American Journal of Law & Medicine

Adversarial medical and scientific testimony and lay jurors: a proposal for medical malpractice reform.


Pleas for reform of the legal system are common. One area of the legal system which has drawn considerable scholarly attention is the jury system. Courts often employ juries as fact-finders in civil cases according to the Seventh Amendment of the Constitution: "In Suits at common law, where the value in controversy shall exceed twenty dollars, the right of trial by jury shall be preserved...."(1) The general theory behind the use of juries is that they are the most capable fact-finders and the best-suited tribunal for arriving at the most accurate and just outcomes.(2) This idea, however, has been under attack, particularly by those who claim that cases involving certain difficult issues or types of evidence are an inappropriate province for lay jurors who typically have no special background or experience from which to make informed, fair decisions.

The legal system uses expert witnesses to assist triers of fact in understanding issues which are beyond their common knowledge or difficult to comprehend. In cases involving medical and scientific issues, courts rely heavily on the use of expert witnesses. The use of these experts, however, can pose special problems for jurors. Our legal system operates on the premise that the best way to uncover the truth is to place the disputing parties in an adversarial posture; frequently, the result is a "battle of the experts" with opposing sides providing expert witnesses who testify in support of their respective positions. Lay jurors may be placed in the unsettling position of having to determine which expert to believe while they themselves lack clear understanding of the testimony. Critics argue that under these circumstances, jurors are ill-suited to render accurate judgments.(3)

There are three possible avenues for reforms directed toward solving this problem: the adversary system, the use of expert witnesses, and the jury system. With respect to the adversary system, lawyers (and sometimes judges) are accused of exploiting the adversarial process to inappropriately influence juror decisions.(4) Experts have been condemned as "hired guns" whose biased opinions are motivated by financial considerations.(5) Probably the most scathing attack, however, has been directed at the jury. Jurors are perceived as incompetent, partial, and capricious decision-makers who are a threat to the proper administration of justice.(6)

Concerns about juror competency are particularly acute in cases involving medical testimony because these cases often require sophisticated understanding of medical practice or specific knowledge of complex human physiological processes.(7) These concerns have prompted a great deal of discussion about tort reform, especially in the area of medical malpractice.(8) As such, this context will form the basis for the analysis in this Note.(9)

This Note will analyze the jury system's handling of expert witness testimony on medical and scientific issues to assess the validity of criticism of juries, to review and evaluate the reform proposals offered by scholars who have examined this problem, and to arrive at potential solutions which could better serve the accuracy and fairness goals of the legal system in cases involving complex medical testimony. Part I will provide background to this issue, including criticism of the major participants in cases involving medical testimony. Part II will examine several of the approaches reformers have suggested to avoid or eliminate these problems for the jury. Finally, Part III will outline a proposal for how cases involving medical testimony might be best handled.



The principle function of the jury is to resolve disputes which the parties have been unable to settle between themselves. Juries do this by making factual determinations and by applying relevant legal principles-- explained by the judge--to the facts." The philosophy behind the modern jury system is that disputes are best resolved by impartial citizens who can render judgments which reflect their common experience and represent community values.(12) Years ago, it was assumed that juries should have some special knowledge or expertise about the cases they decided.(13) Now, however, ideal jurors are seen as impartial laypersons--"blank slates" who do not have preconceived ideas or opinions, but "become[] filled with only that information entered into evidence."(14) But this view has been attacked by such scholars as Professor Steven Friedland who argues that this notion of the jury is antithetical to the goals of informed, competent, well-reasoned decision-making.(15) Under this conception, common sense leads to the conclusion that the more knowledge and experience a person possesses about a subject, the more capable that person is of rendering a wise judgment.

Opinion about the value of the civil jury is sharply divided. Some commentators have expressed the view that juries are actually quite good at deciding cases (except for, perhaps, following judicial instructions.(16) As support, they commonly cite past studies which show substantial verdict agreement between judges and juries.(17) Some research also demonstrates that individual jurors who draw inaccurate factual conclusions tend to correct each other during the deliberation process, and the failure of individual jurors to recall facts or instructions is solved by jurors' pooling their recollections.(18) Studies have also shown that juries generally take their role seriously and sincerely want to make the best judgments.(19) In addition, proponents of the jury system have ascribed "special virtues" to the jury, such as providing "individualization of justice" and promoting social and political values through citizen participation.(20) These benefits of the traditional jury system are significant and should not be discounted lightly, even though juries are sometimes criticized for their handling of difficult cases.(21) Others, more skeptical of jury decision-making, note problems of bias which can hinder accurate judgments. Cognitive biases of jurors, including a hindsight bias (22) and sympathy for an injured plaintiff, color jurors' ability to arrive at impartial verdicts.(23) Jurors are notorious for being susceptible to emotional ploys and other legally irrelevant arguments.(24)

Another basic criticism of jurors is that because the large majority of jurors have no formal legal training or legal knowledge, they lack the ability to understand and apply the law to the facts. This idea is supported by empirical data which demonstrate that juries are not as skillful at interpreting and applying legal rules as they are at determining facts.(25) Juries are faulted for failing to follow judicial instructions.(26) The problem is most often not that the jury ignores the law, but that the law is difficult for jurors to understand. For instance, "the standard of care for negligence is extremely vague; it is often hard to determine what the standard [of care] is, much less whether it has been breached. Consequently, in many cases the jury is, in a sense `guessing' when it renders a verdict."(27) It is unfair to criticize jurors for not applying the law unless the law is explained so that they may understand it.(28)

Even those who are generally enthusiastic about juries are less confident about juror competence in cases with complex, adversarial medical or technical evidence.(29) Some suggest that when jurors lack knowledge of a subject, they will disregard evidence about it and focus instead on personal attitudes or preconceived assumptions."' For example, jurors "may be tempted to resolve issues on the basis of the expert's demeanor or credentials because they lack the expertise necessary to evaluate the validity of substantive scientific evidence."(31) Others fear that jurors' inexperience with certain issues will cause them to overvalue the opinion of a possibly biased expert witness.(32)

Although no firm consensus exists about jury competence in these cases,(33) most critics retain some faith that jury decision-making in cases involving complex issues can be improved through procedural innovations.(34)

B. The Adversarial System

The American legal system operates under the assumption that the best way to elicit information and discover the truth is through vigorous advocacy by adverse parties. Juries then face the task of assessing the credibility of the testimony presented by each side. For ordinary witness testimony, this may be an effective way to reach decisions. In cases requiring expert testimony, the consequence of this system is that each side produces an expert to testify on its behalf in support of its theory of the case. Assessing the credibility of testimony of conflicting expert witnesses may be extremely difficult for lay jurors who have no general knowledge of the field to guide their judgments about which expert's version seems correct; having "partisan experts ... frequently operates to confuse the ... jury rather than to inform."(35) This problem leads to further concerns about juror competency.

Juries, however, are not the only participants subject to criticism due to the adversary system. The experts themselves have been publicly perceived and decried as "hired guns" who "find it financially or otherwise profitable to leave ethics aside and provide whatever testimony may be needed."(36) The adversarial system, it is argued, puts pressure on experts to exaggerate or distort their testimony to support the position of those who retained the expert.(37) Historically, medical experts have disdained their role in the courts and maligned their peers for their participation as expert witnesses, especially when testifying against another doctor.(38) This has led to a "difficulty in obtaining skilled experts who are willing to testify against colleagues."(39) Furthermore, experts are criticized for being prone to the same cognitive biases, including outcome bias and sympathy bias, as jurors.(40) It follows that if jurors are relying on experts with skewed opinions, this is likely to exacerbate the problems they already face in evaluating the testimony.

Lawyers and judges also suffer complaints for their roles in the adversary system and, in particular, for their interactions with juries. Lawyers are accused of manipulating and abusing the adversarial system and capitalizing on the inexperience and relative ignorance of jurors.(41) Lawyers knowingly choose experts to testify whose views are ill-regarded.(42) Lawyers take advantage of the legal process to drag out already lengthy trials; this hinders accurate verdicts because jurors tend to experience memory problems when serving on a lengthy case. …

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