Forensic Testimony

Science, Law and Expert Evidence

C. Michael Bowers

• Editorial: Academic Press
• Año: 2013
• ISBN:
  9780123972606
• Categoría: Law
• Categoría: Forensic Science

Forensic Testimony: Science, Law and Expert Evidence —favored with an Honorable Mention in Law & Legal Studies at the Association of American Publishers' 2015 PROSE Awards—provides a clear and intuitive discussion of the legal presentation of expert testimony. The book delves into the effects, processes, and battles that occur in the presentation of opinion and scientific evidence by court-accepted forensic experts. It provides a timely review of the United States Federal Rules of Evidence (FRE) regarding expert testimony, and includes a multi-disciplinary look at the strengths and weaknesses in forensic science courtroom testimony. The statutes and the effects of judicial uses (or non-use) of the FRE, Daubert, Kumho, and the 2009 NAS Report on Forensic Science are also included. The presentation expands to study case law, legal opinions, and studies on the reliability and pitfalls of forensic expertise in the US court system. This book is an essential reference for anyone preparing to give expert testimony of forensic evidence.

• Honorable Mention in the 2015 PROSE Awards in Law & Legal Studies from the Association of American Publishers
• A multi-disciplinary forensic reference examining the strengths and weaknesses of forensic science in courtroom testimony
• Focuses on forensic testimony and judicial decisions in light of the Federal Rules of Evidence, case interpretations, and the NAS report findings
• Case studies, some from the Innocence Project, assist the reader in distinguishing good testimony from bad

Chapter 1

The History of Experts in English Common Law, with Practice Advice for Beginning Experts

C. Michael Bowers, Associate Professor of Clinical Dentistry, Ostrow School of Dentistry, University of Southern California, Los Angeles, CA USA

Abstract

The first chapter provides a brief history of the use of special witnesses in courtrooms. The early expert customs and rules in English Common Law show striking similarity to current rationales. Today the scrutiny of review for expert testimony is much more science based but not devoid of concern in certain areas. The remainder of the chapter develops cases and events involving some forensic disciplines and individual groups that represent examples of forensic challenges, inconsistencies and deficiencies.

Keywords

Expert knowledge; courtroom experts; false testimony; inadequate forensic research; FBI; disavowing bullet lead evidence; hair evidence; Ted Bundy; bite marks

…all the responsibility of medicine, the intricacy of the law and the universality of science. In as much as it carries higher penalties for error than other professions, it is not a matter to take lightly, nor to trust to luck.

Paul L. Kirk

1.1 A brief history of the expert witness in English common law and the relationship to current expert witness practices

The origin of the U.S. legal system is based in the English legal tradition born in the early Middle Ages. The King’s Court of those times determined legal remedies for problems involving crimes, property disputes, and taxation. Experts were also summoned as witnesses but were not considered expert witnesses, as the legal codes did not exist for experts until the end of the 18th century. “Juries of the town” were used in earlier courts as a panel of knowledgeable citizens in matters specific to merchandise and other disputes germane to court proceedings (Golan, 1999). Generally this process was used in large municipalities. Physicians testified in criminal, insurance, and estate cases; surveyors in property cases; merchants in cases concerning the particular practices of their trade; tradesmen in cases concerning the standards of goods; ship builders about the operation and construction of vessels; other artisans based on their respective skillsets; and so on (Rix, 1999). Still, despite a growing presence in the court, the expert witness was not regarded as a distinct legal entity. Another method of the times used witnesses equivalent to an “expert” as “assessors” to the courts.

Unlike court appointed experts or those serving in expert juries, there was no legal procedure to define experts attending court as individual witnesses. A “professional man” who had inspected the facts of the case but not observed events related to a contentious event and who testified to his conclusions was not distinguished from other lay witnesses who often were permitted to testify to their opinion based on direct personal knowledge and observations (Hand, 1901). Thus, in the absence of a particular legal procedure or theory that would define them, experts testifying in court were regarded merely as witnesses. Expert procedure and legal theory on the subject evolved only late in the 18th century as part of a larger transformation of the English legal system that legal historians call the Adversarial Revolution (Golan, 1999). The adversarial system (or adversary system) is a legal system where two advocates represent their parties’ positions before an impartial person (judge or magistrate) or group of people who attempt to determine the truth of the case. The judge rules on allowing or disallowing evidence and witnesses offered by both sides and administers the law and instructions for the juries both during the trial and after (during jury deliberations on the verdict).

The King’s Court, in its later transformation into geographical judicial entities, does show the use of expert testimony in the later 18th century. You can be assured that “science” or “forensics” were unknown at the time for use as a foundation for opinion. However, expert testimony was a significant departure from the courts only admitting a witness who had personal knowledge of facts, events, or personal opinions. It was the seed which led to future change. Much later, in the 20th century, expert opportunities mushroomed into common occurrences in civil and criminal proceedings in the U.S. and abroad. The “expert witness” is allowed to expound and deliberate on probabilities and causation of events and analyses of the physical world that is deemed “outside the ken” of members of the jury and the judge. It is now a powerful tool that can change the scope of and issues present in forensic cases involving financial gain and loss, the breach of contractual obligations and damages, criminal convictions, and dismissal or exoneration of charges for serious offenses and crimes. However, the effects of experts in the U.S. are two-sided, as the adversarial system in its courts commonly presents opposing experts who present opinions based on “science” regarding physical evidence. One should understand that “science” is human-based knowledge subject to human foibles and attitudes. It is the responsibility of those presenting themselves as knowledgeable in certain fields to present proof of their opinions that follow the scientific method rather than only being based on assumptive opinion.

Looking back at the earlier days of this form of “legal expertism” in courts, it is enlightening to trace the thread of the court’s expectations of obtaining a balanced representation of reliable facts via the use of expert opinion. The courts regarded (and still do regard) this type of testimony as a privilege that carries a responsibility for experts in their relationship to the courts.

Prior to the end of the 18th century, courts were ruled completely by the judge in regards to evidence review, presentation of witnesses, and direct and cross-examination. Lawyers were limited in their actions and their objections to decisions and the course of the proceedings. The birth of the English adversarial system, as mentioned above, changed this course to one much more familiar in the present day. The courts began to recognize specific courtroom controls for expert opinion being introduced as evidence. The lawyers embraced this opportunity by addressing their objections and limits to the content and form of witness evidence through the hearsay rule, proofs of reliability, and relevancy of opinion evidence.

The hearsay rule attempts to limit testimony to information based solely on personal observation. The opinion doctrine seeks to control the form in which witnesses communicate their observations and conclusions to the jury, requiring them not to use inferences (opinions derived from their experiences) where the subject matter relates to factual statements (i.e., “the car ran the red light”). The courts, already practiced in admitting a form of expert knowledge in legal proceedings, sought to carve exceptions to continue allowing experts to assist in the questions presented in cases.

These new rules to restrict testimony eventually fit expert witnesses into their own special role. Some call this an expert “exception” to the general rules, but the inherent purpose of the courts is clear. The expert who did not have to personally observe events was needed to explain events in clear language and enlighten the courts in numerous inquiries into areas of special knowledge. This outcome took the experts away from “court helpers” and into the realm of the lawyers representing both sides of courtroom disputes. The era of an “impartial expert” evolved (or devolved) into experts battling each other in court. Today’s judicial “thresholding” or “gatekeeping” of the court testimony of opposing experts was seen back in 1782 in the following classic English law case, which is the cornerstone of the role of the solo expert as an adversarial “entity” (Hand, 1901).

Lord Mansfield ruled in the case of Folkes v. Chadd (1782). A harbour had decayed, and the question was whether it had anything to do with the demolition of a sea-bank erected to prevent the sea overflowing into some meadows. The defendants (owners of the sea-bank) brought in an expert named Smeaton. The plantiffs (the harbor owners) objected and focused on not expecting this strategy and being “surprised at his doctrine and reasoning.” The trial judge excluded the defendant’s expert who then appealed to the “Royal Judges of the King’s Bench” about the booting of their engineer. The appellate court granted a new trial. Lord Mansfield (Chief Justice of the Royal Bench) determined the ruling on the trial court’s excluding Smeaton. The Chief Judge admitted that Smeaton was giving opinion evidence, but he reasoned, the entire case was based on opinion.

“It is objected that Mr Smeaton is going to speak, not to facts, but as to opinion. That opinion, however, is deduced from facts which are not disputed; the situ- ation of banks, the course of tides and of winds, and the shifting of sands. His opinion, deduced from all these facts is that, mathematically speaking, the bank may contribute to the mischief, but not sensibly. Mr Smeaton understands the construction of harbours, the causes of their destruction and how remedied ... I have myself received the opinion of Mr Smeaton respecting mills, as a matter of science. The cause of the decay of the harbour is also a matter of science, and still more so, whether the removal of the bank can be beneficial. Of this, such men as Mr Smeaton alone can judge. Therefore, we are of the opinion that his judgment, formed on facts, was proper evidence.”

These statements from Lord Mansfield indicate what he considered the value of Mr. Smeaton’s participation in the court proceedings. This value superseded the opposing counsel’s objection to Mr. Smeaton’s testimony. Lord Mansfield’s statements can be summarized:

1. Mr. Smeaton had scientifically studied the subject.

2. Mathematics assisted Mr. Smeaton’s testimony.

3. The expert was known to the judge from previous cases.

4. His certainty of the causal connection with the effects of the bank and its potential removal from the harbor was couched in the relative term “may have.”

5. His testimonial evidence was derived from facts, not assumptions.

1.2 Other legal concepts about experts derived from English case law

Additional cases from early English cases provide emphasis to the necessities of being an expert witness in court.

The witness must have adequate knowledge of and skills relating directly to the evidence.

An early case tested the abilities of a lawyer who had previously determined handwriting characteristics of wills and other legal documents. A policeman’s determination about the effects of alcohol is another example. The Court of Appeal ruled that:

The test of expertness, so far as the law of evidence is concerned, is skill, and skill alone, in the field of which it is sought to have the witness’s opinion. I adopt, as a working definition of the term ‘skilled person’, one who has by dint of training and practice, acquired a good knowledge of the science or art concerning which his opinion is sought. It is not necessary, for a person to give opinion evidence of a question of human physiology, that he be a doctor of medicine (Rix, 1999).

This rings true for some but not all aspects of expert opinion. Sadly, the line is blurry regarding where the threshold might really exist for admissibility of opinion simply based on experience with some aspects of criminal investigation or knowledge of a related science. The judicial answer commonly is to accept the testimony over opposing counsel’s objection but somehow limit the “weight” or influence it can have on the jury’s interpretation of events or decisions . A common objection to more aggressive...