Authored by Edward J. Imwinkelried
Abstract
Expert testimony is presented in the vast majority of cases tried in the United States. In the early 1990s, the Rand Institute released a study regarding the use of expert testimony in American trials. The study found there was an average of 3.3 experts per trial. A more recent estimate puts the figure at 4.3 experts per trial. Given these figures, some commentators have suggested trial in the United States is evolving into trial by expert.
Although courts and commentators sometimes refer to “the” use of expert testimony in the singular, in truth witnesses with expert credentials can play four different roles at trial. Suppose that an eminent toxicologist is driving to work. As she approaches an intersection, she sees a car run a red light and strike a pedestrian. Like any eyewitness under Federal Rule of Evidence 602, at trial she could testify to the facts she personally observed. She may possess a Ph.D., but that credential does not render her incompetent to testify to a fact any layperson could testify in court. Now assume after witnessing the accident, she stops to render assistance. While she is standing near the car that ran the red light, she encounters the driver exiting his car. She notes that his eyes are red, there is a strong odor of alcohol on his breath, and his speech is badly slurred. Under Federal Rule of Evidence 701, at trial she could testify to her lay opinion that the driver was intoxicated. Again, her educational background would not preclude her from stating an opinion that any lay witness could testify in court. Next, suppose at trial, the prosecutor or plaintiff calls a police officer who testified the intoxilyzer reading from the scene indicated the driver’s breath alcohol concentration was in excess of the jurisdiction’s per se drunk driving statute. When the toxicologist later takes the stand, the prosecutor or plaintiff could ask her to testify about the general reliability of intoxilyzer technology as a method of estimating breath alcohol concentration. Federal Rule of Evidence 702 states that an expert may testify in the form of “an opinion or otherwise.” The Advisory Committee Note to Rule 702 explains that the drafters deliberately included “or otherwise” to signal “an expert on the stand may give a dissertation or exposition of scientific or other principles relevant to the case, leaving the trier of fact to apply them to the facts [of the case].”
The preceding paragraph describes three different roles that a witness who qualifies as an expert can play at trial. However, in the vast majority of cases in which a trial attorney calls an expert witness, the attorney wants the expert to perform a fourth, more extensive role. The attorney is not content to have the expert describe a general scientific methodology. Rather, the attorney wants the expert to go further and testify to an opinion about the significance of a certain fact or facts in the case formed by applying the methodology to that case-specific data. In other words, after qualifying the expert as an expert, the attorney will invite the witness to: explain and validate a general scientific methodology, identify the case-specific fact or facts being evaluated, describe the application of the methodology to those facts, and thereby derive an opinion about the significance of that fact or those facts in terms of the outcome of the trial. After the adoption of the Federal Rules, the widespread, virtually universal practice emerged that judges would give juries Rule 105 instructions that the jurors could consider such “basis” secondhand reports only for the limited purpose of deciding the weight or quality of the testifying expert’s opinion and reasoning.
Recently, two Supreme Court decisions have posed the question of whether that practice is consistent with the Sixth Amendment’s Confrontation Clause. In a 2012 decision, Williams v. Illinois, a rape prosecution, Williams contended the expert’s reference to a secondhand report violated the Confrontation Clause. On the one hand, a five-justice majority voted to affirm the defendant’s conviction. On the other hand, a different five-justice majority adopted the view that the use of the secondhand report was necessarily hearsay. Given the importance of the “muddle” among the lower courts, it was predictable that eventually, the Court would revisit this question. The Court did so in mid-2024 in Smith v. Arizona, a decision that has already garnered considerable attention. The purpose of this short Essay is to suggest a limited reading of the majority opinion in Smith that will allow Rule 703 to continue to operate as intended outside the context of Confrontation Clause jurisprudence.
American Journal of Trial Advocacy 