Washington Legal Foundation

Critical Legal Issues

Working Paper Series No. 89

October 1998

ABOUT WLF'S LEGAL STUDIES DIVISION iii

ABOUT THE AUTHOR iv

INTRODUCTION 1

I. A BRIEF REVIEW OF DAUBERT 4

II. KUMHO TIRE CO., LTD. v. CARMICHAEL 5

III. DISTINGUISHING BETWEEN SCIENTIFIC AND

NON-SCIENTIFIC EXPERT TESTIMONY 8

IV. THE APPROPRIATE TEST FOR THE ADMISSIBILITY OF NON-

SCIENTIFIC EVIDENCE 14

A. KNOWLEDGE 18

B. ASSIST THE TRIER OF FACT 20

CONCLUSION 25

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David E. Bernstein is Associate Professor of Law at George Mason University School of Law.

This paper benefitted greatly from several discussions with Professors Harold Edgar and Bruce Kobayashi, from assistance with the philosophical issues by Mark Jankovic, from written comments by Mike Redmayne, and from the editorial assistance of Alisa Stein.

The views expressed here are those of the author and

do not necessarily reflect those of the Washington Legal Foundation.

"NON-SCIENTIFIC" EXPERTS:

WHAT DEGREE OF JUDICIAL

SCRUTINY SHOULD THEY FACE?

by

Professor David E. Bernstein

George Mason University School of Law

INTRODUCTION

On December 7, 1998, the U.S. Supreme Court will hear arguments in Kumho Tire Co., Ltd v. Carmichael.⁽¹⁾ The issue before the Court in Carmichael is the appropriate standard for the admissibility of non-scientific expert testimony. The Court's ruling will be one of the most important evidence decisions of the decade -- likely to have at least as dramatic an effect on the use of non-scientific expert testimony as the Supreme Court's landmark opinion five years ago in Daubert v. Merrell Dow Pharmaceuticals⁽²⁾ had on scientific testimony.

In Daubert, the Supreme Court established a strict reliability and relevance standard for the admissibility of expert scientific evidence.⁽³⁾ The Court declined to discuss whether and to what extent the decision applies to non-scientific expert testimony, and also declined to define the difference between scientific and non-scientific evidence.

Daubert, and the Court's elaboration on that ruling in last term's General Electric Co. v. Joiner,⁽⁴⁾ have significantly limited the admission of dubious "junk science" evidence -- proffered scientific evidence which ranges from poorly-supported speculation to outright fraud. However, much, perhaps most, misleading expert testimony is arguably non-scientific, and thus does not clearly fall within the scope of Daubert.

Since Daubert, some lower courts have argued that the ruling establishes the district courts as gatekeepers of expert testimony under Federal Rule of Evidence 702. Since 702 applies to all expert testimony, not just scientific testimony,⁽⁵⁾ these courts have held that Daubert implicitly requires courts to apply a strict reliability and relevance standard to the admissibility of non-scientific expert evidence. Other courts, however, have argued that Daubert is relevant only to scientific evidence, and that non-scientific expert testimony should be subjected to only minimal judicial scrutiny.

Meanwhile, Daubert's failure to discuss the demarcation between scientific and non-scientific expertise has led some courts to engage in refreshingly sophisticated discussions of the differences between scientific and non-scientific evidence. Other courts, by contrast, have used a crude "we know it when we see it" approach. The Supreme Court granted certiorari in Carmichael to resolve the lower courts' disputes as to how to distinguish science from non-science, and what standard should be applied to non-scientific expert testimony.

Because Daubert is so prominent in the debate over the admissibility of non-scientific evidence, this Working Paper begins with a brief review of that case. Part II reviews the facts of Carmichael, and the decisions of the lower courts in that case. Next, the Working paper discusses the appropriate distinction between scientific and non-scientific evidence. The author concludes that scientific expert evidence is based on theories and/or data that can be subjected to objective rational criticism, while non-scientific expert evidence is based on an expert's experience and/or training.

Finally, the Working Paper discusses the appropriate interpretation of Federal Rule of Evidence 702 in the context of non-scientific expert testimony. Rule 702 requires that such testimony be based on expert "knowledge" and be helpful to the jury. To meet the knowledge requirement, trial courts must ensure that a proffered non-scientific expert is either testifying from within a legitimate, recognized field of expertise, or is otherwise able to prove to the court that his testimony is based on true expertise. With regard to the helpfulness requirement, this paper argues that because non-scientific testimony is by definition not objectively refutable, attorneys will have strong incentives to hire venal experts or "outliers," those whose views are outside the mainstream. Adversarial non-scientific expert testimony is therefore unlikely to be helpful to the jury. The only way to ensure that non-scientific expert testimony represents mainstream expert opinion, and not the idiosyncratic results of expert-shopping by a party, is for courts to appoint their its own experts, either in place of, or in addition to, the parties' experts.

I. A BRIEF REVIEW OF DAUBERT

Daubert held that Federal Rule of Evidence 702 requires that district court judges serve as "gatekeepers," who exclude improper expert testimony.⁽⁶⁾ Parsing the language of Rule 702, the Court held that, to be admissible, proffered scientific evidence must constitute "scientific knowledge."⁽⁷⁾ This requirement, according to the Court, establishes a standard of evidentiary reliability. "Evidentiary reliability," the Court held, means "trustworthiness;" it depends on "scientific validity."⁽⁸⁾ The Court added that Rule 702 requires that proposed expert scientific testimony must "assist the trier of fact to understand the evidence or to determine a fact in issue."⁽⁹⁾ Proposed testimony must therefore have some scientific relevance to the issue at hand.⁽¹⁰⁾

The Court then enumerated four factors that may "bear on the inquiry" as to whether scientific evidence is admissible.⁽¹¹⁾ First, courts faced with challenged scientific evidence should determine whether the theory or technique at issue can be (or has been) tested. Peer review and publication, the Court added, are important, though not generally dispositive, factors. The Court also directed judges' attention to determining the known or potential rate of error of a technique in question, as well as to the existence and maintenance of standards controlling the technique's operation. A final consideration is the degree of the acceptance of the method or theory at issue.⁽¹²⁾

Chief Justice Rehnquist, joined by Justice Stevens, rejected the Court's dicta enumerating factors lower courts might consider in determining the admissibility of scientific evidence. Among other concerns, Rehnquist noted that it was unclear whether the four suggested factors "apply to an expert seeking to testify on the basis of 'technical or other specialized knowledge' -- the other types of expert knowledge to which Rule 702 applies," and, if not, what "is the difference between scientific knowledge and technical knowledge."⁽¹³⁾ Eventually, the Court would need to return to the issues raised by Rehnquist. It chose Carmichael as its vehicle to do so.

II. KUMHO TIRE CO., LTD. v. CARMICHAEL

The plaintiffs, members of the Carmichael family, were injured in a minivan accident when the right rear tire of the van failed and the van went out of control and overturned.⁽¹⁴⁾ Following the incident, the plaintiffs sued the manufacturer of the tire, Kumho Tire,⁽¹⁵⁾ in federal district court.

The Carmichaels hired George Edwards, an expert on tire failure, to examine the tire. Edwards concluded that a defect in the tire's design or manufacture caused the blowout. Before he could testify for the Carmichaels, Edwards became ill. He passed the case on to his employee, Dennis Carlson, who was also a credentialed expert on tire failure.

Carlson reviewed Edwards' file on the tire and discussed the case with Edwards. He then confirmed Edwards' conclusion that the tire was defective. Carlson did not examine the tire until after he had rendered his opinion on the cause of the blowout, but he claimed that the examination confirmed his earlier conclusion.

In his deposition, Carlson admitted that his physical analysis of the tire consisted solely of a visual inspection, but added that he had reviewed Edwards' report and conclusions, which were based on a more thorough inspection. Carlson claimed that the tire failed because of poor or insufficient adhesion between the rubber, steel, and nylon components of the tire. He did not find any affirmative evidence of a defect in the tire, but assumed that such a defect existed, because he failed to find any evidence of abuse of the tire by the vehicle's owners. Defense counsel had the following exchange with Carlson:

"Q. I guess then it all comes down to the subjective opinion of whoever is doing the tire failure analysis as to whether those factors of abuse you've listed . . . exist in a given tire?

A. Well, it's subjective if you have the knowledge and experience to analyze those factors."

Kumho Tire filed a motion asking the court to rule that Carlson may not testify at trial. Kumho did not challenge Carlson's qualifications, but instead argued that his testimony did not meet Daubert's standards. The court granted the motion after finding that "none of the four admissibility criteria outlined by the Daubert court are satisfied in this case."⁽¹⁶⁾ Because Carlson's testimony was the only evidence the Carmichaels could offer that the tire was defective, the court then granted summary judgment for Kumho Tire.

The Carmichaels appealed the district court's exclusion of Carlson's testimony to the U.S. Court of Appeals for the Eleventh Circuit. The Eleventh Circuit began its opinion by stating that Daubert applied solely to scientific expert testimony, and that the court therefore must determine how to distinguish between scientific and non-scientific expert testimony.⁽¹⁷⁾ Following the lead of several other federal courts,⁽¹⁸⁾ the Eleventh Circuit held that "a scientific expert is an expert who relies on the application of scientific principles, rather than on skill- or experience-based observation, for the basis of his opinion."⁽¹⁹⁾

Applying this standard, the court concluded that Carlson's testimony was non-scientific. Although "the laws of physics and chemistry are implicated in the failure of the Carmichaels' tire," Carlson claimed no scientific expertise, but based his opinion on his experience in analyzing failed tires.⁽²⁰⁾ Thus, the court concluded that Carlson's testimony fell outside the scope of Daubert, and that the district court erred in applying Daubert.⁽²¹⁾

The Court added, however, that even though the Daubert test does not apply to Carlson's testimony, under Rule 702 the district court must still determine if Carlson's testimony is sufficiently reliable and relevant to assist a jury.⁽²²⁾ The court noted that Carmichael presented "a number of potentially troubling criticisms of Carlson's alleged expertise and methodology, including his rendering of an opinion regarding the Carmichaels' tire before he had personally inspected its carcass."⁽²³⁾ The court gave no further guidance as to how the district court should review Carlson's testimony on remand.

III. DISTINGUISHING BETWEEN SCIENTIFIC AND NON-SCIENTIFIC EXPERT TESTIMONY

As noted previously, the Eleventh Circuit in Carmichael and several other federal courts have ruled that non-scientific expert evidence is based on experience and training, while scientific expert evidence is based on the application of objective scientific principles. This view has also received some support in the academic literature.⁽²⁴⁾ As discussed below, with slight modification, the Eleventh Circuit applied a sensible test for distinguishing between scientific and non-scientific testimony. By contrast, other judicial efforts to differentiate between scientific and non-scientific expert evidence have lacked coherence.⁽²⁵⁾

As the Eleventh Circuit noted in Carmichael, the Sixth Circuit wrote a particularly well-reasoned explanation of the distinction between scientific and non-scientific evidence in Berry v. City of Detroit.⁽²⁶⁾ Berry distinguished between scientific and non-scientific evidence with an illustration. Suppose, said the court, a party to a case wanted to explain to a jury how a bumblebee is able to fly. The party could call an aeronautical engineer to testify. The engineer would base his testimony on universal scientific principles of flight, which he would apply to the bumblebee. This testimony would thus be scientific.⁽²⁷⁾

On the other hand, if the party wanted to prove to the jury that bumblebees always take off into the wind, the party could call a beekeeper to testify, even if that beekeeper had no scientific training. If the beekeeper had sufficient experience in watching bees, he could testify regarding the flight patterns of bees based on that experience.⁽²⁸⁾ The court noted that "[t]he foundation would not relate to his formal training, but to his firsthand observations. In other words, the beekeeper does not know any more about flight principles than the jurors, but he has seen a lot more bumblebees than they have."⁽²⁹⁾

Carmichael adopted Berry's analysis, and added an analogy of its own. The court gave the example of an auto mechanic testifying about whether a spark plug burnt out because of normal wear or because of a defect. An experienced mechanic, argued the court, may recognize patterns of normal and abnormal wear on an auto part "even though he has no knowledge of the general principles of physics or chemistry that might explain why or how a spark plug works."⁽³⁰⁾ This expert's testimony would be non-scientific, while the testimony of another expert on the nature and effects of combustion on spark plugs would be scientific.

The conclusions of Berry, Carmichael, and like-minded cases are consistent with at least one of the most important schools of philosophy of science -- that founded by Sir Karl Popper.⁽³¹⁾ Popper introduced falsifiability as the demarcation criterion between science and non-science in The Logic of Scientific Discovery.⁽³²⁾ A theory is falsifiable if one can imagine an observation that would show the theory false. According to Popper, only falsifiable theories are scientific.

Over the years, Popper's "falsificationism," suffered withering criticism, including ultimately by Popper himself.⁽³³⁾ Building on the work of Popper, William Hartley advanced a more useful view of demarcation. According to Hartley, the demarcation should be between critical and non-critical theories. For a theory to qualify as scientific it must be open to criticism.⁽³⁴⁾ Thus, Hartley would exclude from science theories that have "built in devices for avoiding or deflecting critical arguments empirical or otherwise."⁽³⁵⁾ This position was accepted by Popper himself as a reasonable generalization of his later views.

Courts are not in the business of endorsing philosophical positions, but one need not accept Popperian epistemological theory to see the usefulness of the Popperians' conclusion on the demarcation issue for interpreting Rule 702. Rule 702 requires courts to distinguish between scientific knowledge and other forms of expertise, and the rule operates in a system where cross-examination is relied upon to get to truth. The Popperian philosophical view can quite easily be translated into a practical, sound legal standard for distinguishing between scientific and non-scientific expert testimony: for expert testimony to be considered scientific, it must be vulnerable to logical criticism and questioning on cross-examination.⁽³⁶⁾

Expert testimony based on training and experience does not have this vulnerability, because it ultimately relies on an argument from authority, not reason. Let us imagine, for example, a cross-examination of the hypothetical auto mechanic discussed in the Eleventh Circuit's opinion in Carmichael:

Q. What is the basis for your opinion that the spark plug failed because of a defect?

A. My twenty years of experience as an auto mechanic.

Q. How many failed spark plugs have you seen?

A. At least one thousand.

Q. How do you know what the cause of failure is?

A. Mister, I've been looking at spark plugs for twenty years. I know how to tell a good spark plug from a defective one.⁽³⁷⁾

One can imagine a similar cross-examination of Berry's beekeeper. At the point that an expert relies on the authority of his training and experience, his testimony is no longer criticizable in the Popperian sense, just as a religious person's views are no longer criticizable once he has appealed to faith.⁽³⁸⁾

Thus, the test endorsed by Berry, Carmichael, and Starzecpyzl essentially comports with the Popperian view of the demarcation issue -- evidence based on training and experience cannot be "scientific" because it is not vulnerable to criticism. Note that applying Popperian principles, the word "scientific" as used in Rule 702 should be considered a legal term of art, meaning "based on objective, criticizable principles." Incorporating this reasoning into Carmichael's enunciation of the distinction between scientific and non-scientific evidence, that case should be read as holding that "a scientific expert is an expert who relies on the application of [objective, criticizable] principles, rather than on skill- or experience-based observation, for the basis of his opinion."

This modified Carmichael test for distinguishing scientific from non-scientific expertise will not always correlate with the impressionistic distinctions between science and non-science often relied upon by judges. For example, testimony by a doctor based on his experience that a particular broken arm will take eighteen months to heal completely is non-scientific testimony; on the other hand, testimony by an economist in an antitrust case that the establishment of a monopoly will lead to higher consumer prices would be scientific testimony, because it is based on objective, criticizable principles.⁽³⁹⁾

IV. THE APPROPRIATE TEST FOR THE ADMISSIBILITY OF NON-SCIENTIFIC EVIDENCE

Once the Supreme Court determines the appropriate standard for distinguishing between scientific and non-scientific expert testimony, it must determine the appropriate standard for the admissibility of non-scientific testimony. In order to properly resolve this issue, one must first ascertain why there are special rules for the admissibility of expert witness testimony that do not apply to other testimony.

The most significant distinction between ordinary fact witnesses and expert witnesses is that there is typically a very limited pool of the former, and an almost unlimited pool of the latter. For example, there is a limited pool of eyewitnesses to any particular event. By contrast, there is, for example, a virtually unlimited pool of qualified experts who could testify in a typical medical malpractice case. While attorneys are stuck with the testimonial limitations of the available fact witnesses, an attorney who needs an expert has a virtually unlimited opportunity to "shop" for an expert with a pleasing courtroom manner who will testify that he or she agrees with the attorney's theory of the case.⁽⁴⁰⁾ Some of these potential expert witnesses will be venal hired guns who will say anything for money. As Judge Jack Weinstein has noted, "[a]n expert can be found to testify to the truth of almost any factual theory, no matter how frivolous."⁽⁴¹⁾

Ordinary fact witnesses may also have their biases, but attorneys can only take advantage of these biases if the witnesses already exist; attorneys cannot normally shop for an ordinary fact witness. By contrast, attorneys can seek expert witnesses who will parrot the attorneys' line, and, indeed, implicitly "bribe" them to do so.⁽⁴²⁾

Moreover, ordinary biases, such as a familial or friendly relationship to one of the parties, can typically be brought out on cross-examination.⁽⁴³⁾ Some authorities have argued that cross-examination will also reveal an expert witness' bias to the jury.⁽⁴⁴⁾ This is dubious, because it not at all clear how opposing counsel can discredit a hired gun expert for taking money for his testimony, given that opposing counsel will have his own expert -- who may be scrupulously honest -- on his payroll.

In any event, even if the biases of hired guns can be revealed through cross-examination, that does not resolve the problems caused by expert-shopping. Not all, and perhaps not even most, experts who testify to opinions outside the mainstream of their field are venal hired guns.

Daubert attempted to alleviate the problem of venal and "outlier" scientific experts by requiring a detailed preliminary inquiry into the reliability of proffered scientific testimony. The Daubert test, however, simply cannot be strictly applied to non-scientific testimony as defined in this paper. Because non-scientific testimony is based on subjective training and experience, non-scientific evidence will never meet the four Daubert criteria: by definition, it will not be testable, cannot be peer reviewed or published, is unlikely to have a known rate of error, and cannot be proven to be "generally accepted."⁽⁴⁵⁾ To apply the four Daubert factors to non-scientific expert testimony would mean excluding all non-scientific expert testimony.

Such a result was clearly not intended by the Daubert Court, nor would it be wise. A great deal of non-scientific specialized expert knowledge exists that could be helpful to jurors in a wide range of cases. Think, for example, of appraisers of unique fine art, or of historians, musicians, businessmen, and experts on the modus operandi of criminal enterprises; all of these experts have specialized knowledge based on training and experience, and all have a role to play in appropriate cases.

While non-scientific evidence should not be universally excluded, some courts have gone too far in the opposite direction. These courts have concluded that because the Daubert criteria cannot be applied to non-scientific expert testimony, all such testimony should be admitted as long as the expert has appropriate qualifications.⁽⁴⁶⁾ Yet these rulings are contrary to the clear implications of Daubert and Rule 702.

As discussed previously, Daubert held that district courts have solemn gatekeeping responsibilities under Rule 702. If anything, the district court's gatekeeping role is more important for non-scientific expert testimony than for scientific testimony. Because non-scientific expert testimony is not criticizable in a philosophical sense, it will often be far more difficult for the opposing side to discredit a mistaken or idiosyncratic non-scientific opinion than a mistaken or idiosyncratic scientific opinion.⁽⁴⁷⁾

Rule 702 explicitly establishes the applicable standard for the admissibility of non-scientific expert evidence. The rule requires that non-scientific experts testify only to "technical or other specialized knowledge" that will assist the jury. The "knowledge" and the "assist the jury" criterion will be considered below in turn.

A. Knowledge

In order to ensure that an expert is testifying to non-scientific "knowledge," a court should ensure that the expert can in fact do what he claims to be able to do. Such ability can be presumed when the expert is (1) properly trained and has appropriate experience in a recognized field of expertise that has nonjudicial uses,⁽⁴⁸⁾ and (2) he is testifying within the scope of his expertise.

Several American jurisdictions have already adopted the "field of expertise" test for the admissibility of non-scientific expert evidence.⁽⁴⁹⁾ Under this test, testimony is admitted where the expert has proven his knowledge and experience in the area in question and "where the subject matter of the opinion forms part of a body of knowledge or experience which is sufficiently organized or recognized to be accepted as a reliable body of knowledge or experience."⁽⁵⁰⁾ Thus, courts should presume that an experienced appraiser of Ming Dynasty Chinese art who has consulted for renowned art museums and auction houses is capable of valuing a Ming vase. Astrologers, psychics, and other charlatans who manage to make a living from their deceit should not be admitted.⁽⁵¹⁾ Once testimony passes the field of expertise test, the court should ensure that the expert is being as careful as he would be in his regular professional work outside his paid litigation consulting.⁽⁵²⁾

In cases where no recognized non-forensic field of expertise exists, courts should test the expert to see whether his claimed expertise is real. Before Daubert, courts did not diligently perform this task. For example, in United States v. Johnson,⁽⁵³⁾ an Evidence casebook standard, the conviction of the defendants for importing marijuana hinged on the expert testimony of one of their former co-conspirators that the marijuana in question was grown in Columbia, not the United States. This "expert" had no direct knowledge of whether the marijuana was imported or domestic, but claimed that as a longtime marijuana dealer and smoker, he was able to distinguish not only between Columbian-seed and American-seed marijuana, but between Columbian-seed marijuana grown in the United States, and Columbian-seed marijuana grown in Columbia. Incredibly, despite expert testimony by the defendants' expert botanist that the expert's claimed skill was impossible, the court allowed the witness to testify, and the jury found the defendants guilty beyond a reasonable doubt.

Perhaps the expert witness in Johnson really could do what he claimed. If so, the district court, on objection from the defendants' attorney, should have forced the government to prove it. A voir dire should have been held during which the expert witness would have been required to correctly distinguish among different varieties of marijuana, grown in different locations. Similarly, in Carmichael, if on remand the district court finds that Carlson, the Carmichaels' expert, was not testifying within a recognized non-forensic field of expertise, the Carmichaels should be forced to prove that Carlson can distinguish between a tire blown as a result of a defect, and a tire blown from other causes.⁽⁵⁴⁾

A potential objection to requiring such voir dires is that they would be too burdensome to the party seeking to present an expert. It must be remembered, however, that the presentation of expert testimony is an exception to the general rule barring testimony by witnesses who have no direct knowledge of the facts, and that the burden is always on the proffering party to prove that his expert's testimony should be admitted.

B. Assist the Trier of Fact

Even if a non-scientific expert is testifying based on his knowledge, he will not necessarily be assisting the trier of fact. Indeed, as argued below, in order to meet Rule 702's requirement of assistance to the jury, non-scientific experts should only be allowed to testify as neutral, court-appointed experts. At the very least, if a court feels obligated to allow adversarial experts, it should also appoint its own expert or experts.

Learned Hand summed up the problem with experts almost one hundred years ago: "[H]ow can the jury judge between two statements each founded upon an experience confessedly foreign in kind to their own? It is just because [jurors] are incompetent for such a task that the expert is necessary at all."⁽⁵⁵⁾ According to Hand, testimony from competing experts is not helpful to the jury: "One thing is certain, [the jury] will do no better with the so-called testimony of experts than without, except where it is unanimous. If the jury must decide between such they are as badly off as if they had none to help."⁽⁵⁶⁾

In the context of scientific evidence, Daubert responds, albeit imperfectly, to Hand's concerns. Daubert ensures both that expert scientific testimony will be based on mainstream principles, and that there will be objective standards by which to judge the testimony. Juries may not understand epidemiology, for example, but they can understand mathematical errors, data dredging, high error rates, and other sins that are likely to be revealed during cross-examination of a dubious epidemiology expert who managed to barely pass the Daubert test.

By contrast, juries have no objective way of judging the testimony of the average non-scientific expert witness. Our system assumes, perhaps optimistically, that the jury can determine if the expert is outright lying. But beyond that, what if the expert is simply shading the truth? Or, what if the expert is simply an eccentric or outside the mainstream?

Indeed, parties have every incentive to hire "outliers." Consider the case of A vs. B, where the issue is the value of a unique Ming vase that was destroyed in a fire. Pictures and descriptions of the vase still exist. There are one thousand Ming Dynasty art experts in the world. Each side, after surveying a dozen experts each, concludes that the median expert believes that the vase was a 15^th Century vase worth approximately $250,000, with most experts clustering at the $200,000 to $300,000 range. However, due to normal bell curve distributions, upon further inquiry "A" is able to find credible experts who believe the vase was a 14^th Century vase worth between $500,000 and $700,000, while "B" retains experts who believe that the vase was an early 17^th Century vase worth less than $75,000.

The outside-the-mainstream experts, not their respectable counterparts, will appear in court. Neither side has an incentive to hire a mainstream expert.⁽⁵⁷⁾ The experts the attorneys do hire are sincere, if outside the mainstream, so even a particularly perceptive jury will not be able to discern any dishonesty. There is no objective way of valuing the art, short of auction, which in this case is impossible, so neither side's experts will likely be discredited. The attorneys will naturally conclude that the jury, left with no other device for decision, will attempt to more or less split the difference between the two sides' experts. So instead of retaining experts whose views best represent those of the experts' colleagues, the parties are likely to hire experts on either extreme.

This type of scenario, with each side hiring experts with polarized positions, presents itself frequently in situations involving non-scientific evidence, ranging from appraisals, to testimony by psychiatrists in child custody hearings, to testimony, as in Carmichael, about the cause of a tire's failure. In such cases, introducing adversarial expert testimony leaves the trier of fact with a choice "between two opinions, both equally credentialed, but lacking any factual underpinning."⁽⁵⁸⁾ Instead of the testimony being helpful to the jury, it will in fact be misleading -- worse than useless. The radical conclusion one must come to is that if a court decides to admit non-scientific testimony, Rule 702 dictates that adversarial expert testimony be excluded as not helpful to the trier of fact.⁽⁵⁹⁾

In some cases, excluding adversarial expert non-scientific testimony might not seem to present much of a problem, because courts can admit scientific evidence as a substitute for non-scientific evidence. Thus, for example, courts could admit a botanist to identify the origins of seized marijuana instead of a marijuana dealer.

Yet substituting science for non-science presents problems of its own. First, in some cases a non-scientific expert may have more reliable knowledge than the competing "scientist." A wine expert, for example, may very well be better able to identify the vineyard that a wine came from than a botanist. A second problem is that non-scientific experts are likely to frequently be both less expensive and more readily available than scientific experts, and one hesitates to place extra burdens on litigants, particularly when people contentedly rely on non-scientific expertise in non-legal contexts.⁽⁶⁰⁾

Putting such problems aside, scientific expertise will not always be available, as in the Ming vase example noted above. Yet expert testimony is needed in such situations, as juries are not competent on their own to, for example, determine the value of a Ming vase.

The solution is for courts to exercise their authority under Federal Rule of Evidence 706 to appoint experts. Court-appointed experts, it is true, could potentially be outside the mainstream, but this is much less likely to occur when the experts are appointed by the court than when they are hired by the parties, who, as explained above, are often intentionally seeking "outliers."⁽⁶¹⁾

Ideally, a panel of court-appointed experts would be the only experts permitted to testify. This idea seems to go so far against the traditions of our adversarial system, however, that it is unlikely to be accepted. A second-best solution would be for the court to appoint its own experts in addition to the adversarial experts testifying for the parties. This system would not only give the jury an unbiased, mainstream perspective, but would also give the parties an incentive to hire experts closer to the mainstream than they otherwise would. After all, if either party's experts' views diverged too far from the courts' experts, the jury would reasonably become suspicious that the deviant experts were biased in favor of their employers.

This paper defines non-scientific expert testimony as testimony based on the expert's training and experience. In the past, such testimony received little scrutiny from courts. Yet non-scientific expert evidence can be at least as confusing and misleading as scientific evidence, and Federal Rule of Evidence 702 does not differentiate between scientific and non-scientific evidence in mandating that the district court act as a gatekeeper that excludes proffered expert evidence when that evidence either does not constitute "knowledge" or will not be helpful to the jury.

To allow trial courts to properly fulfill their gatekeeping function, the Supreme Court should rule in Carmichael that non-scientific expert testimony is only admissible if the expert has proven that his expertise is genuine. The expert could prove this either by showing that his expertise comes within a legitimate field of expertise, or by otherwise demonstrating his expertise to the judge.

Also, because non-scientific expertise cannot be objectively criticized, the only way to ensure that the experts' testimony is actually helpful to the jury is to curtail the parties' reliance on experts whose views conflict with mainstream expert opinion. The Court should therefore strongly encourage district courts to appoint non-scientific experts, either instead of or in addition to the parties' experts.

1. Cert. granted, June 22, 1998.

2. Daubert v. Merrell Dow Pharms., Inc., 509 U.S. 579 (1993).

3. See generally David E. Bernstein, The Admissibility of Scientific Evidence after Daubert v. Merrell Dow Pharmaceuticals, 15 Cardozo L. Rev. 2139 (1994); David E. Bernstein & Robert P. Charrow, Scientific Evidence in the Courtroom: Admissibility and Statistical Significance After Daubert (Washington Legal Foundation 1993).

4. 118 S. Ct. 512 (1997).

5. Rule 702 states: "If scientific, technical, or other specialized knowledge will assist the trier of fact to understand the evidence or to determine a fact in issue, a witness qualified as an expert by knowledge, skill, experience, training, or education, may testify thereto in the form of an opinion or otherwise."

6. Daubert, 509 U.S. at 597.

7. Id. at 590 n.9.

8. Id.

9. Id. at 591.

10. Id.

11. Id. at 593-94.

12. Id.

13. Id. at 599 (Rehnquist, C.J., concurring).

14. The basic facts are taken from Carmichael v. Samyang Tires, Inc., 923 F. Supp. 1514 (S.D. Ala.1996); and Carmichael v. Samyang Tire, Inc., 131 F.3d 1433 (11th Cir. 1997).

15. The original named defendant, Samyang Tire, merged into Kumho Tire in 1984 and was not an independent corporate entity at the time of the accident.

16. 923 F. Supp. at 1521.

17. 131 F.3d at 1436.

18. Berry v. City of Detroit, 25 F.3d 1342 (6th Cir. 1994); accord Sorenson v. Robert B. Miller & Assoc., Inc., 1996 WL 515351 (6th Cir.); Compton v. Subaru of America, Inc., 1996 WL 210407 (10th Cir. 1996); United States v. Starzecpyzl, 880 F. Supp. 1027 (S.D.N.Y. 1995) (holding that forensic document examination is not scientific, even though both parties argued that it is); see also Gentry v. Mangum, 466 S.E.2d 171 (W. Va. 1995) (expert testimony on police practices not scientific because expert does not rely on "any 'scientific knowledge' or 'methodology,' but upon a range of factors including his experiences and understanding of police work").

19. 131 F.3d at 1435.

20. Id. at 1436.

21. Id.

22. Id.

23. Id.

24. Edward Imwinkelried, The Next Step After Daubert: Developing a Similarly Epistemological Approach to Ensuring the Reliability of Nonscientific Expert Testimony,15 Cardozo L. Rev. 2271, 2291 (1994); see also David E. Bernstein, The Science of Forensic Psychiatry and Psychology, 2 Psychology, Psychiatry & L. 75 (1995), available at http://members.aol.com/deliotb/psych.html.

25. E.g., Officer v. Teledyne Republic/Sprague, 870 F. Supp. 408, 410 (D. Mass. 1994) (distinguishing "controversial and novel scientific hypotheses," to which Daubert applies, from "fields like design engineering where 'general acceptance' is the norm, not the exception"); Lappe v. American Honda Motor Company, Inc., 857 F. Supp. 222, 228 (N.D.N.Y. 1994) (distinguishing scientific testimony from an engineer's testimony based "on facts, an investigation, and traditional technical/mechanical expertise"), aff'd, 1996 WL 170209 (2d Cir. 1996).

Some scholars have attempted to distinguish between "hard" and "soft" scientific evidence, particularly in the context of mental health evidence. Charles Bleil, Evidence of Syndromes: No Need for a "Better Mousetrap,'" 32 S. Tex. L. Rev. 37, 67-69 (1990); Cathleen C. Herasimchuk, A Practical Guide to the Admissibility of Novel Expert Evidence in Criminal Trials Under Federal Rule 702, 22 St. Mary's L.J. 181, 205, 216-17 (1990); David McCord, "Syndromes, Profiles & Other Mental Exotica: A New Approach to the Admissibility of Nontraditional Psychological Evidence in Criminal Cases, 66 Ore. L. Rev.19, 35, 38-41 (1987). According to this line of reasoning, hard scientific evidence is based on objective testing and the traditional standards of scientific verification and falsifiability. "Soft" scientific evidence, in contrast, is an opinion based on the professional's education, training, and experience, and is therefore not verifiable or falsifiable. These scholars failed to adequately explain what makes so-called "soft" scientific evidence scientific at all. A better view is that so-called "soft" scientific expert evidence is actually non-scientific evidence.

26. 25 F.3d 1342 (6th Cir. 1994).

27. Id. at 1350.

28. Id.

29. Id.; accord United States v. Jones, 107 F.3d 1147, 1158 (6th Cir. 1997).

30. 131 F.3d at 1436 n.6.

31. The primary opposing school of philosophy of science views science as a sociological phenomena. This school of philosophy of science is of limited use to judges trying to sort science from non-science.

32. Karl Popper, The Logic of Scientific Discovery (1934).

33. See Karl Popper, Replies to My Critics 983 (1974); see generally Kenneth R. Foster & Peter W. Huber, Judging Science 47-48 (1997).

34. William Bartley, The Retreat of Commitment 206 (1962).

35. William Bartley, Critical Study: The Philosophy of Karl Popper Part III: Rationality, Criticism, and Logic, 11 Philosphia 196 (1982).

36. Other schools of epistemology hold that there is no real difference between types of knowledge. Arguably, one can model testimony that appears to be non-critical testimony into criticizable testimony by investigating the ultimate underlying scientific basis of how the expert reached his conclusions, even when the expert purports to be relying on training and experience. Even testimony based on the senses, such as eyewitness testimony, has an underlying scientific basis. The point here, however, is even if such modeling can be done in theory -- for example, through computer-generated artificial intelligence models -- it cannot be done in a sufficiently time and cost-effective manner, nor a manner that will likely be explicable to lay jurors, to make it useful for legal purposes. In courtroom practice, then, if perhaps not in epistemological theory, expert testimony based on experience and training will be non-criticizable.

37. This type of response by the mechanic is what the court had in mind when it used the mechanic as an example of a non-scientific expert. Several readers of this paper have suggested that the mechanic's response is unrealistic, because the expert would explain his rationale in more detail. In fact, however, argument from authority by experts seems to be rather common. Carlson appears to have made such an argument in Carmichael, and other types of experts are prone to it as well. For example, in one case, a prosecutor asked a psychiatrist why the psychiatrist believed that a defendant suffered from an abnormality of mind when the defendant committed a killing. The psychiatrist responded: "On the reason of my diagnosis and my assessment and my experience of 32 years. That is enough reason, I suggest." Malcolm Brown & Paul Wilson, Justice and Nightmares 155 (1992).

If the mechanic did in fact explain how he distinguishes a defective sparkplug from a non-defective one, his theory would be subject to criticism, and his testimony would be scientific as that word is defined in this paper.

38. That does not mean that the expert or the religious person is necessarily mistaken. It simply means that their position is not "criticizable."

39. As Professor David Faigman argues, social science evidence should not be treated any differently for evidentiary purposes than evidence from fields traditionally considered "scientific." David L. Faigman, To Have and Have Not: Assessing the Value of Social Science to the Law As Science and Policy, 38 Emory L.J. 1005, 1009 (1989).

40. Samuel R. Gross, Expert Evidence, 1991 Wisc. L. Rev. 1113, 1127.

41. Jack B. Weinstein, Improving Expert Testimony, 20 U. Rich. L. Rev. 473, 482 (1986).

42. Gross, supra note 41.

43. Id.

44. Ronald J. Allen & Joseph S. Miller, The Common Law Theory of Experts: Deference or Education?, 87 Nw. U. L. Rev. 1131, 1146 (1993).

45. Cf. James T. Richardson et. al, The Problems of Applying Daubert to Psychological Syndrome Evidence, 79 Judicature 10, 11 (1995) ("[T]he nature of certain social and behavioral science theories may be inherently inconsistent with Daubert criteria such as 'falsifiability' and 'error rates.'").

46. E.g., Iacobelli Construction, Inc. v. County of Monroe, 32 F.3d 19 (2d Cir. 1994); In Re: Orthopedic Bone Screw Products Liability Litigation, 1997 WL 39583 (E.D. Pa.); Thornton v. Caterpillar, Inc., 951 F. Supp. 575 (D.S.C. 1997); see also Imwinkelried, supra note 24, at 2290-2293; Linda S. Simard & William G. Young, Daubert's Gatekeeper: The Role of the District Judge in Admitting Expert Testimony, 68 Tulane L. Rev. 1457 (1994).

47. Cf. Watkins v. Telsmith, Inc., 121 F.3d 984, 991 (5th Cir. 1997) ( "[I]t seems exactly backwards that experts who purport to rely on general engineering principles and practical experience might escape screening by the district court simply by stating that their conclusions were not reached by any particular method or technique." ).

48. Cf. Daubert v. Merrell Dow Pharmaceuticals, 43 F.3d 1311,1317 (9th Cir. 1995) (suggesting that an important criterion for the admissibility of expert evidence is the non-forensic use of the expertise by the expert).

49. E.g., Van Blargan v. Williams Hospitality Corp., 754 F. Supp. 246, 248 (D.P.R. 1991) (suggesting that only members of recognized professions bound by ethical codes which will "insure . . . objective testimony and the truth as seen by the professional" should be allowed to testify as non-scientific experts). For other cases, see Michael H. Graham, Handbook of Federal Evidence sec. 702.4, at 629, 632 (3d ed. 1991).

50. Regina v. Bonython, 15 Aust. Crim. Rep. 364, 366 (1984). This is an Australian case. Australian courts have been applying the field of expertise test to expert evidence for years.

51. Unfortunately, in the past many courts have allowed experts to testify just because

their testimony had been accepted by other courts, without engaging in an independent evaluation of whether the expert was testifying within a proper field of expertise. See Mark Hansen, Believe It or Not, ABA J., June 1993, at 64 (discussing a discredited footprint expert whose testimony had supported many convictions).

52. See Advisory Committee Note to Proposed Amendment to Rule 702 (currently pending); Sheehan v. Daily Racing Form, Inc., 104 F.3d 940, 942 (7th Cir. 1997); Braun v. Lorillard Inc., 84 F.3d 230, 234 (7th Cir. 1996).

53. 575 F.2d 1347 (5th Cir. 1978).

54. This assumes that Carlson's testimony is in fact non-scientific testimony as defined in this article. Having not seen the full transcript of his testimony, the author cannot say for sure that this is the case.

55. Learned Hand, Historical and Practical Considerations Regarding Expert Testimony, 15 Harv. L. Rev. 40, 54 (1902).

56. Id. at 56.

57. Note that there is no ethical obligation on attorneys to hire mainstream experts. Indeed, their ethical duty to zealously advocate for their clients may require them to hire outliers if it would help their client's case.  See David Bernstein, Note, Out of the Frye-ing Pan and Into the Fire: The Expert Witness Problem in Toxic Tort Litigation, 10 Rev. Litig. 117, 159 (1990).

58. Rotman v. National R.R. Passenger Corp., No. 9200373B (Mass. Super.), quoted in Massachusetts Lawyers Weekly, Jan. 31, 1994, at 27.

59. Cf. id.

60. For example, consider the doctor who testifies that based on his experience the plaintiff's broken arm will take eighteen months to heal. One could instead require the plaintiff to find a "scientific" expert who will look at hundreds of X-rays of broken arms, find out how long it took each to heal, and then compare those X-rays with the X-ray of the broken arm in question. No patient would require this needless expenditure of resources before relying on the doctor's opinion, and neither should the court.

61. Moreover, judges could seek to get the parties to agree on a list of acceptable experts.