Christophersen v. Allied-Signal Corp.
939 F.2d 1106 (5th Cir. 1991) (en banc)

PER CURIAM: The issue presented by this appeal is how a court should determine the admissibility of expert opinion testimony. At the summary judgment stage of this case, plaintiff attempted to establish medical causation of a toxic tort through the testimony of a single expert witness. The district court held that the basis of the expert's opinion was insufficiently reliable and, in the alternative, that the expert's testimony would have been more prejudicial than probative. With the expert's testimony ruled inadmissible, plaintiff was left without proof of causation. The district court entered summary judgment for the defendants. We affirm.

Christophersen died in March of 1986 as a result of a rare, small- cell form of cancer that originated in his colon and metastasized to his liver. During the fourteen years preceding his death, Christophersen worked for Marathon at its plant in Waco, Texas. At that plant, Marathon produces nickel/cadmium batteries. Christophersen never was directly involved in the production of these batteries. The record, however, indicates that over a number of years Christophersen's job duties required him to visit the area of the plant in which the batteries were manufactured. During these visits, Christophersen was allegedly exposed to fumes resulting from the manufacturing process. Plaintiffs, Christophersen's surviving spouse and child, contend that these fumes contained particles of nickel and cadmium and that Christophersen's exposure to these heavy metals caused the cancer that resulted in his death....

The district court ... granted Marathon's motion for summary judgment because the plaintiffs did not present sufficient evidence of causation. In reaching this conclusion, the court focused on the affidavit of the plaintiffs' expert witness, Dr. Miller, who concluded that Christophersen's exposure to nickel and cadmium at Marathon caused the cancer that resulted in his death. The district court undertook an in-depth review of the basis for Dr. Miller's conclusion and determined that his opinion should be excluded. On appeal, a panel of this court reversed, holding that Dr. Miller's opinion was not so fundamentally unreliable that the jury should not consider it. Defendants timely petitioned this court for rehearing en banc....

The Federal Rules of Evidence, combined with Frye v. United States, 293 F. 1013 (D.C. Cir. 1923), provide a framework for trial judges struggling with proffered expert testimony. The signals are not neatly cabined categories, and we disentangle them only to accent the independent significance of each. (1) Whether the witness is qualified to express an expert opinion, Fed. R. Evid. 702; (2) whether the facts upon which the expert relies are the same type as are relied upon by other experts in the field, Fed. R. Evid. 703; (3) whether in reaching his conclusion the expert used a well-founded methodology, Frye; and (4) assuming the expert's testimony has passed Rules 702 and 703, and the Frye test, whether under Fed. R. Evid. 403 the testimony's potential for unfair prejudice substantially outweighs its probative value. These four signals or inquiries introduce no new concepts to our jurisprudence. They are only guideposts drawn from the Federal Rules of Evidence and our cases. We list these inquiries, but in doing so we do not intend that they be applied mechanically. At the same time, they often will naturally lend themselves to sequential application. The reality is that trials are too varied for fixed molds; we construct none today.

The first three steps are best understood as threshold requirements that all expert testimony must meet before being deemed admissible.... Rule 403, on the other hand, provides an overlay--a final mechanism for screening out otherwise admissible testimony whose potential for prejudice substantially outweighs its probative value. Cf. 22 C. Wright & K. Graham, Federal Practice & Procedure, 5213 at 258-59 (1978).

The first question concerns the expert's qualifications: Is the witness--because of his specialized knowledge, skill, experience, training, or education in the relevant field--qualified to express an expert opinion on the topic at issue? Fed. R. Evid. 702. The Advisory Committee Note accompanying Rule 702 reads the broad language of the rule to permit expert testimony not only by experts carrying formal credentials such as university degrees and professional memberships but also by so-called skilled witnesses, whose experiences permit them to testify with authority on a given topic. The areas of inquiry that expert testimony may address are similarly broad, including scientific and technical questions as well as any other area of specialized knowledge. An expert may testify in his area of expertise "in the form of an opinion or otherwise." This much is rote. The more subtle problem, and our caveat, is that the inquiry into the qualifications of an expert should not be a substitute for scrutinizing an expert's reasoning or methodology. At this stage, the only question for the trial court is whether the expert is generally qualified to render an opinion on the question in issue.

Second, if the expert is qualified, are the facts and data that serve as a basis for the expert's opinion the same type of facts as other experts in the same field reasonably rely upon in forming their opinions? Fed. R. Evid. 703. While testimony based on the personal observations of the expert is preferable, neither the rules nor our cases have insisted on personal examinations. The reports and statements of others such as doctors, nurses, or medical personnel, while not as valuable as testimony based on the expert's own observations, can provide a reliable basis for the expert's opinion, at least when reliance on such sources is the custom of the discipline. At the same time, a common-sense skepticism may be warranted when an expert's factual basis is derived, not from treatment or observation, but from subjective information obtained from counsel or client in preparation for trial. But such skepticism should not necessarily lead us to exclude the expert's opinion. So long as the facts upon which the expert bases his opinion are those "perceived or made known to the expert at or before the hearing" and are "of a type reasonably relied upon by experts in the particular field," we should proceed to evaluate the expert's methodology. Fed. R. Evid. 703.

The third factor is the Frye test. We ask whether in reaching his conclusion, the witness used a well-founded methodology or mode of reasoning, one "sufficiently established to have gained general acceptance in the particular field in which it belongs." Frye, 293 F. at 1014; see also Osburn v. Anchor Laboratories, Inc., 825 F.2d 908 (5th Cir. 1987), cert. denied, 485 U.S. 1009, 108 S. Ct. 1476, 99 L. Ed. 2d 705 (1988). As long as the expert's methodology is well founded, the nature of the expert's conclusion is generally irrelevant, even if it is controversial or unique. See Peteet v. Dow Chemical Co., 868 F.2d 1428, 1433 (5th Cir. 1989); Osburn, 825 F.2d at 915. In fact, in Osburn the plaintiff's and the defendant's experts relied on essentially the same diagnostic methodologies but drew opposite conclusions from the available information. We did not attempt to determine which expert's conclusion was more in line with the consensus in the scientific community. Instead we stated, "a jury must be allowed to make credibility determinations and weigh the conflicting evidence in order to decide the likely truth of a matter not itself initially resolvable by common knowledge or lay reasoning." Id. at 916. "An expert's opinion need not be generally accepted in the scientific community before it can be sufficiently reliable and probative in support of a jury finding." Osburn, 825 F.2d at 915.

Finally, Rule 403 serves a general screening function for otherwise admissible evidence. Assuming the witness's testimony is relevant and the witness is qualified, and assuming his testimony has the appropriate factual basis and his methodology is well founded, the only remaining inquiry is the balancing authorized in Rule 403: "Although relevant, evidence may be excluded if its probative value is substantially outweighed by the danger of unfair prejudice, confusion of the issues, or misleading the jury, or by considerations of undue delay, waste of time, or needless presentation of cumulative evidence." In the 403 balancing inquiry, courts may consider issues that were appropriately excluded from the three preceding threshold inquiries, which are narrower in scope. If, taking all considerations into account, a court finds that the potential for prejudice substantially outweighs the probative value, the court may opt to exclude the testimony. Unlike Rules 702 and 703, which define admissibility thresholds for expert-opinion evidence, Rule 403 "creates a power to exclude otherwise admissible evidence; it gives no discretion to admit evidence that is subject to exclusion under some other rule." 22 C. Wright & K. Graham, Federal Practice & Procedure, 5213 at 258-59 (1978). We caution, however, that clearing the hurdles of Article VII of the Federal Rules of Evidence will not alone ensure approval under Rule 403. An application of these principles to this case follows.


Although the district court did not conclude that Dr. Miller was unqualified to testify under Rule 702, it did question his qualifications: Dr. Miller is not an expert in either oncology or pathology. Miller's opinion as to the cause of Christophersen's death was formed without consultation with oncologists or other cancer specialists. Dr. Miller's experience with cancer occurred during his residency when he assisted in a study of the immune system as affected by smoking and asbestos. Dr. Miller does not routinely treat cancer patients, nor has he ever treated a patient with a colon cancer of the type that affected Christophersen.

The trial court's concerns are understandable. As we stated in Peteet, "district judges and appellate courts must carefully review an expert's testimony to ensure that the expert has the necessary qualifications and a sufficient basis for his opinion." 868 F.2d at 1431; [Lavespere v. Niagra Machine & Tool, 910 F.2d 167, 176], (citing Peteet); see also In Re Air Crash Disaster at New Orleans, Louisiana, 795 F.2d 1230 at 1234-35 (5th Cir. 1986) ("Trial judges must be sensitive to the qualifications of persons claiming to be an expert."). We caution, however, that although credentials can be significant, they alone are not necessarily determinative. The questions, for example, do not stop if the expert has an M.D. degree. That alone is not enough to qualify him to give an opinion on every conceivable medical question. This is because the inquiry must be into actual qualification--sufficient to assist the trier of fact. [Viterbo v. Dow Chemical Co., 826 F.2d 420, 422 (5th Cir. 1987).] The trial judge here rightly scrutinized Dr. Miller's lack of specialized experience and knowledge. The district court did not base its disallowance of Dr. Miller's testimony on this issue, however. It preferred to rely on Rule 703 and the witnesses' methodology. We, therefore, move to those issues.

RULE 703

Dr. Miller premised his opinion that Marathon caused Christophersen's cancer on his belief that Christophersen had approximately a twenty-year history of "extensive exposure to nickel and cadmium fumes in the work place." The district court, pursuant to Rule 703, analyzed the underlying "facts and data" of Dr. Miller's opinion to determine whether it was based on the types of facts reasonably relied upon by experts in the field. Dr. Miller testified at his deposition that the level and duration of the patient's exposure are important considerations when evaluating the effect of exposure to a toxic substance.

The district court found that virtually all of the factual data concerning Christophersen's exposure to nickel and cadmium came from the affidavit of a Marathon employee named Edgar Manoliu (Manoliu), who described the fumes and Christophersen's exposure to them. The district court criticized this affidavit, however, as being inaccurate and incomplete. The Manoliu affidavit appears to have over-estimated the number of times per week Christophersen visited the manufacturing area, as well as the average length of time he would remain there on each visit. The affidavit was also devoid of any information about the type of fumes to which Christophersen was exposed or the type of fumes generated by the battery manufacturing process. We find particularly telling Manoliu's admission in his deposition that he did not know the chemical composition of the fumes nor the mix of chemicals in the impregnation and soak tanks.

Nor was Dr. Miller informed as to the physical facilities at the Marathon plant, including the size of the plant or the impregnation and soak area, or the ventilation available in these areas or in Christophersen's office. In addition, Dr. Miller did not always rely upon the accurate data that were contained in the affidavit. For example, the affidavit correctly indicated that Christophersen worked for fourteen years at the Waco plant before his death. Dr. Miller, however, based his opinion upon the assumption that Christophersen worked in the plant for twenty years. Thus Dr. Miller overestimated the duration of Christophersen's exposure by approximately fifty percent. Accordingly, accurate dosage and exposure information was not used by Dr. Miller.

Thus the court validly called into question the facts and data relied upon by Dr. Miller in forming his opinion. Slaughter v. Southern Talc Co., 919 F.2d 304 (5th Cir. 1990), reiterated the requirements under Rule 703: As a general rule, questions regarding the scientific bases of an expert's opinion "affect the weight to be assigned that opinion rather than its admissibility and should be left for the jury's consideration." Viterbo v. Dow Chemical Co., 826 F.2d 420, 422 (5th Cir. 1987). However, this general rule yields when "the source upon which an expert's opinion relies is of such little weight ... that [the] testimony would not actually assist the jury in arriving at an intelligent and sound verdict." Viterbo, 826 F.2d at 422. In such case, this court requires courts to examine the reliability of an expert's sources to determine whether they satisfy the threshold established by the rule.

Plaintiffs do not contest the district court's findings as to the deficiencies in the Manoliu affidavit. Rather, they argue that Dr. Miller stated in his opinion that dosage was less important when determining individual causation. Plaintiffs accordingly argue that any deficiencies in the underlying facts and data go to the weight of Dr. Miller's opinion rather than its admissibility. We disagree. If the dosage of the harmful substance and the duration of exposure to it are the types of information upon which experts reasonably rely when forming opinions on the subject, then the district court was justified in excluding Dr. Miller's opinion that is based upon critically incomplete or grossly inaccurate dosage or duration data.

As we have noted, Rule 703 seeks to ensure that the "facts and data" not otherwise admissible in evidence that form the basis of an expert's opinion are "of a type reasonably relied upon by experts in the particular field in forming opinions or inferences upon the subject." Although this rule is primarily directed toward permitting an expert to base his opinion on hearsay or otherwise inadmissible sources, Barrel of Fun, Inc. v. State Farm Fire & Casualty Co., 739 F.2d 1028, 1033 (5th Cir. 1984), the inquiry into the "types" of "facts and data" underlying an expert's testimony is not limited to the admissibility of that data. District judges may reject opinions founded on critical facts that are plainly untrustworthy, principally because such an opinion cannot be helpful to the jury.

The argument that Rule 703 addresses only generic facts and data and is unconcerned with the sufficiency and accuracy of underlying facts as they relate to the case at hand, will lead to the irrational result that Rule 703 requires the court to admit an expert's opinion even if those facts and data upon which the opinion are based are crucially different from the undisputed record. Such an interpretation often will render Rule 703 impotent as a tool for testing the trustworthiness of the facts and data underlying the expert's opinion in a given trial. Certainly nothing in Rule 703 requires a court to admit an opinion based on facts that are indisputably wrong. Even if Rule 703 will not require the exclusion of such an unfounded opinion, general principles of relevance will. In other words, an opinion based totally on incorrect facts will not speak to the case at hand and hence will be irrelevant. In any event such an opinion will not advance the express goal of "assisting the trier of fact" under Rule 702.

We do not of course say that Rule 703 requires that all facts and data underlying the opinion must relate perfectly to the record facts. As we have pointed out, only when the facts and data are critically inaccurate or incomplete, as determined by what other experts would or would not be willing to base opinions upon, would the facts and data lack the necessary requisites of Rule 703. The district court in this case did not abuse its discretion.


When analyzing the validity of an expert's methodology, we seek to determine whether it connects the facts to the conclusion in a scientifically valid way. We answer this question by applying the Frye test: whether the methodology or reasoning that the expert uses to connect the facts to his conclusion is generally accepted within the relevant scientific community.

In his deposition Dr. Miller stated that the kinds of evidence most often used to establish causation are human epidemiological studies, live animal testing, and in vitro testing. Defendants' experts agreed, but went a step further; they stated that the determination of the pathogenesis of a particular type of cancer requires clearly positive results from one or more of these types of testing. The district court was persuaded that it was inconsistent for Dr. Miller, on one hand, to conclude that these are the main methodologies and, on the other hand, to concede that he did not effectively rely on any of them. That epidemiological, animal, and in vitro studies are, as Dr. Miller said, the primary methods by which medical experts develop their theories of causation is not to say that Miller's methodology was invalid. The Frye question focuses on the proffered methodology alone and looks to the scientific community to determine if general support for that methodology exists.

The critical portion of Dr. Miller's opinion, as it relates to causation, is as follows: "the same sorts of chemicals and exposures that are associated with small-cell carcinoma of the lung are likely to be associated with small-cell carcinoma elsewhere in the body." Christophersen v. Allied-Signal Corp., 902 F.2d 362, 365-366 (5th Cir. 1990). Dr. Miller offered no scientific methodology to support this assertion. Dr. Sherwood Gorbach concluded that: Dr. Miller's presumption that nickel and cadmium have been associated with a certain type of cell in lung cancer and therefore should be associated with a similar type of cell in the colon has no support in medical science and is without foundation. The other defense expert, Dr. Richard Rudder, held the same view of Dr. Miller's methodology. All Dr. Miller had was a scientific hunch, which as far as the record shows, no one else shares. This was enough to support further investigation but was inadequate to support a judgment in favor of Christophersen. The district court found that "Dr. Miller's conclusion that a small cell carcinoma of the lung is likely to be associated with a small cell carcinoma located elsewhere in the body is 'without precedent in cancer epidemiology and is not scientifically correct.' " This finding of what is a scientifically correct conclusion is not for the district court. However, we cannot say that the district court erred in excluding Dr. Miller's testimony. To the contrary, the district court was within its discretion in concluding, albeit implicitly, that Dr. Miller's testimony failed to meet the third threshold test, the Frye test.


Because we find that Dr. Miller's testimony failed to clear either the Rule 703 or the Frye hurdle, we need not consider the district court's application of Rule 403.


The foregoing analysis demonstrates that this was not a "battle of experts" that would be improper for resolution on summary judgment. The district court's ruling that Dr. Miller's opinion was inadmissible was not manifestly erroneous. Because Dr. Miller's testimony was the only evidence of causation, the district court did not err in granting summary judgment for defendants. Affirmed.

CLARK, Chief Judge, concurring in the result:

The plain words of the carefully created, thoroughly reviewed, fully annotated Federal Rules of Evidence are for courts to follow, not embellish. I am perplexed by the fact that my colleagues in the majority embellish them and in dissent refuse to follow them.

The district court properly excluded expert opinion testimony that it correctly found to be substantially more prejudicial than probative. The majority per curiam approves exclusion, but does so by applying a home-made test for admissibility which not only disregards the plain meaning of the rules, but also builds in a headwind favoring exclusion of such evidence on a far broader basis than the rules permit....

RULE 702

Rule 702 defines the basic perimeter of expert opinion evidence: 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.

Obviously, a medical opinion as to causation would assist the trier of fact in this highly technical scientific case. As Judge Reavley's dissent establishes, it is equally obvious that Dr. Miller is a trained, experienced scientist who possesses specialized knowledge in toxicology and related fields. Both parts of the rule were satisfied. I agree with the district court and Judge Reavley that the summary judgment record establishes that Dr. Miller was qualified to testify as an expert under Rule 702.

The majority errs when it interprets Rule 702 to require the expert's opinion to assist the trier of fact. That is not what the rule says. Expert opinion testimony is admissible when "scientific, technical, or other specialized knowledge will assist the trier of fact to understand the evidence or to determine a fact in issue...." The advisory committee's notes make it clear that this rule focuses any question of assistance on the nature of the jury's factual inquiry rather than on the substance of the expert's testimony.

RULE 703

In two clear English sentences, Rule 703 addresses the permissible evidentiary bases for expert opinion evidence. The facts or data in the particular case upon which an expert bases an opinion or inference may be those perceived by or made known to the expert at or before the hearing. If of a type reasonably relied upon by experts in the particular field in forming opinions or inferences upon the subject, the facts or data need not be admissible in evidence.

As with Rule 702, the majority pays scant heed to Rule 703's plain language. The result is a confusing and internally inconsistent revision which gives almost no guidance to the district courts except to restrict the admissibility of expert opinion testimony in ways never intended by the Federal Rules of Evidence....

The first sentence of Rule 703 allows an expert to base an opinion or inference on facts or data perceived by or made known to the expert at or before the hearing. As the advisory committee's notes explain, this sentence allows three sources for the bases of an expert's opinion: (1) the expert's firsthand observations of facts or data, (2) evidence presented at trial, and (3) presentation of information or data to the expert outside of the courtroom and other than by the expert's own perception. Dr. Miller had no contact with Christophersen. He did not testify at trial. Thus, neither source (1) nor source (2) is applicable. Dr. Miller's testimony falls into the third category.

Rule 703 broadened the ambit of admissible evidence allowed at common law. "The traditional view ... has been that an expert may state an opinion based upon his firsthand knowledge or based upon facts in the record at the time he states his opinion, or based partly on firsthand knowledge and partly on the facts of the record." E. Cleary, McCormick on Evidence 14, at 31 (2d ed. 1976). This view barred experts from basing their opinions on facts or data presented to them outside of the courtroom other than such as were gained through the expert's own perception. The most significant concern underlying this view was hearsay. McCormick states it this way: A question is improper if it calls for the witness' opinion on the basis of reports that are not in evidence or are inadmissible as substantive evidence under the hearsay rule (without reciting their contents as hypotheses, to be supported by other evidence as to their truth). The essential objection seems to be that the jury is asked to accept as evidence the witness' inference, based upon someone's hearsay assertion of a fact which is, presumably, not supported by any evidence at the trial and which therefore the jury has no basis for finding to be true. Id., 15 at 34.

The second sentence of Rule 703 adopted a new approach to trustworthiness. It allows the expert to rely on inadmissible facts or data if they are of a type reasonably relied upon within the expert's community. See United States v. Williams, 447 F.2d 1285, 1290-91 (5th Cir. 1971) (en banc), cert. denied, 405 U.S. 954, 92 S. Ct. 1168, 31 L. Ed. 2d 231 (1972). Trustworthiness of facts or data not tested for admissibility is gained through the assurance that the expert's scientific community reasonably relies on them for the same purpose. See id. at 1290. For example, Rule 703 would permit a doctor to give a diagnostic opinion based upon facts contained in examination or test reports made by hospital technicians even if such reports were inadmissible hearsay, if it is shown that other doctors reasonably rely on such reports when forming similar opinions. Rule 703 says nothing more than that the facts or data need not be admissible in evidence if the reliability inquiry is otherwise satisfied.

If the facts or data are admissible, Rule 703 does not authorize exclusion of the expert opinion. If they are admissible, the inquiry ends, and nothing in Rule 703 authorizes exclusion of the expert's testimony. If they are not admissible, the district court must determine whether the reliability inquiry is satisfied. If it is satisfied, Rule 703 does not authorize exclusion. If it is not, the district court should exclude the testimony. No other reading is consistent with the plain language, history, and purpose of Rule 703.

Both sentences of Rule 703 apply just to the "facts or data" upon which an expert bases an opinion. Rule 703 does not address "methodology"--how the expert uses the facts or data to form an opinion. Rule 703 does not authorize a court to approve or disapprove the expert's conclusion. The words of Rule 703 allow use of facts or data "of a type reasonably relied upon by experts in the particular field in forming opinions or inferences upon the subject...." The court's inquiry is not whether experts in the relevant field would reasonably rely on the particular facts or data used by the expert witness. Nor does Rule 703 require a court to determine whether experts in the field would reasonably rely on the same type of facts or data to reach the expert witness's actual opinion. The rule is met if similar experts use facts or data of the same kind to form opinions on the subject in issue. Cf. Soden v. Freightliner Corp., 714 F.2d 498, 503 (5th Cir. 1983).

The majority opinion also approves the district court's Rule 703 analysis which criticizes Dr. Miller's facts and data as insufficient support for his conclusion that nickel and cadmium exposure caused Christophersen's cancer. The Rule 703 analysis is not concerned with whether the facts and data relied on by the expert support the expert's actual opinion. Even inadmissible facts or data are tested only to determine whether experts in the field would rely on the type of facts or data relied on by Dr. Miller in forming opinions on the subject of cancer causation.

The majority per curiam responds to this latter criticism with illogic. It reasons that giving plain meaning to the words "type" and "upon the subject" "will lead to the irrational result that Rule 703 requires the court to admit an expert's opinion even if those facts and data upon which the opinion is based are crucially different from the undisputed record." This stops the process too soon. The fact that Rule 703 does not preclude admissibility does not require that an improperly supported opinion must be admitted. Evidence that passes Rule 703 may be excludable under other rules. For example, the opinion might be irrelevant under Rule 401 or substantially more prejudicial than probative under Rule 403.

The majority says that giving the rule its plain meaning "often will render Rule 703 impotent as a tool for testing the trustworthiness of the facts and data underlying the expert's opinion in a given trial." This criticism grafts onto the rule a function that is incompatible with its language and purpose. The trustworthiness aspect of the reliability inquiry has nothing to do with whether the expert's facts or data provide sufficient support for the expert's opinion. Rule 703 does not say that the facts or data upon which an expert witness bases an opinion must supply reasonably reliable support for that opinion. Rather, the rule treats the reliability inquiry as a sufficient guarantee that an expert's inadmissible facts or data are sufficiently trustworthy to overcome the reasons why they are inadmissible. The rules deal with fundamentally unsupported but relevant expert opinions only in terms of probity versus prejudice under Rule 403, discussed below....

Because the district court's analysis of Dr. Miller's testimony was premised on an incorrect legal interpretation of Rule 703 that would deprive a jury of evidence it should be able to consider, I agree with Judge Reavley that exclusion on the basis of Rule 703 was manifestly erroneous and that the majority erred in basing affirmance on this rule.

RULE 403

In clear declaratory language, Rule 403 grants a limited power to exclude evidence. Although relevant, evidence may be excluded if its probative value is substantially outweighed by the danger of unfair prejudice, confusion of the issues, or misleading the jury, or by considerations of undue delay, waste of time, or needless presentation of cumulative evidence.

The district court's application of Rule 403 is essential to the outcome of the appeal. Individual rules cannot be read in isolation. Rule 403 is as much a part of the Rules of Evidence that govern this case as Rules 702 and 703. If it were not, I would agree with Judge Reavley and join his dissent. However, since it applies as strongly to expert opinion testimony as it does to any other evidence, see 1 J. Weinstein & M. Berger, Weinstein's Evidence 403[01], at 403-5 (1989), I would affirm the district court's decision to rely on it to exclude Dr. Miller's testimony.

Rule 403 allows a court to exclude relevant evidence when its probative value is substantially outweighed by the danger of unfair prejudice. An expert's opinion may be based on such erroneous facts or data, such proven unsound methodology, or such internally inconsistent reasoning that its probative value is minimal. Expert testimony may create a special kind of prejudice. When an opinion, especially one a lay person finds as arcane and speculative as cancer causation, is based on erroneous data, reasoning, or methodology, qualifying the opining witness as a medical expert carries a likely danger than the opinion will be substantially more prejudicial than probative. The fact that a witness is labeled an "expert" under Rule 702 would certainly be an improper basis for a jury's decision to believe the witness' opinion.

These principles introduce no new concepts into our jurisprudence. If an opinion is fundamentally unsupported, then it offers no expert assistance to the jury; and that lack of reliable support can render an opinion substantially more prejudicial than probative, making it inadmissible under Rule 403.

Judge Reavley's dissent maintains that, by excluding Dr. Miller's testimony, the district court took a fact issue from the jury. An analysis of probity versus unfair prejudice almost always depends to some extent on facts, but where undisputed proof supports the district court's conclusion as it does here, the issue is one properly decided by the court. When a permissible evidentiary ruling, supported by undisputed facts, excludes evidence, it takes away nothing that is proper grist for a jury.

In today's case, the undisputed record confirms that Dr. Miller relied on erroneous factual assumptions....

Dr. Miller's reasoning and methodology were also seriously deficient. He asserted that nickel and cadmium caused Christophersen's small cell colon cancer because they have been associated with small cell cancer of the lung despite the fact that he could cite no authoritative sources for this type of associative reasoning. The uncontradicted summary judgment evidence indicated that, without additional support, Dr. Miller's presumption that nickel and cadmium should be associated with cancerous cells in the colon because they have been associated with a similar type of cancerous cell in the lung is without precedent in cancer epidemiology and has no foundation in medical science. Moreover, Dr. Miller agreed that the determination of the pathogenesis of a particular form of human cancer requires human epidemiological studies, animal studies, and in vitro testing. He conceded that he had never seen an epidemiological or animal study demonstrating a causal association between exposure to nickel and/or cadmium and colon cancer.

I do not disagree with the dissent's view that Dr. Miller's testimony passed Rules 702 and 703. I very much disagree with its view that the court was required to admit his opinion testimony because the provisions of these two rules were met. The trial court was requested to review the evidence under Rule 403. He did so and concluded that Dr. Miller's testimony should be excluded.

Under the undisputed portions of the summary judgment record, the trial judge could find that Dr. Miller's opinion was supported only by his credentials and his persistent refusal to acknowledge the inadequacy of his methodology. The district court determined that the probative value of Dr. Miller's testimony was substantially outweighed by the danger of unfair prejudice. To reverse this Rule 403 ruling, we must find manifest error. There was none.

REAVLEY, Circuit Judge, with whom KING, JOHNSON and WIENER, Circuit Judges, join dissenting:

The author of the per curiam claims to "introduce no new concepts to our jurisprudence." Surely my colleagues know better, or at least they should know that their use of these concepts confuses the admissibility of evidence with the sufficiency of evidence, changes the rules of evidence without benefit of amendment, denies Mrs. Christophersen her right to trial by jury, and eliminates substantive rights in tort cases where federal courts have only diversity jurisdiction.

The en banc court perpetuates the district court's lack of study or appreciation of the record. Lengthy depositions were taken of three witnesses for the plaintiff. Dr. Waymon Johnston, an industrial engineering professor, testified to the negligence of the defendants in failing to warn of the deadly hazard of nickel and cadmium exposure. Christophersen's co-worker, Edgar Manoliu, testified about the conditions at the plant where Christophersen worked and his exposure to nickel and cadmium. And Dr. Miller testified that in his opinion it was that exposure which caused the colon cancer leading to Christophersen's death. The defendant presented four affidavits of medical experts who disagreed with the opinion of Dr. Miller and denied that scientific proof exists that cadmium and nickel fumes can cause small-cell cancer in the colon. These affiants for the defendants did not say that science has disproved the opinion of Dr. Miller; they did not even address his discussion of links between toxic carcinogens and genetic abnormalities; and they did not submit to depositions and the revealing cross-examination to which seven defense attorneys subjected Dr. Miller during his two-day deposition. Upon that basis and without recourse to a jury, the district court and this court choose to accept the position of the defendants' doctors and deny Mrs. Christophersen a trial....

Courts may, of course, exclude evidence that is patently unreliable and therefore offers no assistance to the jury. The language expressing such patent unreliability varies, but never signals testimony or assumptions that are merely controversial, debatable, questionable, unsettled, or suspicious. These terms connote weight and credibility. Instead, courts speak of testimony that is "almost entirely unreliable," reliance upon "assumptions devoid of any basis in the real world," opinions that are "abusive of the known facts" or "contrary to the proven facts," or so manifestly wrong as to offend common sense. If the record establishes a critical fact contrary to the expert's testimony, or if a court may take judicial notice of a fact that fatally contradicts the assumptions of an expert, then his or her testimony ought to be excluded....

Until today, we soundly limited the Frye doctrine to particular techniques, "novel scientific evidence," that reflect the factual context of Frye. To my knowledge, the Fifth Circuit has never excluded otherwise relevant evidence strictly on the basis of lack of general scientific acceptance. To do so would impose a significantly heavier burden of proof and persuasion on the offering party. See Peteet v. Dow Chem. Co., 868 F.2d 1428, 1433 (5th Cir. 1989) ("[T]he absence of a scientific consensus on a given theory does not affect the admissibility of an expert's opinion."), cert. denied, 493 U.S. 935, 110 S. Ct. 328, 107 L. Ed. 2d 318 (1990); Osburn, 825 F.2d at 915 (expert's opinion need not be generally accepted in scientific community to be sufficiently reliable and probative).

The district court of course did not cite to Frye or employ any kind of Frye analysis. The doctrine is doubtless alien to it in such a context. But the majority found that "the district court was within its discretion in concluding, albeit implicitly, that Dr. Miller's testimony failed to meet the third threshold test, the Frye test." How did they get there? I do not know, but they speak of "methodology."

If his study and the reasons for his opinion are Dr. Miller's "methodology," nothing distinguishes his methods from those of other experts. He examined the available information and literature, applied his experience and education, and gave an opinion with his reasons. If his reasons are his methodology, then here it is: (1) Christophersen had small-cell colon cancer that metastasized to his liver; (2) nickel and cadmium cause cancer; (3) some evidence suggests that nickel and cadmium act synergistically to produce cancer; (4) medical science so far has established specific links to lung, prostate, and renal cancers; (5) small-cell carcinoma appears to be the same cell (identical histology) regardless of its location in the body; (6) one of the physicians who examined Christophersen's colon biopsy material believed it was virtually identical to tumors of lung origin; (7) substances designated as "tumor promoters" are associated with a wide range of cancers, and there is some evidence that nickel is a tumor promoter; (8) one mechanism of nickel and cadmium carcinogenicity is alteration in DNA synthesis; (9) medical evidence relates small-cell cancer to abnormal alterations of genetic material; and (10) small-cell carcinomas, which are quite rare, are associated with toxic exposures.

None of the foregoing propositions abuses facts known to the district court or the majority. None is contrary to established scientific knowledge. Nor do we know specific cancers invariably associated with nickel and cadmium, or specific causes invariably associated with small-cell cancer. The only evidence in the record to substantiate the majority's Frye holding is the contrary conclusion of the defense experts, who do not even address critical aspects of Dr. Miller's disputed "methodology." And even had they refuted his reasoning with withering particularity, upon what basis can this majority infer the lack of "general acceptance," especially when the district court did not even address that issue? Are the affidavits of experts hired by the defense conclusive proof of "general acceptance"? Thus does the majority manage to introduce a new regimen, and simultaneously provide a case-study of its mischievous abuse....

Chief Judge Clark identifies the per curiam errors on Rules 702 and 703 but then does greater mischief with Rule 403. He misreads this record and misuses Rule 403.

Judge Clark writes that the "undisputed record" disproves Dr. Miller's factual assumptions. If that were so, Dr. Miller's opinion about facts unrelated to this case would not be relevant. And the opinion would not assist the fact finder. The opinion would be excluded under settled law. But how does this record disprove Dr. Miller's assumptions about Christophersen's exposure to toxic fumes? And how can Judge Clark enshrine as established fact that Dr. Miller delivered his opinion "without any accurate information on Christophersen's exposure"? One fact is truly uncontradicted: Christophersen was regularly exposed to the fumes and dust of this nickel-cadmium battery plant for over 13 years. Dr. Miller said he had enough information to support his causation opinion. That is the state of the record. By what rule or reason do we leap to judgment?

True, defense attorneys confronted Dr. Miller with all varieties of skepticism about Christophersen's exposure. But Judge Clark discloses his chosen result by converting defense attorney skepticism into the "fact that [Dr. Miller] formed his opinion without any credible exposure data." Then Judge Clark caricatures Dr. Miller as a man oblivious to conflicting evidence. Dr. Miller maintained that Christophersen's exposure was sufficient to cause, and in his opinion did cause, Christophersen's cancer and death. He did not say his opinion would be different only if there were no nickel and cadmium fumes; he simply stated that he might change his opinion if Christophersen had visited the soak room only once a month, and that his conclusion would certainly be different if there had been no exposure to toxic fumes....

If Judge Clark would override [the] fact issue with Rule 403, he fashions a rule with the following new and drastic effect. Judges may weigh contradictory evidence and exclude any proffered evidence considered unreliable. The judge's opinion about the contested evidence determines unreliability. The force of the proffered evidence on the very point at issue becomes the prejudice....

KING, Circuit Judge, with whom, REAVLEY, JOHNSON and WIENER, Circuit Judges, join dissenting: ...

Lest anyone misunderstand, at root this is not a case about the Federal Rules of Evidence, albeit that two of them may have been mangled in the process. It is instead about the outcomes in toxic tort cases. What the majority is saying is that in its view, the outcomes in toxic tort cases that have been left to the jury have too often been unacceptable. The majority's solution is to re-write the Federal Rules of Evidence, which have been on the books for more than half a century and which, implicitly, have too often been misapplied by "our able trial colleagues."

In terms of its practical impact, today's decision will require a penurious plaintiff represented by a personal injury lawyer on a contingent fee basis, already limited in investigative and expert resources, to pass a preliminary mini-trial on his expert's methodology. At such a mini-trial, the plaintiff will be exposed to all of the industry's heavy artillery, and may be at the receiving end of a district court ruling that will eviscerate his case. To compound the injury, because the majority has conveniently used the hook of the Federal Rules of Evidence, rather than openly announcing a new principle of federal substantive law, the district court's ruling will be reviewed under the manifestly erroneous standard. Plaintiffs attempting to establish liability in areas in which scientific methodology or reasoning is not yet well-established will face a nearly insurmountable burden. The result will be to deprive plaintiffs with possibly meritorious claims of a jury's assessment of their right to recovery.

Proposed Amendment to FRE 702

Testimony by Experts

If Testimony providing scientific, technical, or other specialized knowledge information, in the form of an opinion or otherwise, may be permitted only if (1) the information is reasonably reliable and will substantially assist the trier of fact to understand the evidence or to determine a fact in issue, and (2) the a witness is qualified as an expert by knowledge, skill, experience, training, or education to provide such testimony, may testify thereto in the form of an opinion or otherwise. Except with leave of court for good cause shown, the witness shall not testify on direct examination in any civil action to any opinion or inference, or reason or basis therefor, that has not been seasonably disclosed as required by Rules 26(a)(2) and 26(e)(1) of the Federal Rules of Civil Procedure.


This revision is intended to limit the use, but increase the utility and reliability, of party-initiated opinion testimony bearing on scientific and technical issues.

The use of such testimony has greatly increased since enactment of the Federal Rules of Evidence. This result was intended by the drafters of the rule, who were responding to concerns that the restraints previously imposed on expert testimony were artificial and an impediment to the illumination of technical issues in dispute. See, e.g., McCormick on Evidence, 203 (3d ed. 1984). While much expert testimony now presented is illuminating and useful, much is not, virtually all is expensive, if not to the proponent then to adversaries. Particularly in civil litigation with high financial stakes, large expenditures for marginally useful expert testimony has become commonplace. Procurement of expert testimony is occasionally used as a trial technique to wear down adversaries. In short, while testimony from experts may be desirable if not crucial in many cases, excesses cannot be doubted and should be curtailed.

While concern for the quality and even integrity of hired testimony is not new, Winans v. New York & Erie R.R., 62 U.S. 88, 101 (1858); Hand, Historical and Practical Considerations Regarding Expert Testimony, 15 Harv. L. Rev. 40 (1901), the hazards to the judicial process have increased as more technical evidence is presented:

When the evidence relates to highly technical matters and each side has shopped for experts favorable to its position, it is naive to expect the jury to be capable of assessing the validity of dramatically opposed testimony.

3 J. Weinstein & M. Berger, Weinstein's Evidence, 706[01] at 706-07 (1985).

While the admissibility of such evidence is, and remains, subject to the general principles of Rule 403, the revision requires that expert testimony be "reasonably reliable" and "substantially assist" the fact-finder. The rule does not mandate a return to the strictures of Frye v. United States, 293 F.2d 1013 (D.C. Cir. 1923) (requiring general acceptance of the scientific premises on which the testimony is based). However, the court is called upon to reject testimony that is based upon premises lacking any significant support and acceptance within the scientific community, or that otherwise would be only marginally helpful to the fact-finder. In civil cases the court is authorized and expected under revised Rule 26(c)(4) of the Federal Rules of Civil Procedure to impose in advance of trial appropriate restrictions on the use of expert testimony. In exercising this responsibility, the court should not only consider the potential admissibility of the testimony under Rule 702 but also weigh the need and utility of the testimony against the time and expense involved.

In deciding whether the opinion evidence is reasonably reliable and will substantially assist the trier of fact, as well as in deciding whether the proposed witness has sufficient expertise to express such opinions, the court, as under present Rule 702, is governed by Rule 104(a)....

Note: On June 20, 1992, the Standing Committee in charge of revisions decided to refer the proposed amendment to the (proposed) reactivated Advisory Committee on the Federal Rules of Evidence (appointed in 1993).


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