Forensic Epidemiology

Principles and Practice

Michael Freeman, Maurice P. Zeegers, Michael Freeman, Maurice P. Zeegers

• Publisher: Academic Press
• Year: 2016
• ISBN:
  9780124046443
• Topic: Jura
• Subtopic: Forensik

It is an inescapable fact that causation, both generally (in populations), and specifically (in individuals), cannot be observed. Rather, causation is determined when it can be inferred that the risk of an observed injury or disease from a plausible cause is greater than the risk from other plausible causes. While many causal evaluations performed in forensic medicine are simplified by the fact that the circumstances surrounding the onset of an injury or disease clearly rules out competing causes (eg, a death following a fall), there are many cases that present a more complicated picture. It is these types of investigations, in which an analysis of comparative levels of risk from competing causes is needed to arrive at a reliable and accurate determination of the most likely cause, that forensic epidemiology (FE) is directed at.In Forensic Epidemiology, the authors present the legal and scientific theories underlying the methods by which risk is used in the investigation of individual causation. Methods and principles from epidemiology are combined with those from a multitude of other disciplines, including general medicine, pharmacology, forensic pathology, biostatistics, and biomechanics, inter alia, as a basis for investigating the plausibility of injury and disease exposures and mechanisms. The ultimate determination of the probability of causation (PC) results from an assessment of the strength of association of the investigated relationship in the individual, based on a comparison between the risk of disease or injury from the investigated exposure versus the risk of the same disease or injury occurring at the same point in time in the individual, but absent the exposure. The principles and methods described in Forensic Epidemiology will be of interest to those who work and study in the fields of forensic medicine, epidemiology, and the law.

• Historical perspective on how epidemiologic evidence of causation has been used in courts in the US and Europe
• Theory and science underlying the use of risk to assess individual causation
• Primer on epidemiologic methods, and various measures used to arrive at individualized comparative risk assessments and PC
• The use of statistical methods applied to publicly available data for ad hoc analysis of PC applicable to the specific circumstances of a case
• Background on complementary disciplines, including forensic pathology, death investigation, biomechanics, and survival analysis
• Examples of applied FE in the investigation of traffic injury and death, automotive and other product defect litigation, medical negligence, and criminal prosecution and defense

Part I

Principles of Forensic Epidemiology

Outline

Chapter 1. Legal Considerations of Forensic Applications of Epidemiology in the United States

Chapter 2. Epidemiologic Evidence in Toxic Torts

Chapter 3. Methods Used in Forensic Epidemiologic Analysis

Chapter 4. Causation in Epidemiology and Law

Chapter 5. The Role of the Expert Witness

Chapter 1

Legal Considerations of Forensic Applications of Epidemiology in the United States

Alani Golanski Weitz & Luxenberg, P.C., New York, NY, United States

Abstract

The history of legal standards for admissibility of epidemiologic testimony regarding causality in US courts is reviewed in this chapter, including the Frye and Daubert standards, among others. The use of the Hill criteria as a framework for assessing the general acceptance of the methods used in an individual analysis is discussed, as is the potential pitfalls of the 2.0 comparative risk ratio threshold used in many jurisdictions.

Keywords

Bradford Hill criteria; Daubert v. Merrell Dow Pharmaceuticals; Federal rules of evidence; Frye v. United States; General Electric Co. v. Joiner, Inc.; Kumho Tire Co. v. Carmichael

Outline

Historical Context of the Frye Standard 3

Prelude to the Federal Rules of Evidence 5

Enter the Federal Rules of Evidence 7

The Judicial Divide Interpreting the Federal Rules of Evidence 7

Daubert 10

Joiner 12

Kumho 13

The Amended Federal Rules of Evidence 13

Daubert Jurisprudence Has Impacted the Frye Analysis 14

The Evolving Set of Daubert Factors 15

Further Legal Approaches to Forensic Epidemiology 18

Conclusion 19

Endnotes 20

Historical Context of the Frye Standard

By the final decades of the 20th century, the two-page opinion in Frye v. United States,¹ issued in 1923, largely defined the way in which state and federal courts treated the question of the admissibility of scientific and technical proof. The specific issue in that second-degree murder case was whether exculpatory expert testimony about the result of Frye's “systolic blood pressure deception” test (precursor to the polygraph machine) ought to have been allowed. In ruling it inadmissible, the Court of Appeals for the District of Columbia Circuit set forth its famous standard:

Just when a scientific principle or discovery crosses the line between the experimental and demonstrable stages is difficult to define. Somewhere in this twilight zone 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.²

Before Frye, most courts handled the problem of whether to trust experts by asking only about the expert's qualifications and whether the subject matter of the testimony was beyond the range of knowledge of the average juror. As the New Hampshire high court in Jones v. Tucker stated in 1860: “When a witness is offered as an expert, three questions necessarily arise: (1) Is the subject concerning which he is to testify, one upon which the opinion of an expert can be received? (2) What are the qualifications necessary to entitle a witness to testify as an expert? (3) Has the witness those qualifications?”³

There were no reported decisions involving epidemiological testimony prior to Frye. Indeed, in the late 19th century and well into the 20th century, technical, nonscientific testimony, more so than the scientific, tended to generate admissibility controversies. The expert in Jones v. Tucker was a surveyor, and the court ruled his testimony admissible on the issue of whether “the marks upon the corners” of a property were “ancient.”⁴ Discussing the range of experts whose “superior skill in relation to” various subjects qualified them to testify, the court referred to handwriting experts and “house joiners” (in modern times, construction contractors).

Soon after the Civil War, in a strict liability action arising from injuries caused by a “mischievous deer” that defendant permitted to roam on his property, the US Supreme Court ruled that expert testimony was not needed on the issue of the offending animal's character or disposition, which was “common knowledge.”⁵ The court's survey of the range of expert testimony with which it was then familiar was telling:

Medical men, for example, may give their opinions not only as to the state of a patient they may have visited, or as to the cause of the death of a person whose body they have examined, or as to the nature of the instruments which caused the wounds they have examined, but also in cases where they have not themselves seen the patient, and have only heard the symptoms and particulars of his state detailed by other witnesses at the trial. . . . It must appear, of course, that the witness is qualified to speak to the point of inquiry, whether it respects a patented invention, a question in chemistry, insurance, shipping, seamanship, foreign law, or of the habits of animals, whether feroe naturoe or domestic.⁶

That pre-Frye controversies, under the two-part special knowledge/qualifications test, would tend to involve witnesses offering technical rather than scientific testimony is understandable. On the one hand, scientific knowledge is more clearly beyond the ken of the average juror; technical understanding fell closer to the divide between the ordinary citizen's common knowledge and the specialist's enhanced awareness. On the other hand, the marketplace could more readily attest to the expertise of scientific specialists, since they would be cloaked with an established professional status; their success in their profession corroborated their expertise.⁷

Even in the case of scientific experts, however, the issue of the expert's qualifications was seen in relation to the nature and quality of competing expertise in the case. Courts viewed even scientific expert testimony with some degree of suspicion, and required that any such testimony pass through the prism of necessity. For example, in the medical malpractice case of Martin v. Courtney,⁸ the Minnesota Supreme Court overturned the jury's verdict in favor of the plaintiff, unfavorably comparing the qualifications of the plaintiff's expert, a surgeon who had graduated from medical school less than 5 years before trial, to those of the defendant physician, who had 15 years of experience and had been chief surgeon at his hospital.⁹

In general, however, courts in the pre-Frye period attempted to answer the question posed in Jones v. Tucker as did the Supreme Court of Errors of Connecticut in Taylor v. Town of Monroe¹⁰:

The true test of the admissibility of such testimony is not whether the subject matter is common or uncommon, or whether many persons or few have some knowledge of it, but whether the witnesses offered as experts have any peculiar knowledge or experience, not common to the world, which renders their opinions founded on such knowledge or experience any aid to the court or jury in determining the questions at issue.¹¹

Such was law's outlook in the decades preceding Frye. Nor have these twin requisites to the admission of expert testimony—(1) the expert's qualifications to render testimony in an area of particular expertise and (2) the need for any such testimony to assist the fact finder—lost their urgency in modern times. The explanation for this begins with the constitutional right to a trial by jury possessed by criminal defendants and civil litigants. The Sixth Amendment provides, inter alia, that criminal defendants have the right to “an impartial jury of the state and district wherein the crime shall have been committed…. .”¹² Similarly, the Seventh Amendment guarantees trial by a jury of one's peers in “suits at common law, where the value in controversy shall exceed twenty dollars….”¹³ State constitutions afford local litigants analogous rights.¹⁴

Against the backdrop of the jury trial rights afforded by the US Constitution as well as parallel state constitutional provisions, the legal system has always recognized the importance of adopting procedures and evidentiary doctrines that avoid intruding upon, or usurping, the jury's role. Witnesses presented to the jury as “experts” come cloaked in auras of authority¹⁵ and reliability.¹⁶ Therefore, expert testimony in areas accessible to the ordinary juror's common sense and everyday experience would tend to muscle out the jury's fact-finding function. For a similar reason, an expert witness's proffer of a legal conclusion has traditionally been deemed impermissible.¹⁷

Prelude to the Federal Rules of Evidence

The federal court's decision in Frye went largely unnoticed for several decades. When courts cited to Frye, they tended to do so on the narrow issue in that case, namely, the admissibility of “lie detector” evidence,¹⁸ or of evidence concerning the findings associated with similar mechanical devices.¹⁹

Also during the decades following Frye, various attempts at drafting a comprehensive set of evidentiary rules were unsuccessful. These included efforts by the Commonwealth Fund Committee in 1927 and by the American Law Institute in 1942.²⁰ Nevertheless, in 1961, the Judicial Conference of the United States approved the c...