Fact witnesses, even those who have scientific training, can testify only to matters of fact that they have witnessed. They cannot give opinions. The expert witness is one who, by special study, practice, and experience, has acquired special skill and knowledge in relation to some particular science, art, or trade. Obviously, therefore, a fact witness does only what his or her oath charges, namely, to tell the truth, the whole truth, and nothing but the truth. 

Qualifying as an expert involves an examination of the individual's academic credentials and the duties connected with his or her career, past and present, such as various professional achievements and the publication of original scientific papers. The possession of a bone fide degree from a State university or employment of some duration by a State or Federal agency in the scientific field covered by the testimony practically ensures that the judge will admit a person as an expert. If a person is trained in a State's educational system and presented with a diploma, the State's judicial institutions cannot deny these credentials without good cause. Previous expert testimony also helps to qualify a person as an expert witness.

The main reason for expert testimony is to interpret difficult-to-comprehend facts to the jury. The judge usually explains to the jury that the court will permit the expert to evaluate the evidence and explain its significance to the case being examined. Even though an expert witness is entitled to give opinions, usually more than a mere statement of opinion is usually needed for maximum impact. The expert witness should know or conclude that certain conditions or findings prove the statements he or she makes.

8.4.2  Scientific Defense 

One of the burdens of proof in a case involving scientific testimony is that the science is sound and accurate. For example, in a case involving misbranding or adulteration, the prosecution demonstrates, beyond a reasonable doubt, that the product is actually misbranded. If the charge is subpotency of a drug, the science first shows that the drug in question is actually subpotent, if this is the basis of the allegation. This type of proof usually is provided by the analyst who analyzed the sample in question. The proof may be provided in the form of written results on the worksheet or verbal testimony of the analyst. In many cases the defense may stipulate to the report of the analyst. In other words the defense is saying that they do not contest the report, nor do they question the integrity of the analysis performed. In such cases, the analyst may not be asked to testify.

In other instances the entire basis of the defense may be that the results found are totally inaccurate. For example, the insect fragment in the soup was not actually an insect but an exotic vegetable; the drug analyzed was not subpotent because the chemist did not know what he or she was doing; the Salmonella found in the cheese was actually a result of cross contamination in the laboratory caused by a technique error made by the microbiologist. In these situations the analyst may be asked to testify.

The basis of a scientific defense is to cast doubt on the conclusions drawn from the analysis. This type of defense can be difficult to perform because the defense attorneys may not know enough about the subject to ask the right questions. Even if they learn enough to ask the right questions or are knowledgeable about the science, the jury may not understand what is being said. In cases where the defense brings in expert scientific witnesses to contradict the testimony and the conclusions of the prosecution's scientific witness, there is always the problem of whom the jury will believe.

Scientific defenses are generally a last resort when no other defense is feasible, or when the science is poor enough to warrant a court challenge. Nonetheless, an attorney who decides to use this defense will do his or her homework and at least gain an understanding of the principles behind the primary tests performed by the analyst. Without this knowledge the defense has no way of impeaching the expert witness.