The Journal of Philosophy, Science & Law

Manuscripts and Articles

Volume 1, November 2001

“The Evolving Role of Scientific Experts in the Courts”*

Mark S. Frankel**


*Based on an invited lecture at Hillsdale College, September 14, 2000.

**Director, Program on Scientific Freedom, Responsibility and Law American Association for the Advancement of Science


Criticism of the way the courts have handled--or mishandled--cases that have involved complex scientific and technical evidence has received extensive coverage in the press. One might argue whether such coverage has exaggerated the problem, but it nonetheless has created a degree of uneasiness with our judicial system. As the distinguished members of the Carnegie Commission on Science, Technology and Government reported several years ago, "If these claims go unanswered, or are nor dealt with, confidence in the judiciary will be undermined as the public becomes convinced that the courts…are incapable of correctly resolving some of the most pressing legal issues of our day."[1] Part of this problem does rest with the judiciary, but part lies with scientists and engineers as well. If the integrity and image of science in the courtroom is to be enhanced, at least two things have to happen. One, the courts need to improve their ability to assess scientific and technical evidence; and two, there needs to be a way for scientists and engineers to provide their expertise without having to compromise their objectivity and ethics.

Why is science and engineering increasingly important in the legal system? First, there the increasing presence of scientific and technical matters in civil and criminal litigation means that the legal system requires the best science in order to make rational decisions. Second is the singular critical role that scientific evidence may play in certain types of cases. For example, in cases the rest on whether or not exposure to a chemical led to crippling medical condition, science might be used to answer the question of causation. For the parties, the failure to secure the admissibility of their expert scientific evidence could mean the difference between winning and losing. Third, as many death row cases indicate, science can play a critical role in life and death decisions made by our judicial system (e.g., DNA fingerprinting). Fourth, the economic stakes are high. Companies have filed for bankruptcy during the course of litigation; high tort awards to plaintiffs can lead to higher consumer costs; and companies may avoid innovation because of the risks associated with litigation, thereby denying consumers new products. And fifth, there is a real danger that public confidence in the judicial system and in the credibility of science is threatened by the way that legal system deals with scientific and technical issues. This is manifested by the expert as “hired gun” phenomenon and the public perception that the legal system does not do an effective job of distinguishing between the Nobel Laureate and charlatan.

It is fair to say that there is plenty of blame to go around. The point is that the courts are seen as not having performed adequately in the way they have handled scientific and technical information, and this mishandling has been blamed for outrageous tort awards and improper criminal convictions.

The issue of science in the courtroom has been addressed by a series of three Supreme Court decisions since 1993. They are Daubert v. Merrell Dow Pharmaceuticals, Inc., 509 U.S. 579 (1993); General Electric Co. v. Joiner, 522 U.S. 136 (1997); and Kumho Tire Co. v. Carmichael, 526 U.S. 137 (1999).

These three cases focused on the use of scientific and engineering-based evidence in federal court. Essentially, they instruct federal judges to act as gatekeepers in deciding whether to admit scientific evidence, including expert testimony, into legal proceedings. Judges are expected to inquire into the reasoning and methodology of underlying science and engineering testimony, and into connection between evidence/testimony presented and conclusions drawn by expert.

To put it succinctly, judges are asked to consider three basic questions:

  1. Is testimony based on established scientific or engineering principles?
  2. Are methods used appropriate to the task at hand and applied properly?
  3. Is there a logical connection between how the first two questions are answered and conclusions drawn by expert?

There three cases have placed a heavy responsibility on judges. For some, it’s a daunting task, as reflected in these words by a federal district court judge. “I’ve got a background in the humanities. And I’m faced with two equally qualified scientists, one of whom says ‘black’ while the other says ‘white’. Now c’mon, I’m supposed to make a decision here?”[2]

So where can judges turn for help in performing this new gate keeping role? Traditionally, that kind of help in our adversarial system has come from experts hired by parties to the litigation. Virtually every area of law practice uses experts at some point. But for someone genuinely interested in having the most valid and reliable science surface during litigation, the reliance on parties’ experts poses several problems.

  1. Attorneys for both sides only hire experts who will support their position (although some times they will retain other experts just to keep them from being hired by the opposing side). They are interested in finding the “best witness,” not necessarily the best scientists or engineers. This has led to the “hired gun” phenomenon, where people who are willing to testify to marginal or even dubious scientific positions are in great demand and command large fees.
  2. The Federal Rules of Evidence state that the role of the expert is to “assist the trier of fact to understand the evidence…” However, in reality, the adversarial system fosters persuasion over education. Lawyers consider science a tool to further their client’s interests. They will selectively present evidence according to their client’s needs. As one criminal defense attorney has publicly stated, “I may not want the jury to understand the science! It’s my duty to my client to create a reasonable doubt.”[3] In other words, good science might just get in the way.
  3. Following from two is that the adversarial system places great emphasis on discrediting the expert, thereby diverting attention away from the science. When you believe that a judge or jury cannot distinguish between the technical presentations of scientists from the opposing parties, your best legal strategy may be to attack the credentials or alleged biases of the opposing expert.
  4. And following from three is the unfortunate consequence that the best scientists and engineers simply don’t want to have anything to do with the legal system. They do not want to be an expert for one side or the other, either because they don’t believe that the best science will have a chance to surface or because they do not want to expose themselves to the indignities of attacks on their credibility. This is clearly an unsatisfactory situation for a system that increasingly relies on experts as crucial to the administration of justice.

Many of the problems associated with using science and technology in judicial proceedings can be traced to the clash of the two cultures of law and science. Science is not merely a body of knowledge; it is a process for proposing and refining explanations about the world that are subject to further testing. Scientists value precision and accuracy, and seek a high level of confidence in their findings, which may require an extended period of time. The legal system, however, operates with a different set of values and rules than science. It seeks consensus on its version of the truth, that is, pragmatic justice at a particular point in time so that people can get on with their lives. Scientific and technical information is viewed simply as a tool to achieve that end. When scientists enter the legal arena, they are subject to pressures and constraints imposed by the legal system. As a practical matter, their options are limited, and the expert is often caught between the proverbial rock and a hard place. Scientists and engineers are cautioned by their professional ethics not to confuse partisanship with scientific rigor.

But it’s tough to be impartial in the adversary system, where one side recruits you. There are pressures from attorneys who want to make sure that you are on their client’s side. There is a tendency to identify with the side for which one is testifying. And there are expectations associated with receiving a fee—the expert’s expectations as well as those of the client.

Under such pressures, the norm of disinterestedness that is associated with the search for truth in science may be trumped by the rules of the legal system. Experts may find themselves making statements that they would not be comfortable making in a scientific forum. As one court observed, “these witnesses say and conclude things which, in the Court’s view, they would not dare report in a peer-reviewed format.”[4] In the extreme, this can lead to what is termed “litigation science,” or evidence that is produced solely for litigation without any formal peer review.

There may be a way to avoid some of the pitfalls associated with expert testimony—the use of experts appointed by federal judges to serve the court rather than the parties to litigation. This is not a novel idea, having been proposed at least as far back as 1886 in the American Law Review. Judges have the power to appoint such experts through several sources, including the Federal Rules of Evidence cited earlier. Those rules state that “The Court may appoint any expert witness agreed upon by the parties, and may appoint expert witnesses of its own selection.”[5]

There are a number of advantages of court appointed experts. They are not under pressure to tailor their testimony according to partisan lines. They can put partisan testimony into perspective that enlightens rather than confuses. They may be able to neutralize any unfair advantage one side has over the other with more resources to hire experts, creating a more even playing field. They can help to reduce costs and delays precipitated by battle of the parties’ experts by encouraging settlement or by narrowing issues prior to trial so that time is allocated to areas of real scientific controversy. And they may increase the willingness of some of the best scientists and engineers to testify.

Despite these advantages, federal judges have rarely used their authority to appoint experts. 1991 survey[6] by the Federal Judicial Center, the research and education arm of the Judicial Branch, found that of 431 judges responding, only 20% (86) had appointed an expert, and of those that did less than half had done so more than once. But it is worth pointing out that when judges did appoint such experts, they overwhelmingly reported a high degree of satisfaction. And 87% (375) of the judges surveyed expressed the view that court appointed experts are likely to be helpful in some cases.

The notion of court appointed experts is not without its critics. It can be argued that no scientist is truly neutral. If they are expert, then they come to the issues with strong ideas about the science involved, which might tip the balance in favor of one or the other parties. Parties’ attorneys may be reluctant to cross-examine vigorously the court appointed expert for fear of alienating jurors. Court appointed experts place an additional financial burden on the parties since they will likely be saddled with paying the expert’s fees. And no attorney would be pleased with the prospect of encountering a witness who is only accountable to the court.

Despite these criticisms, the primary reason given by judges for not appointing experts is that they don’t know how to find one to meet their immediate needs. The American Association for the Advancement of Science (AAAS) has designed a project intended to meet this need.


Court Appointed Scientific Experts (CASE)—A AAAS Demonstration Project

AAAS has launched a five-year pilot project to enhance the availability of reliable scientific and technical expertise to the judiciary. The project will initially focus only on the federal district courts, in primarily civil cases with a strong scientific or technical component. It will be evaluated by the Federal Judicial Center, the research and education arm of the Judicial Branch. The project will be considered a success if it provides scientific and technical experts in a way that federal judges find useful. Judges are, after all, our clients. On what basis would judges be likely to consider the project useful?

The project was endorsed by Supreme Court Justice, Stephen Breyer, who at the 1998 AAAS Annual Meeting, declared that AAAS has “offered their help. We in the legal community should accept that offer….The result, in my view, will further not only the interests of truth but also those of justice.” In addition, several federal judges were involved in developing the project’s design, and a number are now serving on various project committees.

The project infrastructure includes a Project Advisory Committee, which will provide guidance on the overall structure, objectives, and direction of the demonstration project. The committee will be active in the development of educational materials and the guidelines for conflicts of interest, and will appoint members to subcommittees on education, professional standards, and evaluation. The Advisory Committee will not be involved in the day-to-day operation of the project. Specifically, the committee will have no role in the selection of cases or in the identification and recruitment of experts for these cases.

An Education Subcommittee will oversee efforts to develop educational materials for experts selected by the courts. The materials will assist experts in understanding aspects of the adversarial process, such as discovery and cross-examination so that they can be prepared for their participation in the legal process. Other educational material will be prepared for judges to provide information about the project. In addition to this general material, judges inquiring about assistance in selecting an expert will be given procedural materials, and judges who are appointing a CASE expert will be provided with additional material that could be helpful in managing pretrial and trial proceedings.

A Professional Standards Subcommittee will draft guidelines for conflicts of interest, including questionnaires or other instruments designed to gather pertinent information for use by the courts. In addition to considering questions regarding conflicts prior to appointment, the subcommittee will also address policies relating to permitted professional activities following an expert’s appointment by the court.

An Evaluation Subcommittee will review the evaluation plans prepared by the Federal Judicial Center and advise project staff and the Advisory Committee on the evaluation process.

There will also be a Recruitment and Screening Panel, appointed by staff, which consists of 27 individuals from key scientific and engineering disciplines. These men and women will be well known and respected and, in turn, be acquainted with a great many people in their own field or related areas of research. The panel will have two main roles. The first will be to help identify scientists, engineers or physicians who are highly qualified in the area of expertise sought by a judge who has requested assistance from the project.

Because names of potential experts may come from sources other than panel members – for example, from scientific societies – the panel’s other important role will be to vet the recommended scientists, engineers or physicians for scientific merit, reputation, and the ability to communicate highly technical information to non-scientific audiences.


How The Project Will Work

A court must first contact the project for assistance. If the project accepts the case, staff will determine type of expert(s) needed. Three methods will be employed to identify experts: (1) online databases that have been vetted by others; (2) science and engineering societies and education associations; and (3) the recruitment and screening panel. For every request, we hope to send the court two to four candidates, all of whom will have to complete a “conflict of interest” questionnaire. While we believe we can eliminate from consideration experts with obvious conflicts, it will be up to the court to make final determination of whether a more subtle conflict is disqualifying.

We envision several possible rolls for experts we provide. They could serve as trial witnesses; help to educate judges and juries about the technical issues involved; advise court in pre-trial (admissibility) proceedings, discovery, or settlement phase; and/or assist in the damage or penalty assessment phase.

We believe the project can improve the way scientific and technical information is handled by the courts. At the same time, the project will offer scientists and engineers an opportunity to perform a valued public service. As a result, the integrity and image of both the judiciary and science will be enhanced and, we hope, justice will be better served.


[1] Report of the Carnegie Commission on Science, Technology, and Government, Science and Technology in Judicial Decision Making: Creating Opportunities and Meeting Challenges (New York: Carnegie Commission, March 1993), p. 11.

[2] Judge Carl B. Rubin, U.S. District Court, Ohio. Quoted in Health, January-February 1994.

[3] Gerald Zerkin. Quoted in Beth Baker, “New Project will Provide a Link Between Scientists and the Judiciary,” BioScience, 49:764, October 1, 1999.

[4] Johnston v. U.S., 597 F. Supp. 374 (U.S. District Court, Kansas, November 15, 1984).

[5] Federal Rule of Evidence 706.

[6] Joe S. Cecil and Thomas E. Willging, "Court-Appointed Experts," in Reference Manual on Scientific Evidence(Washington, DC: Federal Judicial Center, 1994), pp. 525-573.


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