2.1: Scientific Methodology

A quick search of the internet will produce several good definitions of scientific methodology. Let us take a look at just a few:

• An empirical method for acquiring knowledge
• A systematic and rigorous process
• A method to discern activities by which success is achieved
• A method to discern activities by which success is achieved
• Experimentation used to explore observations and to answer questions

Your author thinks that all these definitions apply to some degree, but to truly understand scientific methodology for forensic sciences, one must understand the hallmark court cases that have been instrumental in forming the foundation of the methodologies as they apply to each discipline of the forensic sciences. Those cases are Frye v. United States 293 U.S. F.1013 (1923), Daubert v. Merrell Dow Pharmaceuticals 509 U.S. 579 (1993), and Kumho Tire Company v. Carmichael 526 U.S. 137 (1999). These court decisions shaped modern scientific methodology in the field of forensics because of the application of forensic science to assist the court with determining the innocence or guilt of a defendant who is accused of a crime.

Frye v. United States 293 U.S. F.1013 (1923)

In November 1920, Dr. R. W. Brown, a well-respected African American physician, and the President of the National Benefit Life Insurance Company, was shot through the head in his house in Washington D.C. A .45-calibe revolver was found next to the body of Dr. Brown. Although there were no witnesses to the crime, a house guest recalled allowing a male visitor into the house late in the evening before the sound of gunshots were heard. The house guest, Dr. Julian Dabney Jackson, described the man as being in his mid-20’s, light brown skin, weighing approximately 135lbs. There were few clues as to the identity of the man, but instigators did find fingerprints on the exterior brick wall of the house. In August 1921, James Alphonzo Frye was arrested for forgery on a government compensation check. During an interrogation, Mr. Frye confessed to the forgery, a robbery of a salesman, and the murder of Dr. Brown, which he said was in self-defense after Dr. Brown hit him in the head. While awaiting trial, he was visited in jail by his court appointed attorneys, Richard Mattingly and Foster Wood. During the visit, Mr. Frye retracted his confession and said the only reason he had made the confession was to split a $1,000.00 reward, that had been offered by the family of Dr. Brown for the apprehension and conviction of the murder, with Sergeant Jones, the detective who conducted the interview. Mr. Frye also claimed that the detective had promised to drop the robbery charge if he confessed to the murder. Mr. Frye was charged with murder in the first degree with the prosecution seeking the death penalty.

The attorneys were convinced of his innocence, but they had a few problems: He matched the description provided by Dr. Jackson, he did not have an alibi for evening, and they could find no proof that Sergeant Jones had collected the reward money. They decided to turn to Dr. William Moulton Marston, a psychologist who in 1915 had discovered a means by which a person could be shown to be either lying or telling the truth based on their blood pressure. The device was called the systolic blood pressure deception test. The test was administered at the jail before the trial commenced. Dr. Marston was convinced that Mr. Frye was telling the truth that he had provided a false confession to the detective. A jury trial was held in 1922. At the trial, Presiding Justice McCoy excluded the results of the lie detector test, although it was well-known to the jury that the test had been performed. Justice McCoy had allowed the testimony of psychologists in previous trials, but the lie detector test was, “Not yet a matter of common knowledge,” as reported by Ken Alder in his book The lie detectors: The history of an American obsession (2007). Mr. Frye was convicted of murder but, possibly owing to the knowledge of the lie detector test, the conviction was in the second degree, and he was sentenced to life in prison.

In 1923, the case was appealed to the District of Columbia Court of Appeals. At issue was the exclusion of the lie detector test at the jury trial. Associate Justice Van Orsdel demonstrated an understanding of the science behind the blood-pressure lie detector test and acknowledged the importance of testimony by persons who are experts in their field of study or have knowledge above that of the ordinary person; however, in his ruling he stated, “ Somewhere in this twilight zone (between experimental and demonstrable stages of discovery) the evidential force of the principle must be recognized, and while courts will go a long way in admitting expert testimony deduced from a well-recognized scientific principle or discovery, the thing from which the deduction is made must be sufficiently established to have gained general acceptance in the particular field in which it belongs.” The appeal was denied, and the finding of the trial court was upheld. In this case, Justice Van Orsdel, while acknowledging the need for expert witnesses, planted the seed for scientific methodology to separate a science that was generally accepted by the scientific community and a science that was not, and later to be called “Junk science.”

Your author recommends reading the entire appellate court decision in Frye v. United States 293 U.S. F11013

Federal Rules of Evidence, Section 70

In 1975, in an effort to refine and expand the admissibility of scientific expert witness testimony first established by the Frye v. United States (1923) standard, the United States Congress created Section 702 of the Federal Rules of Evidence. It should be noted that the Federal Rules of Evidence were created following the recommendations of a special advisory committee appointed by the United States Supreme Court in 1965. Rule 702 established that the testimony was admissible if it could ‘assist the trier of fact to understand or determine a fact in issue.’ Furthermore, the trial judge could qualify an expert witness by their knowledge, skill, experience, training, or education. Also, unlike Frye, an expert witness could testify to their opinion. Interestingly, the rule did not require a science to be generally accepted by the scientific community. Of course, Section 702 has been enhanced over the years, as recently as 2023, which have brought it closer to the United States Supreme Court ruling set forth in the Daubert Decision of 1993.

Your author recommends the reader to explore Rules of Evidence, Section 702 in its current iteration.

Daubert v. Dow Merrell Pharmaceuticals 509 U.S. 579 (1993)

In 1992, the parents of two infants, Jason Daubert and Eric Schuller, who were born with defects, sued Merrell Dow Pharmaceuticals, alleging that the prescription medication Bendectin, used to treat nausea and vomiting during pregnancy, had caused deformities. The civil lawsuit was held in a California District Court. During the trial, the petitioners provided expert witness testimony that reflected experiments conducted in vivo and in vitro using laboratory animals, and the subsequent supporting pharmacological research papers, linked the drug to the birth defects. Merrell Dow Pharmaceuticals presented their own research that was conducted on human volunteers, which proved the drug did not cause birth defects. Furthermore, Merrell Dow also successfully argued that the studies that were conducted on laboratory animals were not generally accepted by the scientific community. Merrell Dow Pharmaceuticals requested the case be transferred to the Federal courts and requested a summary judgement, which was granted. The petitioners appealed to the Ninth Circuit Court of Appeals, which upheld the lower court ruling using the Frye v. U.S. decision and Rule 702 standard. The Ninth Circuit Court of Appeal went further to suggest that the research conducted for the petitioner was done so solely for the purpose of litigation. Following this decision, the petitioners sought relief from the United States Supreme Court.

Following much deliberation regarding the acceptance of expert witness testimony, the Frye v U.S. decision versus Rule 702, the U.S. Supreme Court issued a unanimous ruling to remand the case back to the lower court to re-examine its finding using Rule 702 and not the Frye standard in what is now known as the landmark Daubert Decision. The lower court did so and upheld its decision in favor of Merrell Dow Pharmaceuticals. The significance of the Daubert Decision is that the highest court in the country supplanted the Frye ruling with Federal Rule 702 as the standard for the admission of expert witness testimony. The court went further to invest the trial judge with “gatekeeping responsibility” for allowing scientific expert witness testimony. The court provided guidelines by which the trial judges would determine the admissibility of expert scientific witness testimony.

First, remember that Federal Rule 702 requires that the evidence or testimony "assist the trier of fact to understand the evidence or to determine a fact in issue." Therefore, the testimony must be relevant to the crime being charged and must be an aid to understanding the facts of the case.

Second, in the unanimous opinion, Justice Blackmun wrote, ‘in order to qualify as "scientific knowledge," an inference or assertion must be derived by the scientific method. Proposed testimony must be supported by appropriate validation-i. e., "good grounds," based on what is known. In short, the requirement that an expert's testimony pertain to "scientific knowledge" establishes a standard of evidentiary reliability.’ Therefore, the science must follow an approved methodology.

Third, Justice Blackmun wrote, ‘Scientific methodology today is based on generating hypotheses and testing them to see if they can be falsified; indeed, this methodology is what distinguishes science from other fields of human inquiry.’ Thus, the science must be based on repeatable experimentation.

Fourth, Justice Blackmun wrote, ‘another pertinent consideration is whether the theory or technique has been subjected to peer review and publication.’ If you remember from Chapter 1 that your author mentioned the Journal of Forensic Identification by the International Association for Identification and the Journal of the Association for Crime Scene Reconstruction. These are excellent sources where these scientific studies and experiments can be published. Furthermore, these, and other associations, maintain scientific principles and practices working groups where established and new experiments and methodologies are subjected to peer review.

Finally, the opinion states, ‘Additionally, in the case of a particular scientific technique, the court ordinarily should consider the known or potential rate of error.’ Fortunately, the court left some wiggle room on this requirement by not making it a mandatory requirement but instead chose the word ‘ordinarily.’ In the forensic sciences, it is often difficult to establish an error rate.

In summary, the rules that need to be followed for scientific testimony to be allowed are:

• The science must be relevant to the case being tried and must be helpful in understanding the facts
• The science must follow a methodology
• The science must be generally accepted by the scientific community
• The science must be based on repeatable experimentations
• The scientific experiments must be published and subject to peer review
• Ordinarily, the error rates of the experiments should be known

Daubert helped establish the rules for expert scientific courtroom testimony, but there were issues that needed to be resolved, which included a defense challenge that a forensic practitioner was not a scientist and therefore could not provide testimony on scientific matters. Fortunately, Kumho Tire v. Carmichael 626 U.S. 137 was not far away.

Your author recommends the reader listen to the oral arguments in Daubert v. Merrell Dow Pharmaceuticals 509 U.S. 579 (1993), which can be found on the internet.

Kumho Tire Company v. Carmichael 526 U.S. 137 (1999)

On July 6, 1993, Patrick Carmichael was driving his minivan when the right tire of the vehicle had a blow-out. Patrick lost control of the van, and it overturned causing death to one passenger and serious injuries to the others. Patrick Carmichael, the survivors of the accident, and the family of the decedent brought suit in the United States District Court for the Southern District of Alabama against the Kumho Tire Company alleging a defect in the tire caused the accident. The attorneys for the plaintiffs relied heavily on the testimony of Dennis Carlson, Jr., a tire failure specialist who was a former tire manufacturing engineer with ten years of experience at Michelin America Tire Company and who possessed a master’s degree in mechanical engineering. Mr. Carlson intended to testify that a design defect in the tire had caused the accident based on a visual inspection he had made of tire, and upon his theory that the failure of the tire was due to the manufacturing design defect and not the result of improper maintenance or abuse of the tire. Attorneys for Kumho Tire argued that Mr. Carlson’s analysis was incorrect and that his testimony failed to be supported by the Federal Rule of Evidence, Section 702. The trial court agreed, and the testimony was excluded, and summary judgement was given to the defendant, Kumho Tire Company. The plaintiffs appealed the decision to the Eleventh Circuit Court of Appeals, which reversed the decision of the district court based on the requirements set forth in the Daubert Decision.

Kumho Tire Company petitioned the United States Supreme Court to review the appellate court decision. Arguments were heard in 1998, and a decision was rendered the following year which overturned the appellate court decision and reinstated the district court ruling. The Supreme Court determined that the trial court appropriately upheld the roll of a “gatekeeper,” as described in the Daubert Decision, and, most importantly, that this obligation applied towards all expert testimony, not just scientific testimony. The trial court’s decision to exclude Mr. Carlon’s testimony was appropriate with the discretion given to the trial judge.

Although the testimony of an expert witness, who had provided testimony in previous tort cases, was excluded by the ruling of the trial court and the United States Supreme Court, indirectly, the highest court in the country extended the responsibility of the trial judge to ensure all expert witness testimony remained relevant and reliable to the matter being litigated, and this responsibility included testimony that was ‘technical’ in nature, or was of ‘other specialized knowledge,’ and not just scientific in nature.

Your author recommends reading Karl Thorvold’s "Guarding the Gate to Expert Testimony: Kumho Tire Co. v. Carmichael and Statev. Council," South Carolina Law Review: Vol. 51 : Iss. 4 , Article 16.