AuthorImwinkelried, Edward J.


"[C]larity is the hardest thing of all."--Julian Barnes (1)

It is a commonplace observation that expert testimony figures prominently in modern trials. In 1980, the National Center for State Courts released the results of a nationwide survey of trial judges and attorneys. (2) In that survey, the respondents indicated that they encountered expert testimony in approximately one-third of their trials. (3) However, by the early 1990s the use of expert testimony had dramatically accelerated and become much more widespread. (4) By the time of the famous 1990 RAND Corporation study of the use of such testimony in California Superior Court civil trials, (5) the researchers discovered that experts appeared in 86 percent of the cases. (6) On average, there were 3.3 experts per trial. (7) A more recent study reported that that figure has risen to 4.3 experts per trial. (8) One prosecutor has claimed that today expert testimony on such topics as DNA typing is "the backbone of every circumstantial evidence case." (9) One commentator committed only mild hyperbole when he asserted that in the United States, trial by jury is evolving into trial by expert. (10)

Article VII of the Federal Rules of Evidence contains the provisions governing the admissibility of opinion testimony. (11) While Rule 701 controls the admission of lay opinion testimony, Rules 702-06 contain numerous prescriptions regulating expert testimony. (12) Some of those provisions surface again and again in the published opinions. (13) For example, when the judge faces the threshold question of whether there is an absolute or relative necessity for resorting to expert testimony, Rule 702(a) is on point; 702(a) announces that the judge must find that the testimony would "help the trier of fact to understand the evidence or to determine a fact in issue." (14) If the judge concludes that an expert opinion on the subject would be helpful, the proponent must then lay the other elements of the foundation. (16) To begin with, under the Supreme Court's celebrated 1993 Daubert decision, the proponent must establish that the expert employed a reliable methodology; (16) in the words of Rule 702(c), these must be "reliable principles and methods." (17) Next, the expert applies that methodology to assess the significance of certain facts in the case, such as a DNA sample or a psychiatric patient's case history. Rule 703 speaks to the "kinds" of facts the expert applies the methodology to, (18) and Rule 702(b) announces that the expert's opinion must be "based on sufficient facts or data." (19) Rule 702(d) demands proof that the expert "reliably applied" the methodology to those facts. (20) Ultimately, the application of the methodology to the facts of the case yields the expert's final opinion. Rule 704 addresses the limitations on the wording of that opinion, (21) and Rule 705 discusses which components of his or her reasoning the expert may withhold on direct examination. (22) At least at first blush, these provisions seem to constitute a detailed, comprehensive framework for a judge passing on the admissibility of expert testimony.

Given this apparently comprehensive framework and the frequency with which expert testimony is proffered at trial, one would hope that by now the courts would have developed a clear, coherent analysis to assess the admissibility of expert testimony. After all, the basic structure of the Rule 702-06 scheme has been in place for almost half a century. (23) In their earliest form, these provisions became law on July 1, 1975, the effective date of the Federal Rules of Evidence. (24) Yet, sadly, forty-seven years later a coherent analytic framework is still lacking. Even today both judges (25) and academic commentators loudly complain that the judicial application of the Federal Rules' expert testimony provisions is confused and unsatisfactory. (26) In particular, the critics assert that despite the thousands of cases applying Rules 702-06 to date, it remains unclear to what extent and how the courts should evaluate the "factual" bases of expert opinion testimony. (27) These questions relate to the fundamental problem of the tripartite division of labor with respect to the factual bases: What is the extent of the judge's authority, what role does the jury play, and which issues, if any, does the expert have the final say on?

This short Article does not undertake the Herculean task of trying to end all the controversies surrounding Article VII. For example, this Article does not address the longstanding, thorny problem of determining the reliability of methodologies used by nonscientific expert witnesses. (28) Rather, the limited objective of this Article is to clarify the regulation of the "factual" bases of expert opinion testimony. One thesis of this Article is that the root source of the confusion is the failure of many courts to identify the key interpretive issue, namely, the meaning of the expression "facts and data"--language that appears identically in Rules 702(b), 703, and 705. Admittedly, on its face, the reference to "data" is broad enough to refer to scientific research data, such as the empirical data in studies validating new DNA methodologies--data that could be applied in multiple cases. (29) However, this Article instead argues that the language ought to be construed narrowly to apply only to case-specific facts such as the who, what, where, when, why, and how of the historical events disputed in the particular case. The Article further contends that if the courts were to embrace that interpretation of the language in Rules 702(b), 703, and 705, there would emerge a clear picture of the parameters of legitimate regulation of the factual bases of expert opinions.

To develop those theses, this Article proceeds in four parts. Parts I and II are descriptive. Part I chronicles the history of Rules 702-05, including the important 2000 amendments and the 2011 restyling. Part II then surveys the confusion in the cases about the respective roles of the judge, jury, and expert in assessing the factual bases of expert opinions. In contrast, Parts III and IV are evaluative. Part III addresses the key statutory construction question: the meaning of the expression "facts or data" in Rules 702(b), 703, and 705. Again, Part III argues for a narrow construction of that language, excluding scientific research "data" transcending the historical events in the specific case. Positing that construction, Part IV then shifts to the question of the regulation of the factual bases of expert opinions. Part IV defines the legitimate roles of the judge and expert under Article VII and, by process of elimination, the remaining, critical role of the jury in gauging the credibility of testimony setting out the factual bases for expert opinions.



    As previously stated, Article VII of the Federal Rules of Evidence contains five provisions, Rules 702 through 706, that purport to control the admissibility of expert testimony. (30) The current version of three provisions, Rules 702(b), 703, and 705, contains the language that is the focus of this Article, "facts or data." (31) If the Rules' scheme governing expert testimony is to cohere at all, those provisions must be harmonized. It is one of the most basic, (32) default principles in statutory construction that if a statutory scheme repeats the same wording in several passages, the passages should ordinarily be given the same meaning. (33) The court of appeals (34) and district court (35) cases recognizing the principle are legion. The Supreme Court itself has invoked the principle on numerous occasions. (36) Admittedly, this interpretive maxim does not operate as a full-fledged, invariable rule. (37) Rather, the maxim functions as a rebuttable presumption. (38) Nevertheless, it is a strong presumption (39) because it rests on a natural, (40) sensible assumption as to the drafters' intent. (41)

    In some situations, the presumption has special force. (42) For several reasons, this is one of those situations. To begin with, the words of these Rules were carefully chosen. The Rules of Evidence legislative package was not rushed or hurried; the Judicial Conference devoted seven years to studying the project before the Supreme Court transmitted the draft to Congress, and Congress then deliberated over the draft for more than two years. (43) Rather than rubberstamping the draft, in some cases, such as Article V on privileges, Congress made extensive changes to the draft's wording. (44) Moreover, the drafters worked on the three provisions simultaneously; as they worked on each provision, the drafters must have been aware of the other provisions. In addition, the subject matters of the three provisions are closely related in a policy sense. (45) All three Rules purport to be and are intended to be regulations of expert testimony. (46) It stands to reason that the drafters would have wanted the Rules to work together in a rational fashion. Finally, the Rules are proximate; Rules 702 and 703 are immediately adjacent, and they are separated from Rule 705 by only one provision, Rule 704. (47) The more proximate statutory provisions are, the more overpowering is the inference that the drafters intended the same language to have the identical meaning in all of the provisions. (48) Again, Article VII contains five provisions concerning expert testimony. Since the language, "facts and data," appears verbatim in the majority of those provisions, common sense dictates that the interpretation of that language is an important clue to the essential design of Article VII's scheme for regulating expert testimony. (49) In that light, we turn to the history of Rules 702, 703, and 705.

    1. Federal Rule 702

      The original version of Rule 702, which took effect in 1975, was relatively short:


To continue reading

Request your trial

VLEX uses login cookies to provide you with a better browsing experience. If you click on 'Accept' or continue browsing this site we consider that you accept our cookie policy. ACCEPT