National Academy of Forensic Engineers

Transcription

1 NAFE and Kumho Amicus Curiae Brief of N AFE Decision of the US Supreme Court Update Following Decision.: 1/ National Academy of Forensic Engineers 1':' January,2001

2 For Further Information Contact: The National Academy of Forensic Engineers (NAFE) 174 Brady Avenue. Hawthorne. NY Marvin M. Specter, P.E., L.S. (Founding Presidem) NAFE Executive Director Website: Telephone: (toll free) 866-NAFE-ORG (numerically) Fax: (toll free) National Academy of Forensic Engineers (NAFE) ii

3 Contents NAFE and Kumho MM. Specter, P.E.. L.S.... v Amicus Curiae Brief of NAFE... ] Supreme Court Decision (March 23, 1999) Kumho Tire: An Update David V. Scott, Esq iii

4 NAFE and Kumho The NAFE played an important role in the recent U.S. Supreme Court Decision in a case titled "Kumho Tire co. v. Carmichael." Kumho interprets and modifies the law derived from an earlier case titled "Daubert v. Merrill Dow Pharmaceuticals Inc." The amicus brief filed by NAFE in Kumho was the only one of 19 amici briefs filed with the Supreme Court in this case which was cited by the court in its decision. The NAFE, emphasizing its lack of interest in the technical specificity of the testimony or the particular expert offering same in the underlying case, nevertheless made the strong point that the admissibility of expert engineering testimony should be determined by the trial court (judge) in a function sometimes called "gatekeeper." Also, most importantly, the determination as to admissibility of engineering testimony MIGHT be made utilizing some of the criteria of Daubert, but THE DAUBERT CRITERIA SHOULD NOT BE MANDATED FOR ALL ENGINEERING TESTIMONY. (In Daubert, a case involving birth defects alleged to have been caused by use of a particular drug by the birth mother, the court had set four specific criteria as to the reliability and admissibility of the biological research testimony received which were based on testing, publication and peer review and acceptance of the research). The NAFE was the only engineering organization taking this position, while opposing engineering organizations plus trade groups and others argued that Daubert criteria should govern the admissibility of expert testimony in all cases. In Kumho. the Supreme Court essentially determined in favor the NAFE recommendations. Marvin M. Specter. P.E.. L.S. (Founding Presidem) NAFE Execlllive Director January, 200 I v

5 No IN THE Supreme Court of the United States OCTOBER TERM, 1997 KUMHO TIRE COMPANY, LTD., eta/., Petitioners. v. Patrick CARMICHAEL, ETC., eta/. Respondents, On Writ Of Certiorari to the United States Court Of Appeals for the Eleventh Circuit BRIEF AMICI CURIAE OF THE NATIONAL ACADEMY OF FORENSIC ENGINEERS IN SUPPORT OF RESPONDENTS October 19, 1998 Alvin S. Weinstein, Ph.D., P.E.* 8 Lincoln Street Brunswick, ME (207) * Counsel of Record (additional attorneys listed on inside cover)

6 Larry E. Cohen 8710 East Vista Bonita Drive Scottsdale, AZ (602) Jerry J. Phillips University of Tennessee College of Law 151 West Cumberland Ave. Knoxville, TN (423) David V. Scott P.O. Box Bank St. New Albany, IN (812) Counsel 2

7 QUESTIONS PRESENTED 1. Whether all expert testimony is subject to the same four general observations" that dicta in Daubert suggested should be applied to novel scientific testimony? 2. Whether expert testimony based on a.. generally accepted" methodology that would be admissible under Frye should be excluded under Fed.R.Evid. 702, as interpreted by Daubert? 3

8 TABLE OF CONTENTS QUESTIONS PRESENTED... 3 TABLE OF AUTHORITIES... 6 IDENTITY AND INTEREST OF AMICUS CURIAE... 9 SUMMARY OF THE ARGUMENT ARGUMENT I. THE DAUBERT FACTORS SHOULD NOT RIGIDLY BE APPLIED TO ALL ASPECTS OF ENGINEERING II. III. IV. RIGID APPLICATION OF THE DAUBERT FACTORS TO ENGINEERING TESTIMONY FAILS TO GIVE SUFFICIENT WEIGHT TO THE IMPORTANCE OF EXPERIENCE AND THE ENGINEERING JUDGMENT BASED ON THAT EXPERIENCE THE METHODOLOGY EMPLOYED BY THE PLAINTIFFS'/ RESPONDENTS' EXPERT DEMONSTRATED ITS RELIABILITY WHEN VIEWED IN THE CONTEXT IN WHICH IT WAS GIVEN TESTIMONY THAT WOULD HAVE BEEN ADMISSIBLE UNDER A FRYE ANALYSIS SHOULD NOT BE EXCLUDED UNDER A DAUBERT ANALYSIS V. THE MISAPPLICATION OF THE DAUBERT STANDARD TO ENGINEERING TESTIMONY CONCLUSION

9 TABLE OF AUTHORITIES CASES Ambrosini v. Labarraque. 101 F.3d 129 (D.C. Cir. 1996) Carmichael v. Samyang Tires. Inc., 923 F. Supp (S.D.Ala. 1996) Carmichael v. Samyang Tire. Inc., 131 F.3d 1433, 1436 (lldlcir. 1997) Compton v. Subaru of America, Inc., 82 F.3d 1513, (loth Cir.), cert. denied, Ct. 611 (1996) Daubert v. Merrell Dow Pharmaceuticals, Inc., 509 U.S. 579 (1993)... passbn Frye v. United States, 293 F (1923)... passitn General Electric Company v. Joiner. 118S.Ct.512(1997) McKendall v. Crown Corporation, 122 F.3d 803 (9th Cir. 1997) United States v. Jones. 107 F.3d 1147, 1158 (6th Cit.), cert. denied, 117 S. Ct (1997)

10 RULES Fed.R.Civ.P. 26(a) Fed.R.Evid. 104 (a) Fed.R.Evid. 104 (b) Fed.R.Evid passiln OTHER AUTHORITIES Ronald W. Clark, EINSTEIN: THE LIFE AND TIMES (1971)....13, 14 Stephen A. Saltzburg, Daniel J. Capra, and Michael M. Martin, Commentary, U.S.C.S. Fed. R. Evid. 702 (1998)

11 IDENTITY AND INTEREST OF THE AMICUS CURIAE The National Academy of Forensic Engineers (NAFE), founded in 1982, is a Section 501 (c)6 non-profit organization of individual engineering practitioners, who are engaged in all fields of engineering. 1 Membership is highly selective and is open only to individual engineers who have demonstrated mastery and maintenance of the highest standards of professional education, training, knowledge, competence, and deportment. Memberships are not available on a corporate, organizational, or governmental basis. The typical NAFE member has thirty years of experience as an engineer. Many have advanced academic degrees. Each NAFE member is required to be both licensed under the laws of the state in which he practices and registered as a Professional Engineer (PE). Most members are licensed in more than one state and have multi-state PE registrations. Each member must belong to the National Society of Professional Engineers (NSPE) and to a national engineering technical society such as the American Society of Civil Engineers (ASCE), the American Society of Mechanical Engineers (ASME), or the Institute of Electrical and Electronics Engineers (IEEE). In addition to considerable engineering experience past the attainment of the PE license (which typically occurs in the fifth year after the B.Sc. level of engineering education), candidates for NAFE membership are required to demonstrate substantial experience in the application of their engineering knowledge in the jurisprudence system and to provide written recommendations from attorneys or judges familiar with their service to the courts, including their testimony subject to adversary cross examination. The NAFE is formally affiliated with the NSPE and with the Council of Engineering and Scientific Specialty Boards (CESB), which itself is sponsored by the major interdisciplinary engineering organizations of the United States: the NSPE; the Accreditation Board for Engineering Technologies (ABET), which reviews and accredits curricula in university schools of engineering; the National Council of Examiners for Engineering and Surveying (NCEES), which is the umbrella organization for state PE licensing boards and the PE license examination process; and the American Council of Consulting Engineers (ACEC), a multi-discipline trade organization of engineer designer/consultants. The NAFE is a charter member of CESB and, as authorized by CESB, certifies the individual members of NAFE as Diplomates in Forensic Engineering. Pursuant to Rule 37.6, Amicus states that no counsel for a party authored this brief in whole or in part, and that no person or entity other than Amicus and its counsel made any monetary contribution to the preparation or submission of this brief. The parties have granted blanket consent to the filing of briefs by amici supporting either party. The letters granting this consent are attached to this brief. 9

12 The purpose of the NAFE is to provide continuing education and encourage its members to provide objective, unbiased service and ethical practice to the courts and the legal profession. The NAFE does not favor defendants nor plaintiffs. NAFE believes that competent engineering analysis can often be of assistance to the trier of fact and can assist in the work of the legal system. Significantly, NAFE members work for - and testify on behalf of- corporations and defendants as often as do for individuals and plaintiffs. Dennis Carlson, the engineering expert whose testimony was deemed unreliable and inadmissible by the District Court in the case at bar, is not and has not been a member or NAFE, nor is he or has he been a candidate for membership in NAFE. To the best of Amicus' knowledge, information, and belief, no NAFE member has any direct economic interest in the outcome of these proceedings. Nonetheless, Amicus is very concerned with the petitioner's thesis that the Daubert criteria should be generaiiy or broadly applied to the practice of engineering in the legal system. SUMMARY OF THE ARGUMENT This Court showed great faith in the adversary system when it struck down the "general acceptance" requirement for the admissibility of scientific testimony. The use of the trial judges' power under Fed.R.Evid. 104 (a) and (b) to act as a gatekeeper applying the criteria of admissibility set forth in Daubert was necessary to monitor expert testimony which did not meet the general acceptance requirement as set forth in Frye v. United States, 293 F (1923) and its progeny. This Court's decision Daubert was intended to expand, not limit, admissibility of expert testimony. Criteria for admissibility of expert testimony crafted to insure reliability for scientific testimony addressed to issues not yet settled in the scientific community are not applicable to engineering and other practice-based disciplines. Where the expert testimony offered meets the more restrictive "general acceptance" criteria, a Daubert type analysis is neither necessary nor applicable. There are considerable differences between testimony addressing unresolved issues in epidemiology and an analysis of a tire to determine whether it failed due to a road hazard, misuse, or a manufacturing defect. The Daubert criteria cannot easily be applied to engineering testimony and other practice based disciplines because they fail to give proper weight to the importance of experience and engineering judgment. In the instant case, the trial court disaiiowed expert engineering testimony based on a visual analysis to 10

13 determine defect because it felt the opinion subjective and unreliable. The deductive process-of -elimination analysis used by Dennis Carlson, plaintiffs' /respondents expert, utilized to determine the tire failed due to a manufacturing defect was little different from a differential diagnosis utilized with great success in the medical profession. The methodology used by Mr. Carlson in his engineering analysis was the same used by others experienced in the analysis of tire failures, including the experts employed by the defendants. It is ironic that this Court's effort to break the shackles of Frye is now used as a basis to exclude testimony that would have been admissible under Frye. When the trial judge is required to rule on the merits of expert testimony he supplants the role of the trier of fact and places on the parties a burden of proof higher that required in civil cases. In the case at bar, Mr. Carlson, through a deductive process, determined that the most likely cause of tire failure was a manufacturing defect. He gave that opinion based on his training (he had a bachelor's and a master's degree in mechanical engineering from Georgia Tech), and his experience (he was a designer in the tire industry, and had investigated numerous tire failures as a consultant after he left the tire industry). The methodology he utilized for his analysis was the same as that used by engineers and others in the tire industry. The Eleventh Circuit's decision that the criteria for admission of scientific evidence should not apply to apply to opinion testimony that is based on skillor experience-based observations is correct and should be affirmed. ARGUMENT I. THE DAUBERT FACTORS SHOULD NOT RIGIDLY BE APPLIED TO ALL ASPECTS OF ENGINEERING NAFE members are proud of their academic awards, professional accomplishments, and high standards. Nevertheless, they do not believe that the reliability of all aspects of their work are properly measured by the four.. general observations" suggested by this Court in Daubert v. Merrell Dow Pharmaceuticals, Inc U.S. 579 (1993). Indeed, NAFE members are concerned that the so-called "Daubert factors" are being rigidly and inflexibly applied to areas of "scientific, technical, and specialized knowledge," Fed.R.Evid. 702, where they do not fit. Let us be clear. Members of NAFE have no quarrel with the Daubert Court's articulation of the now-famous "general observations" for assessing the reliability of scientific testimony. And NAFE members believe that it is entirely 11

14 appropriate for courts to apply those criteria to the kinds of cutting scientific theories and methodologies that were at issue in Daubert and General Electric Company v. Joiner, 118 S.Ct. 512 (1997). Both cases involved complex questions of epidemiology in which experts used animal studies to extrapolate a causal relationship between exposure to substances 2 and certain physical conditions suffered by the respective plaintiffs. But such advanced research is only a very small part of the practice of engineering and a very much smaller part of the practice of engineering that ends in litigation. The members of NAFE investigate tens of thousands of cases involving questions of the application of engineering technology. Products liability cases are only a small fraction of the totality of engineering related cases. Although the Daubert factors are suitable for some scientific testimony - particularly the kind of novel scientific testimony at issue in Daubert and Joiner - those factors are not suitable to all kinds of knowledge and in all cases and certainly should not be applied rigidly in every case and to all types of knowledge. Although petitioners and their amid urge this Court to hold that the Daubert factors should be applied across the board to all types of scientific, technical, and specialized knowledge, NAFE members think that such a ruling would impose a higher standard on the reliability of testimony than is often used in the actual practices of most professions and intellectual disciplines, particularly engineering. As a result, the application of the Daubert factors to all sorts of testimony in all kinds of cases would lead to the exclusion of valuable, valid, and reliable insights. NAFE members do not know how the framers of Fed.R.Evid. 702 would have defined "scientific, technical, and specialized knowledge" or how they would have defined any one of those terms. Amicus suggests, however, that there is no one right answer, no single definition, that describes all scientific enterprises, and no simple interpretation that fits all cases. Put simply, there is Science and there is science. There is Engineering and there is engineering. Scientists and engineers do not apply the same yardstick in measuring the quality, validity, and reliability of all work that scientists and engineers do. Amicus suggests that it would be folly for the Court to impose a universal standard when scientists and engineers use different ones, and folly for tile Court to impose higher standards than scientists and engineers do in a particular instance or case. 2 In Daubert, it was the relationship between Bendectin and birth defects; in Joiner, the relationship between PCB and its derivatives and cancer. 12

15 Although petitioners and their amici suggest that all knowledge and all science is a single, gigantic, undifferentiated mass and that one standard does, can, and should be applied to testing the reliability of all testimony proffered under Fed.R.Evid in brief, that "one size fits all" - scientists and engineers everyday apply different standards to different aspects of their work. Indeed, the same scientist may often apply different standards to different aspects of his or her work, even on the same day. Albert Einstein illustrates this point very well. Although Einstein is today renowned as the century's most accomplished theoretical physicist, it is generally forgotten that "his first regular job" was much more prosaic: he was an "engineer, Class II at the [Swiss] Federal Patent Office," Ronald W. Clark, EINSTEIN: THE LIFE AND TIMES 68 (1971), a position he held from 1902 to 1908, after he had "completed [his doctoral] thesis" in physics, and while he was '"looking for a position as an assistant lecturer at some university,"' and before he became world-famous. /d. at 68, 69 (citation omitted). During these seven years Einstein led two very different scientific lives. As he described it contemporaneously to a friend. the patent job gave him '"eight hours of work"' and... eight hours of idleness"' everyday. /d. at 75 (citation omitted). He characterized his daytime work as a '"practical profession, "id.; his biographer said that Einstein.. saw it mainly as a useful base from which he could begin the self-imposed task of exploring the nature of the physical world." /d. at 71. "Each morning" Einstein "unobtrusively trott[ed]... to the Patent Office," where he examined, tested, and analyzed "inventions, ideas, and proposals [which] consisted largely of suggestions for practical, utilitarian, basically simple, and often homely applications of technology to the mundane affairs of everyday life," such as innovations for "typewriters and cameras [and] engineering devices... /d. at 76, "Each evening" Einstein unobtrusively "return[ed] to his lodgings," where he "set himself down in a quiet corner to discover the laws of nature." /d. at 76. The standards Einstein employed in his vocation and avocation were as different as day and night. By day, at the Patent Office, Einstein was "required to form an immediate opinion" on new patents. /d. at 70 (emphasis added). "Success was the yardstick and if success were attained by a leavening of byguess-and-by-god to formal scientific work, [the Patent Office's Chief Engineer] saw little harm in that." /d. at

16 At night, in his lodgings, Einstein undertook Gedanken Untersuchungen - "Thought Experiments" - using nothing more than pencil and paper, while he ruminated over and over on a few deceptively simple questions. Indeed, one such question had preoccupied him for more than ten years, i.e., since 1894, when he was sixteen: what would the world look like, he wondered, if one could travel through space and time while riding on a beam, and at the speed of, light. /d. at Although he answered that question, at least to his own satisfaction, by devising the Special Theory of Relativity, he did not publish that theory until 1905, /d. at 74, , , and that theory did not receive its first, provisional scientific validation through experimental testing until /d. at , Developing the Special Theory, which, of course, contains the celebrated equation E=mc 2, "required" Einstein to do the opposite of what he did during his daytime, '"practical profession,'" that is. not to "form an immediate opinion on the usefulness of "mundane" things,'' /d. at 75,70,74, but to analyze and resolve seemingly and hitherto irreconcilable contradictions among fundamental principles of physics, as exemplified by Newton's Laws of Motion and Lord James Clerk Maxwell's equations of electromagnetism./d. at It seems obvious to NAFE members that Einstein judged the work of theoretical physicists, like Newton and Maxwell, on the one hand, and the work of inventors who sought patents on the basis of their practical application of wellestablished physical theories, on the other hand, by vastly different standards. He subjected the former to endless and exacting scrutiny. He measured the latter more quickly and more leniently: as noted above, "[s]success was the yardstick and if success were attained by a leavening of by-guess-and-by-god to formal scientific work, [the Patent Office's Chief Engineer] saw little harm in that." /d. at 69. It also seems obvious that the different types of work that Einstein undertook also were tested by different standards. His superiors at the Patent Office assayed his work for speed and "useful[ ness],'' id. at 73, not for deliberation and thoroughness. By contrast, his fellow theoreticians assayed his equations and proofs for their accuracy, predictive value, and completeness. Although. Einstein's Special Theory received initial experimental confirmation in fourteen years after Einstein published it, that theory remains controversial to this day, at least as to its completeness. Indeed, Einstein devoted the final four decades of his life unsuccessfully trying to devise a more accurate and complete Unified Field Theory, one that would "'connect gravitation and electricity."' /d. at 493 (citation omitted). See /d. at , It is obvious that not every scientist or engineer is an Einstein. It is equally obvious that almost any scientist or engineer can and often does wear 14

17 different hats at different times or even at the same time. Thus, although as the National Academy of Engineering and the Rubber Manufacturers Association are correct in explaining that tire failures can be subject to very sophisticated, comprehensive, and time-consuming forms of analysis, this hardly means that all such failures either routinely are or routinely should be subjected to the most exacting scrutiny. Nor does the fact that tire failures can be tested by the gold standard mean that anything less than the gold standard is beyond the scientific pale. The experience of NAFE members shows that the kind and level of engineering/scientific analysis undertaken by a given professional at a given time varies, necessarily, with the question he is asked to answer. As Carlson explained, when he was employed at Michelin he was asked different types of questions and given different types of assignment at different times. Sometimes he was asked to discover and explain why a particular tire, such as one that had been returned to a dealer by a disgruntled customer, had failed. At other times, he was given the task of analyzing why a particular brand, model, or design of tire was repeatedly failing. The stakes, for the company, were usually much greater for the latter than for the former and, understandably called for a different, higher, more sophisticated, lengthier, and more expensive level of testing and analysis. A. The Daubert Court Limited Its Analysis of Fed.R.Evid. 702 to a "Scientific" Context In Daubert, this Court limited its analysis of Fed.R.Evid. 702 to that portion that refers to.. scientific" knowledge:.. Rule 702 applies to technical, or other specialized knowledge.' Our discussion is limited to the scientific context because that is the nature of the expertise offered here." Daubert, 509 U.S. at 590, n. 8 (emphasis added)... In a case involving scientific evidence, evidentiary reliability will be based upon scientific validity. "/d., 509 U.S. at 590, n. 9 (emphasis in the original). Amicus respectfully submits that in cases involving engineering evidence, evidentiary reliability should be based on engineering validity. There is a significant difference between expert testimony concerning matters not yet settled in the scientific community and testimony concerning the cause of a tire failure. The Daubert analysis, incorporates the basic elements of the scientific method. Daubert, 509 U.S. at The scientific method is used to prove conclusive facts by reproducible experimentation. A party's burden in a civil case is considerably less than that. Additionally, such experimentation and the review process attendant thereto is not feasible in most engineering cases. 15

18 II. RIGID APPLICATION OF THE DAUBERT FACTORS TO ENGI NEERING TESTIMONY FAILS TO GIVE SUFFICIENT WEIGHT TO TILE IMPORTANCE OF EXPERIENCE AND THE ENGI NEERING JUDGMENT BASED ON THAT EXPERIENCE. An engineer's ability to apply his or her education comes with experience. Basic academic knowledge becomes useful to an engineer through an understanding, gained by experience, of the relationships between materials as they act in the real world, and the interplay of energies and forces as they actually govern the performance of devices and processes. It is no accident that industrial corporations, government agencies, and engineering firms alike prefer to hire engineers who have received only baccalaureate degrees, rather than advanced degrees, not because the private and governmental organizations that hire new engineers discount the value of advanced academic training, but rather because they believe such training is useful only if newly-minted engineers have been "seasoned" with experience. Thus, these organizations hope and expect (even where they do not require) that engineers with B.Sc. degrees will earn advanced degrees through part-time "after work" studies. The competent practice of engineering, the art of engineering, is largely dependent upon experience gained in the practice of engineering and should not be excluded from expert testimony. In many respects it is the most valuable information that the engineer can bring to the courtroom. To mandate a single set of overriding criteria (devised as test standards for acceptance of novel theories related to biological/medical research) and to require the application of those criteria to engineering testimony would deny the trier of fact in engineering related cases the competent judgment of engineers engaged in the actual practice of engineering. NAFE opposes the application of Daubert to engineering testimony, excepting those very few matters which involve new and novel theory originally researched. In the vast majority of engineering cases the testing process mandated in original or novel research is simply not feasible, because the object at issue is unique or has failed or been impaired or is incidental to some process leading to accident or failure and is not reasonably reproducible. Double blind experiments followed by peerreviewed publication and verification by other researchers is an admirable process for testing of novel scientific/medical theory, but unrelatable to the real would of accidents and material or system failures where most engineers work. Also, such extensive experimentation, if required within the time strictures and economic limitations of the legal system as a sine qua non for engineering testimony, simply would prevent the availability of competent testimony to assist the trier of fact. It appears that this would subvert and defeat the intent of Fed.R.Evid

19 The courts, by applying sensible constraints on engineering testimony in accord with the more restrictive Frye doctrine, would be able to provide the trier of fact with the engineering assistance that they need and can best use. That some individual expert might seek to venture beyond his competence is a failing not to be denied, but is probably less (not more) prevalent in the domain of engineering testimony in the courts than by others elsewhere in our society. However, the engineering profession through professional licensing (State PE registration) which is revocable for violation of legally mandated codes of conduct and by exposition and peer pressures tends strongly to minimize improper actions by engineers. The engineering profession looks with pride and respect to the "Code of Ethics for Engineers" of the National Society of Professional Engineers (NSPE), the.. Code of Ethics" of the American Society of Civil Engineers (ASCE), and numerous such codes set forth by literally hundreds of disciplines and specialty-specific engineering societies. A. ENGINEERING CONSIDERATION IN DESIGN Although there is no question that in many, if not most, design considerations, the engineer may or will make use of well-established analytical techniques, methods, tests. and mathematical tools to determine certain physical characteristics of a product, device, or structure, that is not the end of the design process. It is usually only the beginning. Unlike science, engineering always involves (except for a few instances not relevant here) a balance of competing trade-offs that are essential in order to complete the design of the product, the device, or the structure. Design constraints. such as usefulness, weight, strength, cost, manufacturability, serviceability, safety, foreseeability of misuse, and intended uses, can be incompatible requirements of a component. For example, not only will adding more safety devices increase the cost of the item, but the utility of the product may be eroded or the serviceability may be compromised. If the strength is increased to accommodate a greater range of foreseeable misuses, the cost and usefulness may be compromised or additional hazards may be introduced. Thus the design process ends only when and if the engineer has reached a balance of these competing considerations using, perhaps, reduction of hazards from all reasonably foreseeable use situations, as the premise for completing the design. Alternatively, the engineer may be constrained to design at the lowest possible cost or the least possible weight, or complete the design using some other constraint. 17

20 Regardless of the constraint the engineer chooses or is required to use to complete the design, it is not based on a "scientific" methodology. And when the allegation is that of a design defect or a manufacturing defect, the battleground between opposing experts is not the "scientific" principles used to calculate the strength of a critical component, for example, but, rather the constraint chosen to complete the design, e.g. the cost of the item or, perhaps, the failure to address an appropriate range of foreseeable uses or the product's failure to meet design specifications. There are no "peer-reviewed" publications that discuss the "proper" means of balancing completing design constraints. It is a matter of postulating the characteristics of the product users, together with the uses and misuses to which they put the product within the environments that the product foreseeably will be used, so as to reduce or eliminate the resultant risks of injury. The plaintiffs expert will argue for a different balance of those competing considerations that leads to that expert's proposed alternative to the existing design. The ability of a plaintiffs expert to answer relevant questions regarding such matters as altered cost, utility, or marketability, associated with the proposed design alternatives, are most appropriately the subject for cross-examination, not for barring the testimony in the first place. As long as the expert has satisfied the court that she/he has the appropriate qualifications to address the relevant issues and that he/she employs the standard methodologies used in the field to answer the particular question posed in the case, the expert should be permitted to testify. Engineering judgment always plays an important role in engineering design and analysis. Two engineers with similar training and backgrounds can look at the same problem, apply the same methodology, and have different opinions as to the solution. When that occurs in a litigation context, the best solution is the one espoused by this Court in Daubert: "Vigorous cross-examination, presentation of contrary evidence, and careful instruction on the burden of proof are the traditional and appropriate means of attacking shaky but admissible evidence." Daubert, 509 U.S. at 596. The adversarial system is better equipped today to deal with experts who offer questionable testimony than it ever has been. This is the information age. With a key stroke one can find an immense amount of information about a potential expert witness. Listing of prior testimony and prior publications are part of the required disclosure of expert witnesses under Fed.R.Civ.P. 26(a). Access to transcripts, patent searches, literature searches, and other background investigation is as close as the computer on a counsel's or consultant's desk. 18

21 III. THE METHODOLOGY EMPLOYED BY THE PLAINTIFFS'/ RESPONDENTS' EXPERT DEMONSTRATED ITS RELIABILITY WHEN VIEWED IN THE CONTEXT IN WHICH IT WAS GIVEN. This case exemplifies the problems that can be created when a court attempts to analyze a particular method of analysis without adequate knowledge of the methodologies utilized in the particular field in which the opinion is being offered. Amicus shares Chief Justice Rehnquist's view that Rule imposes on [trial judges] neither the obligation nor the authority to become amateur scientists in order to perform that role." Daubert, 509 U.S. at Here the methodology employed by Mr. Carlson was the same as employed by others in his field. In the case at bar, the expert, through a deductive process, determined that the most likely cause of a tire failure was a manufacturing defect. He gave that opinion based on his training (he had a bachelor's and a master's degree in mechanical engineering from Georgia Tech), and his experience (he was a designer in the tire industry, and had investigated numerous tire failures as a consultant after he left the tire industry). The methodology he utilized for his analysis was the same as that used by engineers and others in the tire industry, including the defendant's own experts. The trial court approved of Carlson's.. process-of-elimination form of proof," recognized that he employed a methodology to reach his conclusions, but simply did not believe the method was reliable. Carmichael v. Samyang Tires, Inc F. Supp (S.D.Ala. 1996). Conversely, the Eleventh Circuit approved of the same methodology: Carlson rests his opinion on his experience in analyzing failed tires. After years of looking at the mangled carcasses of blown-out tires, Carlson claims that he can identify telltale markings revealing whether a tire failed because of abuse or defect. Like a beekeeper who claims to have learned through years of observation that his charges always take flight into the wind, Carlson maintains that his experiences in analyzing tires have taught him what.. bead grooves" and.. sidewall deterioration., indicate as to the cause of a tire's failure. Carmichael v. Samyang Tire. Inc F.3d 1433, 1436 (if' Cir. 1997). The Eleventh Circuit came to its conclusion based on its observation that the petitioners' experts had relied on the same markings and analytical methodology for their analysis as Mr. Carlson did for his. 131 F.3dat 1436n. 8. Thomas M. Dodson, Samyang's expert, 923 F. Supp. at has made it quite clear that the tools used to determine why a tire failed are not sophisti- 19

22 cated, "tread measuring device, hand held magnification, cameras and things of that nature for documentation purposes. Nothing terribly sophisticated." Deposition of Thomas M. Dodson, Vasquez v. Uniroyal Goodrich Tire Co.,Jnc., 138 Judicial Dist. Ct, Cameron County, Tex., Cause No B Oct. 15, 1997) at 6. (A true and correct copy of this deposition has been lodged with the Clerk of the Court has Exhibit A to this Brief). A: Well, I can't speak for the whole tire industry, but for anybody I've ever come in contact with, the visual/tactile examination is usually the technique of choice. Q: And it is accepted as a reliable and accurate way to determine? A: Depends on who's doing the examining, sir. Q: That's right. A: If used properly I think it is a valid technique. Q: So if a person is qualified, has the experience such as your experience, the technique certainly can be reliable and accurate in determining the causes of a tire failure? A: I think the technique, if used properly, comparison/observation to conclusion technique is a valid technique. I can't address any particular individual using that technique without some knowledge of who that individual is. You know, some people take the tool and use them totally inappropriately, doesn't make the tools bad. ld. at Tellingly, neither at trial, before the Eleventh Circuit, or before this Court, have petitioners' (or their amici) controverted Carlson's assertion that their experts used the same methodology that he did. The most they have said is that other, better, more accurate, more reliable tests are available - not that such tests are ever used in the context of the question to experts for both parties in this case: what caused the failure of the particular tire that exploded on the Carmichael van - customer abuse or a design or manufacturing defect? The fact is that the methodology Mr. Carlson used is identical to that used in the tire industry generally to analyze tire failures. Amicus has lodged with the Clerk of Court affidavits, and trial and deposition transcripts providing the sworn testimony of individuals from the tire industry, experts testifying on behalf of the tire industry and other tire failure experts, all indicating that they use a visual technique and the process-of-elimination as their primary method to determine whether a tread separation and resulting tire failure occurred do to defects in manufacture or design verses consumer abuse or a road hazard. 20

23 In addition, Amicus has also lodged with the Clerk, as Exhibit B, the affidavit of Mr. H. R. Baumgardner. Mr. Baumgardner spent twenty-seven years of his professional life as a tire engineer at Firestone Tire and Rubber Company. He has considerable experience in tire design, industry-based analysis of tire failures in both a test environment and field environment, and forensic analysis of tire failures in a litigation setting. According to Mr. Baumgardner's affidavit: 7. A determination of whether tread separation or tread belt separation in a steel belted radial tire is due to manufacturing, design defects, or abuse is a relatively simple undertaking for experienced tire engineers that is accomplished primarily by visual and tactile inspection. Infrequently x-ray examination of a tire is utilized to confirm findings on a visual examination. 8. Tire engineers and tire rubber chemists, when analyzing the results of their own experimental test tires run on laboratory and fleet tests, rely almost entirely on visual examination of the failed surfaces for determination of the cause of the failure. I was present for thousands of reports by Firestone engineers and chemists who reported to management regularly at Fleet Meetings. Virtually none of these reports required more extensive analysis or examination. The criterion was usually did the tire perform as expected and if it failed, where did it fail and was a construction weakness evident. Baumgardner Aff., at 1-2 (emphasis added). As Mr. Baumgardner indicates, determining the exact nature of manufacturing defect can be elusive for several reasons. Conversely, the lack of adhesion resulting in tread and outer belt separation of radial tires is a "manufacturing defect that has caused many serious and fatal accidents." 12. This manufacturing defect can most often be determined by the process of elimination whereby the potential causes of tread separation are systematically eliminated by visual examination. If an examiner finds no evidence of external damage or other external causes of tread separations, such as problems of extreme overloading or under inflation, etc., and evidence is present of propagation of the separation in the normal service one can conclude that such tread separation is the result of improper adhesion as a result of a manufacturing defect. Baumgardner Aff., at 2. 21

24 One characteristic Mr. Carlson, Mr. Baumgardner, and Mr. Dodson have in common is that they are well qualified. Mr. Carlson's qualifications are not questioned here. An expert's outstanding qualifications provide "circumstantial evidence" that the expert has employed a sound methodology. Ambrosini v. Labarraque, 101 F.3d 129 (D.C. Cir. 1996) The Official Comments to Fed.R.Evid.702, at page 13 makes the pragmatic observation that the lesson to be learned from the cases following Daubert is: "If the methodology is good enough for the real world, it is good enough for a trial." Stephen A. Saltzburg, Daniel J. Capra, and Michael M. Martin, Commentary, U.S.C.S. Fed. R. Evid. 702 (1998), at 13. IV. TESTIMONY THAT WOULD HAVE BEEN ADMISSffiLE UNDER A FRYE ANALYSIS SHOULD NOT BE EXCLUDED UNDER A DAUBERT ANALYSIS. It is ironic that testimony which would have met the test in Frye v. United States, 293 F (1923), should be excluded under a Daubert analysis. The rules for admissibility set forth in Frye differ from Rule 702 only to the extent Frye requires that the proffered testimony represent deductions made from principles which had "gained general acceptance" in a particular field. The rule is that the opinions of experts or skilled witnesses are admissible in evidence in those cases in which the matter of inquiry is such that inexperienced persons are unlikely to prove capable of forming a correct judgment upon it, for the reason that the subject-matter so far partakes of a science, art, or trade as to require a previous habit or experience or study in it, in order to acquire a knowledge of it. When the question involved does not lie within the range of common experience or common knowledge, but requires special experience or special knowledge, then the opinions of witnesses skilled in that particular science, art, or trade to which the question relates are admissible in evidence. Numerous cases are cited in support of this rule. Just when a scientific principle or discovery crosses the line between the experimental and demonstrable stages is difficult to define. Somewhere in this twilight zone the evidential force of the principle must be recognized, and while courts will go a long way in admitting expert testimony deduced from a well-recognized scientific principle or discovery, the thing from which the deduction is made must be sufficiently estab- 22

25 lished to have gained general acceptance in the particular field in which it belongs. Frye, 293 F. at If Mr. Carlson's opinions are analyzed in the context of the field of mechanical engineering and the analysis of tire failures, it is quite clear that Mr. Carlson's opinions were made by "deductions" based on principles that find "general acceptance" in the field of mechanical engineering. The trial court failed to give sufficient weight to the ability of an expert to express an opinion to a reasonable engineering probability based solely of the use of his senses. Mr. Carlson's methodology to determine whether tire failure was caused by a manufacturing defect verses a road hazard or abuse is little different from the differential diagnoses utilized by physicians. It does not make sense that a rule that was intended to expand the admissibility of expert testimony is now being used to exclude testimony that would never have been challenged under Frye. The irony, that parties would claim that Daubert "raised the bar of admissibility," was specifically addressed by the Sixth Circuit in United States v. Jones, 107 F.3d 1147, 1158 (6th Cir.), cert. denied, 117 S. Ct (1997). As we implicitly recognized in Berry [v. City of Detroit, 25 F.3d 1342, (6th Cir. 1994)], Daubert does not create a new framework for analyzing proffered expert testimony based upon "technical, or other specialized knowledge." Daubert provides a "flexible" framework to aid district courts in determining whether expert scientific testimony is reliable. If that framework were to be extended to outside the scientific realm, many types of relevant and reliable expert testimony - that derived substantially from practical experience - would be excluded. Such a result truly would tum Daubert. a case intended to relax the admissibility requirements for expert scientific evidence. on its head. Jones, 107 F.3d at 1158 (emphasis supplied.) V. THE MISAPPLICATION OF THE DAUBERT STANDARD TO ENGINEERING TESTIMONY Amicus' concern about the rigid application of the Daubert principles to engineering testimony is best evidenced by the result in a case not currently before the court. In McKenda/1 v. Crown Corporation, 122 F.3d 803 (9th Cir. 23

26 1997), the trial court had, based on a Daubert challenge, excluded the testimony of a mechanical and metallurgical engineer who had been working in the field of product design, product development, and product safety for over 50 years and had been a professor of mechanical engineering for 33 years. The case did not concern any novel scientific issue. It was a products liability case involving a specialized version of an industrial forklift truck called a "stockpicker." The engineer had offered the opinion that the stockpicker was defectively designed because it did not adequately protect the operator. He proposed an interlock barrier to be installed between the operator and the load. The engineer's testimony was excluded by the trial court because the court felt that the engineer had not sufficiently demonstrated that the proposed gate was feasible, that it would not impede the pickers proposed use, and that it would increase the overall safety of the vehicle. McKendall. 122 F.3d at 805. The Ninth Circuit correctly reversed the trial court, finding the principles of Daubert inapplicable to the proffered testimony: McKendall does not contend that Siegel's testimony would withstand an application of the Daubert factors. Rather, he argues that the district court erred in applying the Daubert factors to Siegel's testimony since Siegel's testimony was not based on "scientific" knowledge. McKendall asserts that Siegel's testimony is based on his experience as a mechanical engineer who has investigated hundreds of forklift accidents. He argues that Siegel has "technical, or other specialized knowledge" described in Rule 702, and to which the Daubert factors, applicable to scientific knowledge, do not apply. Thus, he proposes that Siegel's testimony should have been admitted under Rule 702, as Siegel demonstrated through experience, training, and education his familiarity with forklifts. Furthermore, he argues, this technical or other specialized knowledge would have assisted the trier of fact to understand the evidence and to determine facts in issue, consistent with Rule 702. McKendall, 122 F.3d at 806. Significantly, unlike the testimony of the plaintiffs' experts in Daubert and Joiner, the engineering testimony offered in McKendall involved basic principles of mechanical engineering design that were neither novel nor untried. See also Compton v. Subaru of America, Inc., 82 F.3d 1513, (loth Cir.), cert. denied, 117 S. Ct. 611(1996) (defendant manufacturer tried unsuccessfully to use Daubert criteria to exclude clearly competent expert testimony submitted 24

27 by an aerospace and mechanical engineer who had 22 years experience in automotive design, where the issue was the design of the roof and its failure to provide acceptable occupant protection). McKenda/1 and Compton are but a few of the many instances trial judges have struggled trying to apply a standard developed to monitor novel scientific evidence to real world every day use of engineering experience and judgment. The analysis should fit the discipline from which the opinions are drawn. CONCLUSION This Court should affirm the decision of the Eleventh Circuit Court of Appeals concluding that the Daubert factors do not form an appropriate basis for evaluating the admissibility of opinion testimony that is based on skill or experience based observations. Engineering testimony which would been admissible under the more restrictive Frye standard should not be excluded. Amicus respectfully urges this Court to recognize the important role that experience and engineering judgment play in opinion testimony concerning engineering matters. In cases involving engineering evidence, evidentiary reliability should be based on enkineering validity. Respectfully submitted, Alvin S. Weinstein, Ph.D., P.E. COUNSEL OF RECORD for Amicus Curiae National Association of Forensic Engineers 8 Lincoln Street Brunswick, ME (207)

28 No IN THE Supreme Court of the United States KUMHO TIRE COMPANY, LTD., eta/., Petitioners, v. Patrick CARMICHAEL, ETC., eta/. 119 S. Ct. 1167; 1999 U.S. LEXIS 2189; 67 U.S.L.W. 4179; 50 U.S.P.Q.2D (BNA) 1177; 99 Cal. Daily Op. Service 2059; 1999 Colo. J. C.A.R December 7, 1998, Argued March 23, 1999, Decided 27

29 NOTICE: [* 1] The LEXIS pagination of this document is subject to change pending release of the final published version. PRIOR HISTORY: ON WRIT OF CERTIORARI TO THE UNITED STATES COURT OF APPEALS FOR THE ELEVENTH CIRCUIT. DISPOSITION: 131 F.3d reversed. CORE TERMS: tire. reliability, scientific, expert testimony. tread, reliable, methodology, specialized, engineering, bead, gatekeeping, admissibility, wear. shoulder, expertise, tactile, visual, overdeflection, inspection, latitude, carcass, evidentiary. particular case, discipline, flexible, puncture, rim, peer review. inadequately. flange SYLLABUS: When a tire on the vehicle driven by Patrick Carmichael blew out and the vehicle overturned, one passenger died and the others were injured. The survivors and the decedent's representative, respondents here, brought this diversity suit against the tire's maker and its distributor (collectively Kumho Tire), claiming that the tire that failed was defective. They rested their case in significant part upon the depositions of a tire failure analyst, Dennis Carlson, Jr., who intended to testify that, in his expert opinion, a defect in the tire's manufacture or design caused the blow out. That opinion was based upon a visual and tactile inspection of the tire and upon the theory that in the absence of at least two of four specific, physical symptoms [*2] indicating tire abuse, the tire failure of the sort that occurred here was caused by a defect. Kumho Tire moved to exclude Carlson's testimony on the ground that his methodology failed to satisfy Federal Rule of Evidence 702, which says: "If scientific, technical, or other specialized knowledge will assist the trier of fact..., a witness qualified as an expert... may testify thereto in the form of an opinion." Granting the motion (and entering summary judgment for the defendants), the District Court acknowledged that it should act as a reliability "gatekeeper" under Daubert v. Merrell Dow Pharmaceuticals. inc U.S L. Ed. 2d 469, 113 S. Ct in which this Court held that Rule 702 imposes a special obligation upon a trial judge to ensure that scientific testimony is not only relevant, but reliable. The court noted that Daubert discussed four factors - testing, peer review, error rates, and "acceptability" in the relevant scientific community - which might prove helpful in determining the reliability of a particular scientific theory or technique, id. at , and found that those factors argued against the reliability of Carlson's [*3] methodology. On the plaintiffs' motion for reconsideration, the court agreed that Daubert should be applied flexibly, that its four factors were simply illustrative, and that other factors could argue in favor of admissibility. However, the court affirmed its earlier order because it found 29

30 insufficient indications of the reliability of Carlson's methodology. In reversing, the Eleventh Circuit held that the District Court had erred as a matter of law in applying Daubert. Believing that Daubert was limited to the scientific context, the court held that the Daubert factors did not apply to Carlson's testimony, which it characterized as skill- or experience-based. Held: 1. The Daubert factors may apply to the testimony of engineers and other experts who are not scientists. Pp (a) The Daubert "gatekeeping" obligation applies not only to "scientific" testimony, but to all expert testimony. Rule 702 does not distinguish between "scientific" knowledge and "technical" or "other specialized" knowledge, but makes clear that any such knowledge might become the subject of expert testimony. It is the Rule's word "knowledge.'' not the words (like [*4] "scientific") that modify that word, that establishes a standard of evidentiary reliability. 509 U.S. at Daubert referred only to "scientific" knowledge because that was the nature of the expertise there at issue. /d. at 590, n. 8. Neither is the evidentiary rationale underlying Daubert's "gatekeeping" detennination limited to "scientific" knowledge. Rules 702 and 703 grant all expert witnesses, not just "scientific" ones, testimonial latitude unavailable to other witnesses on the assumption that the expert's opinion will have a reliable basis in the knowledge and experience of his discipline. /d. at 592. Finally, it would prove difficult, if not impossible, for judges to administer evidentiary rules under which a "gatekeeping" obligation depended upon a distinction between "scientific" knowledge and "technical" or "other specialized" knowledge, since there is no clear line dividing the one from the others and no convincing need to make such distinctions. Pp (b)a trial judge detennining the admissibility of an engineering expert's testimony may consider one or more of the specific Daubert factors. The emphasis on the word "may" reflects [*5] Daubert's description of the Rule 702 inquiry as "a flexible one." 509 U.S. at 594. The Daubert factors do not constitute a definitive checklist or test, id. at 593, and the gatekeeping inquiry must be tied to the particular facts, id. at 591. Those factors may or may not be pertinent in assessing reliability, depending on the nature of the issue, the expert's particular expertise, and the subject of his testimony. Some of those factors may be helpful in evaluating the reliability even of experience-based expert testimony, and the Court of Appeals erred insofar as it ruled those factors out in such cases. In determining whether particular expert testimony is reliable, the trial court 30

31 should consider the specific Daubert factors where they are reasonable measures of reliability. Pp (c) The court of appeals must apply an abuse-of-discretion standard when it reviews the trial court's decision to admit or exclude expert testimony. General Electric Co. v. Joiner. 522 U.S./36, /38-139, 139 L. Ed. 2d 508, 118 S. Ct That standard applies as much to the trial court's decisions about how to determine reliability as to its ultimate conclusion. [*6] Thus, whether Daubert's specific factors are, or are not, reasonable measures of reliability in a particular case is a matter that the law grants the trial judge broad latitude to determine. See id. at 143. The Eleventh Circuit erred insofar as it held to the contrary. P Application of the foregoing standards demonstrates that the District Court's decision not to admit Carlson's expert testimony was lawful. The District Court did not question Carlson's qualifications, but excluded his testimony because it initially doubted his methodology and then found it unreliable after examining the transcript in some detail and considering respondents' defense of it. The doubts that triggered the court's initial inquiry were reasonable, as was the court's ultimate conclusion that Carlson could not reliably determine the cause of the failure of the tire in question. The question was not the reliability of Carlson's methodology in general, but rather whether he could reliably determine the cause of failure of the particular tire at issue. That tire, Carlson conceded, had traveled far enough so that some of the tread had been worn bald, it should have been taken out of service, [*7] it had been repaired (inadequately) for punctures, and it bore some of the very marks that he said indicated, not a defect, but abuse. Moreover, Carlson's own testimony cast considerable doubt upon the reliability of both his theory about the need for at least two signs of abuse and his proposition about the significance of visual inspection in this case. Respondents stress that other tire failure experts, like Carlson, rely on visual and tactile examinations of tires. But there is no indication in the record that other experts in the industry use Carlson's particular approach or that tire experts normally make the very fine distinctions necessary to support his conclusions, nor are there references to articles or papers that validate his approach. Respondents' argument that the District Court too rigidly applied Daubert might have had some validity with respect to the court's initial opinion, but fails because the court, on reconsideration, recognized that the relevant reliability inquiry should be "flexible," and ultimately based its decision upon Carlson's failure to satisfy either Daubert's factors or any other set of reasonable reliability criteria. Pp

32 [*8] /3/ F.3d /433, reversed. JUDGES: BREYER, J., delivered the opinion of the Court, in which REHN QUIST, C. J., and O'CONNOR, SCALIA, KENNEDY, SOUTER, THOMAS, and GINSBURG, JJ., joined, and in which STEVENS, J., joined as to Parts I and II. SCALIA, J., filed a concurring opinion, in which O'CONNOR and THOMAS, JJ., joined. STEVENS, J., filed an opinion concurring in part and dissenting in part. OPINION BY: BREYER OPINION: JUSTICE BREYER delivered the opinion of the Court. In Daubert v. Merrell Dow Pharmaceuticals, Inc., 509 U.S. 579, 125 L. Ed. 2d 469, 1/3 S. Ct ( 1993 ), this Court focused upon the admissibility of scientific expert testimony. It pointed out that such testimony is admissible only if it is both relevant and reliable. And it held that the Federal Rules of Evidence "assign to the trial judge the task of ensuring that an expert's testimony both rests on a reliable foundation and is relevant to the task at hand." /d. at 597. The Court also discussed certain more specific factors, such as testing, peer review, error rates, and "acceptability" in the relevant scientific community, some or all of which might prove helpful in determining the reliability of a particular scientific [*9] "theory or technique." /d. at This case requires us to decide how Daubert applies to the testimony of engineers and other experts who are not scientists. We conclude that Daubert's general holding - setting forth the trial judge's general "gatekeeping" obligation - applies not only to testimony based on "scientific" knowledge, but also to testimony based on "technical" and "other specialized" knowledge. See Fed. Rule Evid We also conclude that a trial court may consider one or more of the more specific factors that Daubert mentioned when doing so will help determine that testimony's reliability. But, as the Court stated in Daubert, the test of reliability is "flexible," and Daubert's list of specific factors neither necessarily nor exclusively applies to all experts or in every case. Rather, the law grants a district court the same broad latitude when it decides how to determine reliability as it enjoys in respect to its ultimate reliability determination. See General Electric Co. v. Joiner, 522 U.S. 136, 143, /39 L. Ed. 2d 508, 118 S. Ct. 512 (1997) (courts of appeals are to apply "abuse of discretion" standard when reviewing district [* 10] court's reliability determination). Applying these standards, we determine that the District Court's decision in this case - not to admit certain expert testimony - was within its discretion and therefore lawful. 32

33 I On July 6, 1993, the right rear tire of a minivan driven by Patrick Carmichael blew out. In the accident that followed, one of the passengers died, and others were severely injured. In October 1993, the Carmichaels brought this diversity suit against the tire's maker and its distributor, whom we refer to collectively as Kumho Tire, claiming that the tire was defective. The plaintiffs rested their case in significant part upon deposition testimony provided by an expert in tire failure analysis, Dennis Carlson, Jr., who intended to testify in support of their conclusion. Carlson's depositions relied upon certain features of tire technology that are not in dispute. A steel-belted radial tire like the Carmichaels' is made up of a "carcass" containing many layers of flexible cords, called "plies," along which (between the cords and the outer tread) are laid steel strips called "belts." Steel wire loops, called "beads," hold the cords together at the plies' bottom edges. [*11] An outer layer, called the "tread," encases the carcass, and the entire tire is bound together in rubber, through the application of heat and various chemicals. See generally, e.g., J. Dixon, Tires, Suspension and Handling (2d ed. 1996). The bead of the tire sits upon a "bead seat," which is part of the wheel assembly. That assembly contains a "rim flange," which extends over the bead and rests against the side of the tire. SeeM. Mavrigian, Performance Wheels & Tires 81,83 (1998) (illustrations). [Graphic omitted; see printed opinion.] A. Markovich, How To Buy and Care For Tires 4 (1994). Carlson's testimony also accepted certain background facts about the tire in question. He assumed that before the blowout the tire had traveled far. (The tire was made in 1988 and had been installed some time before the Carmichaels bought the used minivan in March 1993; the Carmichaels had driven the van approximately 7,000 additional miles in the two months they had owned it.) Carlson noted that the tire's tread depth, which was of an inch when new, App. 242, had been worn down to depths that ranged from 3/32 of an inch along some parts of the tire, to nothing at all along [* 12] others. I d. at 287. He conceded that the tire tread had at least two punctures which had been inadequately repaired. ld. at , 322. Despite the tire's age and history, Carlson concluded that a defect in its manufactu~e or design caused the blow-out. He rested this conclusion in part upon three premises which, for present purposes, we must assume are not in dispute: First, a tire's carcass should stay bound to the inner side of the tread for a 33

34 significant period of time after its tread depth has worn away. Id. at Second, the tread of the tire at issue had separated from its inner steel-belted carcass prior to the accident. ld. at 336. Third, this "separation" caused the blowout. Ibid. Carlson's conclusion that a defect caused the separation, however, rested upon certain other propositions, several of which the defendants strongly dispute. First, Carlson said that if a separation is not caused by a certain kind of tire misuse called "overdeflection" (which consists of underinflating the tire or causing it to carry too much weight, thereby generating heat that can undo the chemical tread/carcass bond), then, ordinarily, its cause is a tire defect. ld. at , [*13] Second, he said that if a tire has been subject to sufficient overdeflection to cause a separation, it should reveal certain physical symptoms. These symptoms include (a) tread wear on the tire's shoulder that is greater than the tread wear along the tire's center, id. at 211; (b) signs of a "bead groove," where the beads have been pushed too hard against the bead seat on the inside of the tire's rim, id. at ; (c) sidewalls of the tire with physical signs of deterioration, such as discoloration, id. at 212; and/or (d) marks on the tire's rim flange, id. at Third, Carlson said that where he does not find at least two of the four physical signs just mentioned (and presumably where there is no reason to suspect a less common cause of separation), he concludes that a manufacturing or design defect caused the separation. ld. at Carlson added that he had inspected the tire in question. He conceded that the tire to a limited degree showed greater wear on the shoulder than in the center, some signs of "bead groove," some discoloration, a few marks on the rim flange, and inadequately filled puncture holes (which can also cause heat that might lead to separation). [* 14] I d. at , , 277, , 308. But, in each instance, he testified that the symptoms were not significant, and he explained why he believed that they did not reveal overdeflection. For example, the extra shoulder wear, he said, appeared primarily on one shoulder, whereas an overdeflected tire would reveal equally abnormal wear on both shoulders. ld. at 277. Carlson concluded that the tire did not bear at least two of the four overdeflection symptoms, nor was there any less obvious cause of separation; and since neither overdeflection nor the punctures caused the blowout, a defect must have done so. Kumho Tire moved the District Court to exclude Carlson's testimony on the ground that his methodology failed Rule 702's reliability requirement. The court agreed with Kumho that it should act as a Daubert-type reliability ''gatekeeper," even though one might consider Carlson's testimony as "technical," rather than "scientific." See Carmichael v. Samyang Tires, Inc., 923 F. Supp. 34

35 1514, (SD Ala. 1996). The court then examined Carlson's methodology in light of the reliability-related factors that Daubert mentioned, such as a theory's testability, whether [* 15] it "has been a subject of peer review or publication," the "known or potential rate of error," and the "degree of acceptance... within the relevant scientific community." 923 F. Supp. at 1520 (citing Daubert. 509 U.S. 579 at ). The District Court found that all those factors argued against the reliability of Carlson's methods, and it granted the motion to exclude the testimony (as well as the defendants' accompanying motion for summary judgment). The plaintiffs, arguing that the court's application of the Daubert factors was too "inflexible," asked for reconsideration. And the Court granted that motion. Carmichael v. Samyang Tires, Inc., Civ. Action No CB-S (SD Ala., June 5, 1996), App. to Pet. for Cert. 1c. After reconsidering the matter, the court agreed with the plaintiffs that Daubert should be applied flexibly, that its four factors were simply illustrative, and that other factors could argue in favor of admissibility. It conceded that there may be widespread acceptance of a "visual-inspection method" for some relevant purposes. But the court found insufficient indications of the reliability of "the component of Carlson's tire failure [* 16] analysis which most concerned the Court. namely, the methodology employed by the expert in analyzing the data obtained in the visual inspection, and the scientific basis, if any, for such an analysis." ld. at 6c. It consequently affirmed its earlier order declaring Carlson's testimony inadmissable and granting the defendants' motion for summary judgment. The Eleventh Circuit reversed. See Carmichael v. Samyang Tire, Inc F.3d 1433 ( 1997). It "reviewed... de novo" the.. district court's legal decision to apply Daubert." 131 F.3d at It noted that "the Supreme Court in Daubert explicitly limited its holding to cover only the 'scientific context,"' adding that "a Daubert analysis" applies only where an expert relies "on the application of scientific principles," rather than.. on skill- or experience-based observation." /d. at It concluded that Carlson's testimony, which it viewed as relying on experience, "falls outside the scope of Daubert," that "the district court erred as a matter of law by applying Daubert in this case," and that the case must be remanded for further (non-daubert-type) consideration under Rule 702. [*17] /d. at Kumho Tire petitioned for certiorari. asking us to determine whether a trial court "may" consider Daubert's specific "factors" when determining the "admissibility of an engineering expert's testimony." Pet. for Cert. i. We 35

36 granted certiorari in light of uncertainty among the lower courts about whether, or how, Daubert applies to expert testimony that might be characterized as based not upon "scientific" knowledge, but rather upon "technical" or "other specialized" knowledge. Fed. Rule Evid. 702; compare, e.g., Watkins v. Telsmith, Inc., 121 F.3d 984, (CAS 1997), with, e.g., Compton v. Subaru of America, Inc., 82 F.3d (CAlO), cert. denied, 519 U.S. 1042, 136 L. Ed. 2d 536, 117 S. Ct. 611 ( 1996). II A In Daubert, this Court held that Federal Rule of Evidence 702 imposes a special obligation upon a trial judge to "ensure that any and all scientific testimony... is not only relevant, but reliable." 509 U.S. at 589. The initial question before us is whether this basic gatekeeping obligation applies only to "scientific" testimony or to all expert testimony. We, like the parties, believe that it applies to all expert [*18] testimony. See Brief for Petitioners 19; Brief for Respondents 17. For one thing, Rule 702 itself says: "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." This language makes no relevant distinction between "scientific" knowledge and "technical" or "other specialized" knowledge. It makes clear that any such knowledge might become the subject of expert testimony. In Daubert, the Court specified that it is the Rule's word "knowledge," not the words (like "scientific") that modify that word, that "establishes a standard of evidentiary reliability." 509 U.S. at Hence, as a matter of language, the Rule applies its reliability standard to all "scientific," "technical," or "other specialized" matters within its scope. We concede that the Court in Daubert referred only to "scientific" knowledge. But as the Court there said, it referred to "scientific" testimony "because that was the nature of the expertise" at issue. [*19] /d. at 590, n. 8. Neither is the evidentiary rationale that underlay the Court's basic Daubert "gatekeeping" determination limited to "scientific" knowledge. Daubert pointed out that Federal Rules 702 and 703 grant expert witnesses testimonial latitude unavailable to other witnesses on the "assumption that the expert's opinion will have a reliable basis in the knowledge and experience of his discipline." /d. at 36

37 592 (pointing out that experts may testify to opinions, including those that are not based on firsthand knowledge or observation). The Rules grant that latitude to all experts, not just to "scientific" ones. Finally, it would prove difficult, if not impossible, for judges to administer evidentiary rules under which a gatekeeping obligation depended upon a distinction between "scientific" knowledge and "technical" or "other specialized" knowledge. There is no clear line that divides the one from the others. Disciplines such as engineering rest upon scientific knowledge. Pure scientific theory itself may depend for its development upon observation and properly engineered machinery. And conceptual efforts to distinguish the two are unlikely to produce clear legal lines [*20] capable of application in particular cases. Cf. Brief for National Academy of Engineering as Amicus Curiae 9 (scientist seeks to understand nature while the engineer seeks nature's modification); Brief for Rubber Manufacturers Association as Amicus Curiae (engineering, as an "applied science," relies on "scientific reasoning and methodology"); Brief for John Allen et al. as Amici Curiae 6 (engineering relies upon "scientific knowledge and methods"). Neither is there a convincing need to make such distinctions. Experts of all kinds tie observations to conclusions through the use of what Judge Learned Hand called "general truths derived from... specialized experience." Hand, Historical and Practical Considerations Regarding Expert Testimony, 15 Harv. L. Rev. 40, 54 (/90/ ). And whether the specific expert testimony focuses upon specialized observations, the specialized translation of those observations into theory, a specialized theory itself, or the application of such a theory in a particular case, the expert's testimony often will rest "upon an experience confessedly foreign in kind to (the jury's) own." Ibid. The trial judge's effort to assure that the [*21] specialized testimony is reliable and relevant can help the jury evaluate that foreign experience, whether the testimony reflects scientific, technical, or other specialized knowledge. We conclude that Daubert's general principles apply to the expert matters described in Rule 702. The Rule, in respect to all such matters, "establishes a standard of evidentiary reliability." 509 U.S. at 590. It "requires a valid... connection to the pertinent inquiry as a precondition to admissibility." /d. at 592. And where such testimony's factual basis, data, principles, methods, or their application are called sufficiently into question, see Part III, infra, the trial judge must determine whether the testimony has "a reliable basis in the knowledge and experience of [the relevant] discipline." 509 U.S. at

38 B The petitioners ask more specifically whether a trial judge determining the "admissibility of an engineering expert's testimony" may consider several more specific factors that Daubert said might "bear on" a judge's gate-keeping determination. These factors include: - Whether a "theory or technique... can be (and has been) tested"; - Whether it "has [*22] been subjected to peer review and publication"; - Whether, in respect to a particular technique, there is a high "known or potential rate of error" and whether there are "standards controlling the technique's operation"; and - Whether the theory or technique enjoys "general acceptance" within a "relevant scientific community." 509 U.S. at Emphasizing the word "may" in the question, we answer that question yes. Engineering testimony rests upon scientific foundations, the reliability of which will be at issue in some cases. See, e.g., Brief for Stephen Bobo et al. as Amici Curiae 23 (stressing the scientific bases of engineering disciplines). In other cases, the relevant reliability concerns may focus upon personal knowledge or experience. As the Solicitor General points out, there are many different kinds of experts, and many different kinds of expertise. See Brief for United States as Amicus Curiae 18-19, and n. 5 (citing cases involving experts in drug terms, handwriting analysis, criminal modus operandi, land valuation, agricultural practices, railroad procedures, attorney's fee valuation, and others). Our emphasis on the word "may" thus reflects [*23] Daubert's description of the Rule 702 inquiry as "a flexible one." 509 U.S. at 594. Daubert makes clear that the factors it mentions do not constitute a "definitive checklist or test." /d. at 593. And Daubert adds that the gatekeeping inquiry must be '"tied to the facts"' of a particular "case." /d. at 591 (quoting United States v. Downing, 753 F.2d / (CA3 1985)). We agree with the Solicitor General that "the factors identified in Daubert may or may not be pertinent in assessing reliability, depending on the nature of the issue, the expert's particular expertise, and the subject of his testimony." Brief for United States as Amicus Curiae 19. The conclusion, in our view, is that we can neither rule out, nor rule in, for all cases and for all time the applicability of the factors mentioned in Daubert, nor can we now do so for subsets of cases categorized by category of expert or by kind of evidence. Too much depends upon the particular circumstances of the particular case at issue. 38

39 Daubert itself is not to the contrary. It made clear that its list of factors was meant to be helpful, not definitive. Indeed, those factors do not all necessarily [*24] apply even in every instance in which the reliability of scientific testimony is challenged. It might not be surprising in a particular case, for example, that a claim made by a scientific witness has never been the subject of peer review, for the particular application at issue may never previously have interested any scientist. Nor, on the other hand, does the presence of Daubert's general acceptance factor help show that an expert's testimony is reliable where the discipline itself lacks reliability, as, for example, do theories grounded in any so-called generally accepted principles of astrology or necromancy. At the same time, and contrary to the Court of Appeals' view, some of Daubert's questions can help to evaluate the reliability even of experiencebased testimony. In certain cases, it will be appropriate for the trial judge to ask, for example, how often an engineering expert's experience-based methodology has produced erroneous results, or whether such a method is generally accepted in the relevant engineering community. Likewise, it will at times be useful to ask even of a witness whose expertise is based purely on experience, say, a perfume tester able to distinguish [*25] among 140 odors at a sniff, whether his preparation is of a kind that others in the field would recognize as acceptable. We must therefore disagree with the Eleventh Circuit's holding that a trial judge may ask questions of the sort Daubert mentioned only where an expert "relies on the application of scientific principles," but not where an expert relies "on skill- or experience-based observation." 131 F.3d at We do not believe that Rule 702 creates a schematism that segregates expertise by type while mapping certain kinds of questions to certain kinds of experts. Life and the legal cases that it generates are too complex to warrant so definitive a match. To say this is not to deny the importance of Daubert's gatekeeping requirement. The objective of that requirement is to ensure the reliability and relevancy of expert testimony. It is to make certain that an expert, whether basing testimony upon professional studies or personal experience, employs in the courtroom the same level of intellectual rigor that characterizes the practice of an expert in the relevant field. Nor do we deny that, as stated in Daubert, the particular questions that it mentioned will often [*26] be appropriate for use in determining the reliability of challenged expert testimony. Rather, we conclude that the trial judge must have considerable leeway in deciding in a particular case how to go about determining whether particular expert testimony is reliable. That is to say, a trial court should consider the specific factors identified in Daubert where they are reasonable measures of the reliability of expert testimony. 39

40 c The trial court must have the same kind of latitude in deciding how to test an expert's reliability, and to decide whether or when special briefing or other proceedings are needed to investigate reliability, as it enjoys when it decides whether that expert's relevant testimony is reliable. Our opinion in Joiner makes clear that a court of appeals is to apply an abuse-of-discretion standard when it "reviews a trial court's decision to admit or exclude expert testimony." 522 U.S. at That standard applies as much to the trial court's decisions about how to determine reliability as to its ultimate conclusion. Otherwise, the trial judge would lack the discretionary authority needed both to avoid unnecessary "reliability" proceedings in [*27] ordinary cases where the reliability of an expert's methods is properly taken for granted, and to require appropriate proceedings in the less usual or more complex cases where cause for questioning the expert's reliability arises. Indeed, the Rules seek to avoid "unjustifiable expense and delay" as part of their search for "truth" and the "just determination" of proceedings. Fed. Rule Evid Thus, whether Daubert's specific factors are, or are not, reasonable measures of reliability in a particular case is a matter that the law grants the trial judge broad latitude to determine. See Joiner, supra, at 143. And the Eleventh Circuit erred insofar as it held to the contrary. III We further explain the way in which a trial judge "may" consider Daubert's factors by applying these considerations to the case at hand, a matter that has been briefed exhaustively by the parties and their 19 amici. The District Court did not doubt Carlson's qualifications, which included a masters degree in mechanical engineering, 10 years' work at Michelin America, Inc., and testimony as a tire failure consultant in other tort cases. Rather, it excluded the testimony because, despite [*28] those qualifications, it initially doubted, and then found unreliable, "the methodology employed by the expert in analyzing the data obtained in the visual inspection, and the scientific basis, if any, for such an analysis." Civ. Action No CB-S (SD Ala., June 5, 1996), App. to Pet. for Cert. 6c. After examining the transcript in "some detail," 923 F. Supp. at , n. 4, and after considering respondents' defense of Carlson's methodology, the District Court determined that Carlson's testimony was not reliable. It fell outside the range where experts might reasonably differ, and where the jury must decide among the conflicting views of different experts, even though the evidence is "shaky." Daubert, 509 U.S. at 596. In our view, the doubts that triggered the District Court's initial inquiry here were reasonable, as was the court's ultimate conclusion. For one thing, and contrary to respondents' suggestion, the specific issue before the court was not the reasonableness in general of a tire expert's use of a visual and tactile inspection to determine 40

41 whether overdeflection had caused the tire's tread to separate from its steelbelted carcass. Rather, it was the reasonableness [*29] of using such an approach, along with Carlson's particular method of analyzing the data thereby obtained, to draw a conclusion regarding the particular matter to which the expert testimony was directly relevant. That matter concerned the likelihood that a defect in the tire at issue caused its tread to separate from its carcass. The tire in question, the expert conceded, had traveled far enough so that some of the tread had been worn bald; it should have been taken out of service; it had been repaired (inadequately) for punctures; and it bore some of the very marks that the expert said indicated, not a defect, but abuse through overdeflection. See supra, at 3-5; App The relevant issue was whether the expert could reliably determine the cause of this tire's separation. Nor was the basis for Carlson's conclusion simply the general theory that, in the absence of evidence of abuse, a defect will normally have caused a tire's separation. Rather, the expert employed a more specific theory to establish the existence (or absence) of such abuse. Carlson testified precisely that in the absence of at least two of four signs of abuse (proportionately greater tread wear [*30] on the shoulder; signs of grooves caused by the beads; discolored sidewalls; marks on the rim flange) he concludes that a defect caused the separation. And his analysis depended upon acceptance of a further implicit proposition, namely, that his visual and tactile inspection could determine that the tire before him had not been abused despite some evidence of the presence of the very signs for which he looked (and two punctures). For another thing, the transcripts of Carlson's depositions support both the trial court's initial uncertainty and its final conclusion. Those transcripts cast considerable doubt upon the reliability of both the explicit theory (about the need for two signs of abuse) and the implicit proposition (about the significance of visual inspection in this case). Among other things, the expert could not say whether the tire had traveled more than 10, or 20, or 30, or 40, or 50 thousand miles, adding that 6,000 miles was "about how far" he could "say with any certainty." ld. at 265. The court could reasonably have wondered about the reliability of a method of visual and tactile inspection sufficiently precise to ascertain with some certainty the abuse-related significance [*31] of minute shoulder/center relative tread wear differences, but insufficiently precise to tell "with any certainty" from the tread wear whether a tire had traveled less than 10,000 or more than 50,000 miles. And these concerns might have been augmented by Carlson's repeated reliance on the "subjectiveness" of his mode of analysis in response to questions seeking specific information regarding how he could differentiate between a tire that actually had been overdeflected and a tire that merely looked as though it had been. Id. at 222, , They would have been further augmented by the fact that Carlson said he had inspected the tire itself for the first time the morning of his first deposition, and 41

42 then only for a few hours. (His initial conclusions were based on photographs.) ld. at 180. Moreover, prior to his first deposition, Carlson had issued a signed report in which he concluded that the tire had "not been... overloaded or underinflated," not because of the absence of "two of four" signs of abuse, but simply because "the rim flange impressions... were normal." ld. at That report also said that the "tread depth remaining was 3/32 inch," id. at 336, though [*32] the opposing expert's (apparently undisputed) measurements indicate that the tread depth taken at various positions around the tire actually ranged from.5/32 of an inch to 4/32 of an inch, with the tire apparently showing greater wear along both shoulders than along the center, id. at Further, in respect to one sign of abuse, bead grooving, the expert seemed to deny the sufficiency of his own simple visual-inspection methodology. He testified that most tires have some bead groove pattern, that where there is reason to suspect an abnormal bead groove he would ideally "look at a lot of [similar] tires" to know the grooving's significance, and that he had not looked at many tires similar to the one at issue. ld. at , 214, 217. Finally, the court, after looking for a defense of Carlson's methodology as applied in these circumstances, found no convincing defense. Rather, it found (1) that "none" of the Daubert factors, including that of "general acceptance" in the relevant expert community, indicated that Carlson's testimony was reliable, 923 F. Supp. at 1521; (2) that its own analysis "revealed no countervailing factors operating in favor of admissibility which [*33] could outweigh those identified in Daubert," App. to Pet. for Cert. 4c; and (3) that the "parties identified no such factors in their briefs," ibid. For these three reasons taken together, it concluded that Carlson's testimony was unreliable. Respondents now argue to us, as they did to the District Court, that a method of tire failure analysis that employs a visual/tactile inspection is a reliable method, and they point both to its use by other experts and to Carlson's long experience working for Michelin as sufficient indication that that is so. But no one denies that an expert might draw a conclusion from a set of observations based on extensive and specialized experience. Nor does anyone deny that, as a general matter, tire abuse may often be identified by qualified experts through visual or tactile inspection of the tire. See Affidavit of H. R. Baumgardner 1-2, cited in Brief for National Academy of Forensic Engineers as Amici Curiae 16 (Tire engineers rely on visual examination and process of elimination to analyze experimental test tires). As we said before, supra, at 14, the question before the trial court was specific, not general. The trial court had to [*34] decide whether this particular expert had sufficient specialized knowledge to assist the 42

43 jurors "in deciding the particular issues in the case." 4 J. McLaughlin, Weinstein's Federal Evidence P702.05ll], p (2d ed. 1998); see also Advisory Committee's Note on Proposed Fed. Rule Evid. 702, Preliminary Draft of Proposed Amendments to the Federal Rules of Civil Procedure and Evidence: Request for Comment 126 (1998) (stressing that district courts must "scrutinize" whether the "principles and methods" employed by an expert "have been properly applied to the facts of the case"). The particular issue in this case concerned the use of Carlson's two-factor test and his related use of visual/tactile inspection to draw conclusions on the basis of what seemed small observational differences. We have found no indication in the record that other experts in the industry use Carlson's two-factor test or that tire experts such as Carlson normally make the very fine distinctions about, say, the symmetry of comparatively greater shoulder tread wear that were necessary, on Carlson's own theory, to support his conclusions. Nor, despite the prevalence of tire testing, does anyone refer to any [*35] articles or papers that validate Carlson's approach. Compare Bobo, Tire Flaws and Separations, in Mechanics of Pneumatic Tires (S. Clark ed. 1981); C. Schnuth et al., Compression Grooving and Rim Flange Abrasion as Indicators of Over Deflected Operating Conditions in Tires, presented to Rubber Division of the American Chemical Society, Oct , 1997; J. Walter & R. Kiminecz, Bead Contact Pressure Measurements at the Tire-Rim Interface, presented to Society of Automotive Engineers, Feb , Indeed, no one has argued that Carlson himself, were he still working for Michelin, would have concluded in a report to his employer that a similar tire was similarly defective on grounds identical to those upon which he rested his conclusion here. Of course, Carlson himself claimed that his method was accurate, but, as we pointed out in Joiner, "nothing in either Daubert or the Federal Rules of Evidence requires a district court to admit opinion evidence that is connected to existing data only by the ipse dixit of the expert." 522 U.S. at 146. Respondents additionally argue that the District Court too rigidly applied Daubert's criteria. They read its opinion [*36] to hold that a failure to satisfy any one of those criteria automatically renders expert testimony inadmissible. The District Court's initial opinion might have been vulnerable to a form of this argument. There, the court, after rejecting respondents' claim that Carlson's testimony was "exempted from Daubert-style scrutiny" because it was "technical analysis" rather than.. scientific evidence," simply added that "none of the four admissibility criteria outlined by the Daubert court are satisfied." 923 F. Supp. at Subsequently, however, the court granted respondents' motion for reconsideration. It then explicitly recognized that the relevant reliability inquiry "should be 'flexible,"' that its '"overarching subject [should be]... validity' and reliability," and that "Daubert was intended neither to be exhaustive nor to 43

44 apply in every case." App. to Pet. for Cert. 4c (quoting Daubert, 509 U.S. at ). And the court ultimately based its decision upon Carlson's failure to satisfy either Daubert's factors or any other set of reasonable reliability criteria. In light of the record as developed by the parties, that conclusion was within the District [*37] Court's lawful discretion. In sum, Rule 702 grants the district judge the discretionary authority, reviewable for its abuse, to determine reliability in light of the particular facts and circumstances of the particular case. The District Court did not abuse its discretionary authority in this case. Hence, the judgment of the Court of Appeals is Reversed. CONCURBY: SCALIA CONCUR: JUSTICE SCALIA, with whom JUSTICE O'CONNOR and JUS TICE THOMAS join, concurring. I join the opinion of the Court, which makes clear that the discretion it endorses- trial-court discretion in choosing the manner of testing expert reliability- is not discretion to abandon the gatekeeping function. I think it worth adding that it is not discretion to perform the function inadequately. Rather, it is discretion to choose among reasonable means of excluding expertise that is fausse and science that is junky. Though, as the Court makes clear today, the Daubert factors are not holy writ, in a particular case the failure to apply one or another of them may be unreasonable, and hence an abuse of discretion. DISSENTBY: STEVENS (In Part) DISSENT: JUSTICE STEVENS, concurring in part and dissenting [*38] in part. The only question that we granted certiorari to decide is whether a trial judge "may... consider the four factors set out by this Court in Daubert v. Merrell Dow Pharmaceuticals. Inc., 509 U.S. 579, 125 L. Ed. 2d 469, 113 S. Ct (1993). in a Rule 702 analysis of admissibility of an engineering expert's testimony." Pet. for Cert. i. That question is fully and correctly answered in Parts I and II of the Court's opinion, which I join. Part III answers the quite different question whether the trial judge abused his discretion when he excluded the testimony of Dennis Carlson. Because a proper answer to that question requires a study of the record that can be performed more efficiently by the Court of Appeals than by the nine Members of 44

45 this Court, I would remand the case to the Eleventh Circuit to perform that task. There are, of course, exceptions to most rules, but I firmly believe that it is neither fair to litigants nor good practice for this Court to reach out to decide questions not raised by the certiorari petition. See General Electric Co. v. Joiner, 522 U.S L. Ed. 2d S. Ct. 512 (1997) (STEVENS, J., concurring in part [*39] and dissenting in part). Accordingly, while I do not feel qualified to disagree with the well-reasoned factual analysis in Part III of the Court's opinion, I do not join that Part, and I respectfully dissent from the Court's disposition of the case. 45

46 Kumho Tire- An Update by, David V. Scott 1 Introduction There are very few experts who have not been profoundly affected by the U.S. Supreme Courts decisions in Dauber{!, Joiner ' and Kumho Tire 4 Many, including myself, have analyzed the holding in Kumlw and the effect that decision should have on the admissibility of engineering testimony. More important than prognostication is the actual application of the doctrine. Between the time Kumho was decided, March 23, 1999 and January 2, 2001 over 650 reported cases have cited it. Generally the predicted consequences of Kwnho have held true, but it is an amorphous doctrine that can precipitate diverse results. Certain aspects of the opinion will remain constant. First, the trial judge in federal court and most state courts has the obligation to insure that all expert testimony is reliable in all aspects. This obligation has been held to apply even if the opposing party does not object to the testimony. Secondly, the judges decision will not be set aside absent an abuse of discretion. Thirdly, the "Daubert factors" are not to be applied to every expert in every case and fourthly, the context in which the testimony is given that will control the analysis of that testimony. It is this last aspect of Kumlw that will likely have the greatest impact on experts generally and engineering experts specifically. This is good news for engineers with a high level of "hands on" experience in the field in which they will be offering evidence and likely bad news for engineers who do not. I. THE FEDERAL JUDICIAL CENTER'S REFERENCE MANUAL ON SCIENTIFIC EVIDENCE, SECOND EDITION. Perhaps the most significant recent development since Kumho was decided is the Second Edition of the Federal Judicial Center's Reference Manual on Scientific Evidence released in late It is significant because this will be the primary reference source for federal judges ruling on the admissibility of expert testimony. Fortunately, the manual correctly interprets two very important aspects of Kwnho. 47

47 A. The Role of the "Daubert Factors." A problem with Kumho Tire is that many judges do not take their analysis past the conclusion that a trial judge's "gatekeeper" role extended to all expert testimony. The Court in Kumho made it as clear as it could that the "Daubert factors 5 " did not constitute a check list to be given wooden application to all expert testimony in all cases. The petitioners ask more specifically whether a trial judge determining the "admissibility of an engineering expert's testimony" may consider several more specific factors that Daubert said might "bear on" a judge's gate-keeping determination. * * * Emphasizing the word "may" in the question, we answer that question yes. * * * Our emphasis on the word "may" thus reflects Daubert's description of the Rule 702 inquiry as "a flexible one." 509 U.S. at 594. Daubert makes clear that the factors it mentions do not constitute a "definitive checklist or test." /d. at 593. And Daubert adds that the gatekeeping inquiry must be '"tied to the facts"' of a particular "case." 6 * * * Daubert itself is not to the contrary. It made clear that its list of factors was meant to be helpful, not definitive. Indeed, those factors do not all necessarily apply even in every instance in which the reliability of scientific testimony is challenged. 7 (Emphasis Supplied) * * * "... the Court makes clear today, the Daubert factors are not holy writ 8." In spite of this many courts continue to measure testimony by them. Fortunately, the Manual makes it quite clear that their role is limited to those situations were they truly apply: The defendant had stated at oral argument that the factors discussed in Daubert were "always relevant." Justice Bryer's opinion rejects this notion categorically. * * * 48

48 Determining which factors are indicative if reliable in a particular case cannot be accomplished solely by categorical a priori characterizations about the particular field in question. The court explained: "Engineering testimony may rest upon scientific foundations, the reliability of which will be at issue in some cases...in other cases, the relevant reliability concerns may focus upon personal knowledge or experience."., (Emphasis supplied) In its analysis of the trilogy of Daubert. Joiner and Kumho the Manual addresses the impact Kumho has on the two prior decisions. Again, the first point made is Kumho 's impact on the Daubert factors." Certainly the Court's opinion does not support those who construed Daubert as creating a four-factor test for scientific evidence, or those who thought that the court might in subsequent cases articulate classification schemes for other fields of expertise. * * * It appears less interested in a taxonomy of expertise and more concerned about direction judges to concentrate on.. the particular circumstances of the particular case at issue." This flexible, non doctrinaire approach is faithful to the intention of the drafters of the Federal Rules of Evidence, who viewed Article VII as setting forth flexible standards for courts to apply rather than rigid rules.'" (Emphasis supplied) Unfortunately, many writers have replaced the.. four-factor" test with another check list which contains as many as thirty.. factors." This is another reason this Manual is important for the expert and his or her client. The Manual does not attempt to replace one rigid group of "factors" with another. B. The Role Real World Experience Plays in the Admissibility Engineering Testimony. A concern engineers generally and NAFE specifically was that pre-kumho decisions were not giving proper weight to the role experience plays in engineering analysis. Clearly Kumho addressed this and the authors of the Manual carried it forward. In Kwnlzo, the Court contemplated that there will be witnesses whose expertise is based purely on experience," and although it suggested that Daubert's questions may be helpful in evaluating experience-based testimony, it did not single out testability as the preeminent factor of concern as it did in Daubert

49 One aspect of Kumho that was applied to limit admissibility can and should be utilized by engineering experts to enhance the "reliability, of their testimony. This is referred to in the manual as "intellectual rigor." It is referring to the following passage in Kumho: The objective of that requirement is to ensure the reliability and relevancy of expert testimony. It is to make certain that an expert, whether basing testimony upon professional studies or personal experience, employs in the courtroom the same level of intellectual rigor that characterizes the practice of an expert in the relevant field. 12 (Emphasis supplied) What this means is that if all engineers in a particular field handle a problem in the specific manner, or use a particular methodology, that practice or methodology can be a benchmark for both the admissibility and exclusion of testimony. It is not enough, therefore, under the "intellectual rigor, test for experts to venture hunches that they would never express or act upon in their everyday working lives. Experts must show that their conclusions were reached by methods that are consistent with how their colleagues in the relevant field or discipline would proceed to establish a proposition were they presented with the same facts and issues. 13 What this means, simply put, that there should be no difference between the way an expert reaches an opinion in court and the actual practice of his profession. The caveat here is that the expert who is offering opinion testimony based experience or following procedures utilized by a particular industry or profession, must document that the industry does, in fact, follow the procedure or methodology proposed and that he or she has followed them. Never lose sight of the objective, namely to demonstrate the "reliability" of the opinion. The mere fact that an engineer follows procedures or uses a methodology in court in a manner consistent with every day practice will not guarantee admissibility if those practices themselves are sloppy and therefore "unreliable,. C. Using the Manual to Help the Court Understand the True Meaning of the "Daubert Factors." One of the sections in the Manual is entitled "How Science Works." It is an academic discussion of the history of the scientific method and is a section engineers may have a tendency to pass over. Don't. It is not, per se, important to an engineers testimony, but this section helps considerably to demonstrate the 50

50 proposition that the "Daubert factors" have special meaning not applicable to most engineering testimony. The Daubert factors were created to deal with a specific situation, namely, determining causation in a case involving the cutting edge of epidemiology. The language in the factors are clearly relevant to that field specifically and cutting edge science generally. They have special meaning. These criteria can have little or nothing to do with the reliability of an engineers opinions. Peer review is integral of the scientific process. The Manual describes science as an adversary process. The author of this section of the manual describes it as crucial that every idea receive the most vigorous possible advocacy, just in case it might be right." ~ An engineering problem needs a solution, not theory. "In the competition among ideas, the institution of peer review plays a central role." t:' " Peer review works superbly to separate valid science from nonsense or, in Kuhnian terms, to ensure that the current paradigm has been respected." Jh Peer review does not fulfill the same role in engineering. There are engineering publications that are.. peer reviewed", but engineers, when they write, are sharing actual experiences. Most practicing engineers do not write journal articles. The fact that some do is not necessarily an indicator that their testimony is more reliable than those that do not. Even in science, peer review does not insure reliability. "It [peer review] works very poorly in catching cheating or fraud, because all scientists are socialized to believe that even their bitterest competitor is rigorously honest in the reporting of scientific results, making it easy to fool a referee with purposeful dishonesty if one wants to." There are published peer reviewed engineering articles that reach questionable conclusions. "Known error rates" is, again, an important tool in cutting edge research. It does not have the meaning given to it by most courts. "Error" in this context does not refer to "mistakes", scientists do not report mistakes, it refers to an assignment of a confidence level in a reported result. n Most of engineering practice is applying known engineering principles to a particular project. In most cases, cutting edge technology is not used. If the scientific process attempts to always probe the edge, the engineering process tries to stay safely short of the edge. In products liability design cases the engineer, in most jurisdictions, must have a "reasonable alternative design." This design has to be feasible and practical. There is no place for designs that might be right, or designs that "only" have a certain error rate. 51

51 D. Locating the Manual and Other Publications From the Federal Judicial Center. Every forensic engineer should obtain at least portions of the Manual. It can be found on the internet at The website for the Federal Judicial Center is The total manual is over 650 pages long. The Manual can be down loaded in sections. The sections that should be down loaded are the preface through the section entitled "How Science Works." The section entitled "Management of Expert Evidence" should probably be down loaded also. It describes the Center's recommendation to the trial judge as to how, procedurally, to address admissibility issues. It is a process the expert will not be involved in unless there is a hearing. It is still a process that will affect the expert profoundly and should be understood by him or her. Several sections in the Manual address specific types of expert testimony. "Reference Guide on Engineering Practice and Methods" is not going to provide much useful information for either engineers or lawyers, but it still must be reviewed. Again, this is what a federal judge or the judge's law clerk will be reviewing when passing on the admissibility of engineering testimony. Another short publication (7 pages), available from the Center that every expert should read is "Expert Testimony in Federal Civil Trials, A Preliminary Analysis". It reports a survey taken of federal judges regarding their experience with expert testimony. It also tracks a similar study made in 1991 and compares the results. It demonstrates, among other things, that judges have a concern about what they perceive is bias in the experts testimony. It may be down loaded also. The Reference Manual on Scientific Evidence may also be purchased from Matthew Bender/LEXIS Law Publishing for $ Contact Sandy Panten, (800) Ext She is in its East Coast facility. She is in from 11:00 a.m. to 7:00p.m., Eastern Time and 8:00a.m. to 4:00p.m. Pacific Time. II. CHANGES IN THE FEDERAL RULES OF EVIDENCE. The issue in Daubert was whether or not the adoption of the Federal Rules of Evidence (FRE)had superceded the Frye 18 "general acceptance" test for scientific evidence. The Daubert Court held it did. 19 Now FRE 702 is being amended "in response to Daubert. 20 " The new rule with the changes italicized is: 52

52 Rule 702. Testimony by Experts If scientific, technical, or other specialized knowledge will assist the trier of fact to understand the evidence or to detennine a fact in issue, a witness qualified as an expert by knowledge, skill, experience, training or education, may testify thereto in the fonn of an opinion or otherwise if ( 1) the testimony is based upon sufficient facts or data, (2)the testimony is the product of reliable principles and methods, and ( 3) the witness has applied the principles and methods reliably to the facts of the case. 11 There is nothing in these changes that was not already present in Kumho. An honest reading of Daubert leads only to the conclusion that, in that case, the Supreme Court was attempting to expand admissibility not restrict it. The Court in Daubert still had confidence in the systems ability to deal with shaky testimony without judicial interference: Vigorous cross-examination, presentation of contrary evidence, and careful instruction on the burden of proof are the traditional and appropriate means of attacking shaky but admissible evidence. 12 These changes in the rules make it clear that the trial judge has authority, and probably the obligation, to determine the reliability of all aspects of an experts opinion. Another change that impacts expert testimony, but not, directly, its admissibility occur in FRE 703. The new rule with changes italicized is as follows: Rule 703. Bases of Opinion Testimony by Experts 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 or at or before the hearing. If of a type reasonably relied upon by experts in the particular field in fonning opinions or inferences upon the subject, the facts or data need not be admissible in evidence in order for the opinion or inference to be admitted. Facts or data that are otherwise inadmissible shall not be disclosed to the jury by the proponent of the opinion or inference unless the court determines that their probative value in assisting the jury to evaluate the expert's opinion substantially outweighs their prejudicial effect. 2 \ These changes were effective as of December 1,

53 III. DEALING WITH KUMHO. As noted previously there have been over 650 cases citing Kumho since it was decided less than two years ago. Kumho has profoundly effected the admissibility of all expert testimony. In some instances the change has been good, however the number of experts that have been excluded is continuing to go up. There is a feeling by some experts that they become more Daubert or Kumho "proof' each time they get past a challenge. This is not the case. Each opinion in each case can be challenged on the basis of the methodology used or the factual foundation of the opinion. In Kumho the Court had no problems with the excluded experts qualifications or his methodology. It was concerned with the manner in which he reached his conclusions in that particular case. It is more important than ever for an expert to have an understanding of guidelines he or she needs to follow to avoid running afoul of Kumho and have all or part of their evidence stricken. There is enough uncertainty out there that all an expert can do is to have a good understanding of the basic rules and document his or her opinion as well as they can. Make no mistake about it, when you sign on to make an analysis and offer your opinion, you should plan for it to be challenged. Also please be aware that your best efforts might not be enough. A. The Importance of the Expert's Report. The experts report is of critical importance now. In the federal system it will likely control both the parameters and admissibility of the testimony. In state court in jurisdictions following Daubert and Kumho a report that complies with all aspects of Rule 26(a) of the Federal Rules is the best vehicle an expert has to insure that his or her opinion will not be excluded. From a practical standpoint, the expert should assume that all states follow Daubert et al. Most do to some degree or another. If the expert's report carefully documents the expert's conclusions and methodology and the reliability of the methodology used and conclusions reached, the expert has done all he or she can to assure that they will make it past the "gatekeeper." Experts and their clients must also be aware that just making it past the "gatekeeper" is not enough if a reviewing court decides the "gatekeeper" did not do his or her job. After it decided Kumho the U. S. Supreme Court held that if a reviewing court determined that a plaintiff's experts' testimony was not "reliable" and should have been excluded the reviewing court could set aside the verdict and enter judgment for the defendantf 4 When this occurs, there are likely to be repercussions. The best way experts can protect themselves is by providing a well documented report in the first instance. 54

54 While it should be clear that the Daubert "factors" are no longer holy wrif! 5 " they still must be addressed if only to make it clear that they do not apply. When the Supreme Court decided Daubert it gave an excellent ''check list" for judges to use when analyzing the admissibility of expert testimony in cutting edge science. It has been criticized for its failure to provide more guidance to the trial judge when assessing the reliability of experts in other areas.~" Professor Imwinkelried, a former chair of the Evidence Section of the American Association of Law Schools and the author of one of the amicus briefs filed on behalf of the respondents in Kumho, made an attempt to fill that void. 2 i The professor has a two factor test that does seem to go to the heart of Rule 702 and is consistent with the general guidelines laid down in Kumho. One factor is an empirical study showing that practitioners of the nonscientific expertise in question can resolve factual questions more reliably than laypersons. The second is a showing of extensive third party reliance on this type of nonscientific opinion-reliance by competent persons other than the practitioners of the nonscientific discipline?~ The example given is a case involving a handwriting expert in a criminal case. The Judge allowed the testimony despite considerable evidence from the defendant's experts that the analysis was unreliable. The Judge allowed the testimony based on a study that merely showed that handwriting experts were wrong 6.5 percent of the time. but that lay people attempting the same analysis were wrong 38.3% of the time. It is difficult to imagine a better example of the true purpose of a Judge's gate keeper's role. The study demonstrates that the expert can perform the task accurately in the vast majority of cases and that the expert's validity rate is markedly higher than that of the typical layperson-the type of person sitting on the bench and in the jury box at trial. When this type of study is available, the field is no longer a mere self-validating discipline. The trial judge has a much more solid basis for his or her reliability finding than the word of the self-proclaimed experts who practice the discipline? 1 There may or may not be a single study as in the example used by the Professor, but an expert can address the heart of this factor by showing why their analysis is has much greater validity than a lay person's. This "factor" is correct in that the Professor has correctly analyzed the FRE 702, but one that I would be cautious about putting too much stock in. 55

55 His second "factor" is one that could have real practical value. It is a systematic method of documenting the "intellectual rigor" test. He calls it "proof of extensive third party" reliance which "can take the form of a showing that a large, competent group other than the practitioners of the nonscientific technique generally relies on the technique." 311 As will be seen, this factor is the one that should be the easiest to document and of particular importance to engineers. The elements of the Professor's second factor: 1. The proponent must establish that a group other than the practitioners of the discipline rely on the technique. 2. Whether the group consists of experts or lay person, its members must be competent to determine whether the technique is valid. 3. The Group must be large in number. 4. The showing should take the form of real world reliance on the technique rather than mere subject belief in the technique:' 1 However it is accomplished, the primary obligation is to demonstrate that: (1) your testimony is based upon sufficient facts or data, (2)your testimony is the product of reliable principles and methods, and (3) you applied the principles and methods reliably to the facts of the case. Do not try to stretch your testimony to fit under one of the harbingers of Daubert! As will be seen the primary consideration is the reliability of all aspects of your opinion. Taking the Daubert factors too literally can create as many problems as it solves. Don Slavik, a lawyer/engineer has analogized a proper report in the era of Daubert!Kumho to a master's thesis. This is not too extreme! An expert's report is the one place were he or she can insure all information relative to his or her opinion is documented. A complete and fully documented report protects both the expert and the expert's client. Some federal courts are not going to let an expert testify to anything that is not included in the report, even if he or she is deposed! B. The "Daubert Factors" Out of Control. 1. Peer Review. An excellent example of what happens when a trial judge takes one or more of the factors too literally is Smith v. Ford Motor Company:' 2 The trial judge excluded the plaintiffs because he: "... concluded that neither witness 1) qualified as an expert in the design or manufacture of power steering gear boxes; 2) had submitted his work 56

56 for peer review; or 3) had an opinion as to whether there was a design or manufacturing defect in the steering mechanism:' ' (Emphasis supplied) The Court of Appeals observed that both experts had extensive "practical" experience in the specific aspects auto industry and in the specific areas in which they were offering testimony. In addressing the issue regarding the lack of peer reviewed publications the Appellate Court analyzed the their testimony using the factors practicing engineers would want them to: In Kumho, the Court made clear that the reliability test under Rule 702 is an individualized test whose relevant factors will depend on the type of expertise at issue in a given case. See Kumho, 526 U.S. at 150 (stating that in some cases "the relevant reliability concerns may focus upon personal knowledge or experience... There are many different kinds of experts, and many different kinds of expertise.") (citations omitted). While the district court noted that neither expert had had his work published in a peer reviewed journal, the district court did not indicate whether publication is typical for the type of methodology these experts purported to employ. The district court merely recited the failure of the experts to publish and concluded that their testimony was unreliable. However, as noted above, lack of peer review will rarely, if ever, be the single dispositive factor that determines the reliability of expert testimony. Without a further explanation of the connection between lack of publication and reliability in this case, we cannot determine the extent to which this factor bears on the reliability of the methodologies used by plaintiff's proposed experts. For example, if Muszar was merely applying well-established engineering techniques to the particular materials at issue in this case, then his failure to submit those techniques to peer review establishes nothing about their reliability. Similarly, if Cassassa' s accident reconstruction methodology is based on his extensive practical experience in this area, rather than novel methodology subject to publication, his failure to publish does not cast doubt on the reliability of his analytical technique. However, other factors not considered by the district court, such as the general acceptance of the techniques in the relevant engineering and accident analysis communities or the extent of the experts' practical experience performing those techniques, may bear on the reliability of the proposed evidence. On the record before us, we conclude that the district court erred by relying on a single, potentially irrelevant, criterion to determine that plaintiff's proposed experts based their conclusions on methodologies that are not sufficiently reliable to satisfy the requirements of Rule 702.-' 4 (Emphasis supplied) 57

57 Again, while this case makes it clear that the "factors" are not a litmus test, but it is important to we aware of the "factors" and address why they do or do not apply to a given instance 2. The Importance of Actual Experience in the Field. As indicated initially, one clear result of Kumho is that experience counts. The court's ruling in Smith v. Rasmussen 35 is an excellent example of the extent to which Kumho changed the rules for experts. The issue in that case was whether or not a sex change operation should be covered under a health insurance policy. The plaintiff's doctor was a psychiatrist who had treated over a thousand individuals with some form of "gender identity disorder" contended that it was a necessary treatment for this individual. The defendant's expert was a general psychiatrist who, based on a review of the literature, was prepared to testify that the procedure was controversial and not a "curative procedure." Prior to Kumho both opinions would be admitted with the defendant's experts lack of specific experience in treating people with "gender identity" being a matter for cross examination. The trial court excluded the defendant's expert citing several cases for the proposition that "courts are suspicious of purported expertise premised solely or primarily on a literature review. 36 " This probably represents an extreme view and this case has not been reviewed by the federal circuit court of appeals for that district, but it does demonstrate the impact that Kumho has had. On the good side, it gives credit for true experience. On the bad side, it excludes expert testimony that would have been admitted, probably without objection, before Daubert and would have been likely admitted under a Daubert inquiry. 3. The Factusal Foundation of the Opinion. Experts who have excellent credentials have been excluded because a court felt the factual foundation for the opinion lacked reliability. In Clark v. Takata Corp:n the Seventh Circuit affirmed a trial judge's exclusion of an expert with a Ph.D. in mechanical engineering who was a Professor-Director Emeritus at a graduate center for biomedical engineering and had worked as a consultant in the field of biomechanics and mechanical engineering. The issue in the case was whether or not the seat belt system was defective in that the buckle released during a rollover causing the plaintiff to be paralyzed. The trial judge excluded the plaintiff's expert's testimony because the plaintiff "... had come forward with no evidence that would establish that his lap belt came undone before or during the accident. 38 " 58

58 4. Testing. Many experts have taken the position that "testing" is the answer to Daubert and Kumho. Where a proposition can be reasonably tested, testing probably should be conducted. On the other hand, the testing must enhance the reliability of an experts opinion to be of benefit. Testing may create as many problems as it solves. This is what happened in the pre-kwnho case of Lytle v. Ford Motor Company, 696 N.E.2d 465 (Ind. App. 1998). The plaintiffs offered expert testimony that the restraint system in their Ranger was defective in that the seat belt buckle could release under certain circumstances and that the plaintiff's buckle did release, which caused her to sustain catastrophic injuries. These experts were both graduate mechanical engineers. One had a Masters degree in mechanical engineering. Both had extensive experience in the development and/or analysis of restraint systems. One of the experts had experience in the auto industry working for General Motors. There was testing done showing that the buckle would release under certain forces. They were unable to demonstrate that these forces actually can or did occur in the instance at issue. While other reasons were given essentially the testimony went out with the testing. What problems would they have had getting their testing into evidence if they had shown that Ford, or others in the appropriate industry tested the buckles exactly the same way? The above cases are merely examples. It is not possible to do an exhaustive analysis of the over 600 cases that have examined Kumho since it was decided. That would likely be of little benefit. As one would expect there are great variances in the results. The one clear thread that weaves through all of them is that documenting those things that enhances the reliability or trustworthiness have to be addressed. Any "strategies" as to how to present expert testimony are out the window. Instead of preparing for cross examination experts must prepare for the opportunity to be cross-examined. Conclusion Kumho only provides one universal "factor" to measure the admissibility of expert testimony, namely, the comparison of the experts "methodology" used in court to the methodology used in the every day practice. This should benefit practicing engineers. It is not enough to simply say that the engineer follows the regular practice. This must be documented. This can be done two ways. One is through publications. The other is by showing that reached his or her conclusions exactly the same way the other party does in its own practice. The expert needs to be prepared to participate in discovery. A "check list" for the attorney who hires the expert should include a search for evidence that demonstrate the expert's methodology is as good or better than the other party's. 59