In this month's column I discuss two important decisions the New York Court of Appeals rendered on evidence issues during 2007. The first, People v. LeGrand, 8 NY3d 449 (2007), reversed a murder conviction because expert testimony offered by the defendant regarding the reliability of eyewitness identifications had been excluded. The second, Rivera v. Anilesh, 8 NY3d 627 (2007), held that evidence of a dentist's routine practice when administering anesthetic injections should have been considered when ruling on a summary judgment motion in a malpractice case.

The 'LeGrand' Case

People v. LeGrand arose from the 1991 stabbing of a livery cab driver. It was not until 1999 that the defendant was charged with the crime. The People's case was based solely on identifications made by witnesses to the incident, as there was no forensic or other physical evidence connecting the defendant to the stabbing. A first trial, in April 2001, ended with a hung jury.

Before his June 2001 retrial, the defendant moved to introduce expert testimony to "educate the jurors as to the weaknesses and dangers inherent in eyewitness testimony and to present them with an appropriate perspective by which to judge such testimony." Specifically, the expert would testify as to research findings regarding the effect of "weapon focus," the lack of correlation between witness confidence and accuracy of identification, the effect of post-event information on accuracy, and confidence malleability. The expert would not, however, give an opinion on the accuracy of any particular witness' identification.

The trial judge conducted a Frye hearing and concluded that the proposed expert testimony was inadmissible because the expert's conclusions were not generally accepted in the relevant scientific community. The defendant was found guilty of second-degree murder, and the Appellate Division affirmed unanimously, 28 AD3d 318 (1st Dept. 2006).

As it reversed the conviction and remanded the LeGrand case, the Court of Appeals took what should probably be the final step of a 180-degree turn over the past quarter century in the treatment of expert testimony regarding eyewitness identifications. At the beginning of that period, the evidence was usually subject to per se exclusion. Courts often said that the issue was not a proper subject of expert testimony, because it invaded the province of the jury, see, e.g., People v. Valentine, 53 AD2d 832, 832-33 (1st Dept. 1976), or because the weaknesses of eyewitness identifications were a matter of common knowledge, see, e.g., People v. Foulks, 143 AD2d 1038 (2d Dept. 1988). Other courts considered it excessively prejudicial, see, e.g., United States v. Fosher, 590 F.2d 381, 383 (1st Cir. 1979), or thought that the alternatives available, particularly cross-examination and cautionary instructions, were adequate for impressing on the jurors the potential infirmity of eyewitness identifications, see, e.g., People v. Slack, 131 AD2d 610 (2d Dept. 1987).

That approach began to change through the 1980s. Even as additional scientific research was accumulating, the courts were becoming more receptive to expert evidence that could simply assist the jury, even if it was not in any sense "necessary" to the jury's functioning. See, e.g., People v. Cronin, 60 NY2d 430, 433 (1983). They were also recognizing the limits of cross-examination and instructions, as shown by the admission of expert testimony regarding credibility in sexual and child abuse cases. See, e.g., People v. Keindl, 68 NY2d 410, 422 (1986); People v. Taylor, 75 NY2d 277, 289 (1990).

In 1990 the Court of Appeals upheld the exclusion of expert testimony concerning factors that may influence a witness' perception and memory and affect the reliability of eyewitness identifications, but as a matter of discretion. In People v. Mooney, 76 NY2d 827 (1990), the Court held that it "need not decide whether the expert testimony sought to be presented was of the type that could, as a matter of law, properly be admitted," because "the trial court based its decision to exclude the testimony in the exercise of its sound discretion." Now-Chief Judge Judith Kaye dissented, arguing that the majority had implied that the trial judge's discretion was unreviewable, because it made no effort to address the reasons offered for exclusion. 76 NY2d at 828-833.

Different Reasoning

The next time the issue came before the Court of Appeals the result was the same, but the reasoning was quite different. In People v. Lee, 96 NY2d 157 (2001), which came down between the first and second trials in LeGrand, the Court specifically rejected the trial judge's premise in Mooney that expert testimony was admissible only when "necessary"; now the test for admissibility is whether the jury "'would be benefitted by the specialized knowledge of an expert,'" and whether the expert's testimony "'would aid a lay jury in reaching a verdict.'" 96 NY2d at 162. Because there was evidence corroborating the identifications in Lee, the expert testimony would be relatively less helpful, so there was no abuse of discretion when it was excluded. See 96 NY2d at 163; see also People v. Young, 7 NY3d 40, 45 (2006).

With the Court of Appeals confirming in Lee and Young that research concerning eyewitness identification was a proper subject of expert testimony, its recent decision in LeGrand was significant in recognizing that expert testimony regarding the credibility of eyewitness identifications could satisfy the reliability requirement for expert testimony about scientific principles and techniques. In New York, that requirement is derived from the classic decision of Frye v. United States, 293 F. 1013, 1014 (D.C. Cir. 1923). As the Court recently restated it in Parker v. Mobil Oil Corp., 7 NY3d 434, 446 (2006): "[T]he Frye test asks 'whether the accepted techniques, when properly performed, generate results accepted as reliable within the scientific community generally.'"

The trial judge in LeGrand had conducted a Frye hearing and had precluded the expert testimony on the ground that the principles about which the expert was to testify did not have general acceptance in the relevant scientific community. 196 Misc2d 179 (Sup. Ct. N.Y. Co. 2002). The Court of Appeals held that there was no error in conducting the Frye hearing. However, it implied, by reference to the admission in other cases of "a qualified expert's testimony regarding research findings on patterns of human behavior" without such a hearing, that the hearing might not have been necessary. And it strongly suggested that a Frye hearing would not be required in the future because "[a] court need not hold a Frye hearing where it can rely upon previous rulings in other court proceedings," and "a number of New York courts have found that the Frye test has been met after considering whether factors that may affect eyewitness identifications should be admitted." 8 NY3d at 457-58.

Defense Expert's Testimony

In this case, at the Frye hearing the defense offered a survey indicating that an overwhelming majority of experts in the field accepted the principles behind the four factors affecting eyewitness identifications as to which the expert would testify. The People's expert disputed the methodology and results of the survey. The Court of Appeals agreed that the survey alone was not dispositive, but it held that "the defense expert's testimony contained sufficient evidence to confirm that the principles upon which the expert based his conclusions are generally accepted by social scientists and psychologists working in the field" regarding three of the factors:

• correlation between confidence and accuracy of identification,

• the effect of post-event information on the accuracy of identification, and

• confidence malleability.

Only the fourth factor, weapon focus, lacked sufficient evidence of general acceptance to be admissible. 8 NY3d at 458.

The Court also noted that an expert offered by the People at the Frye hearing would presumably be available to testify before the jury. 8 NY3d at 459. To me, the implication that juries can be trusted to weigh conflicting information from experts in cases like this represents a significant change from attitudes expressed less than 25 years ago.

The Court concluded by reiterating that trial judges still have considerable discretion regarding the admissibility of expert testimony considering the reliability of eyewitness identifications. It noted that "not all categories of such testimony are applicable or relevant in every case." And it specifically referred to the factor found significant in Lee and Young: "the admissibility of such evidence would also depend upon the existence of sufficient corroborating evidence to link defendant to the crime. In the event that sufficient corroborating evidence is found to exist, an exercise of discretion excluding eyewitness expert testimony would not be fatal to a jury verdict convicting defendant." 8 NY3d at 459.

Habit Evidence

Rivera v. Anilesh had its genesis when the plaintiff suffered an infection after the defendant dentist extracted a tooth. The plaintiff's theory was that the infection was attributable to a misplaced injection of anesthetic. When a first injection intended to numb the area near the tooth to be extracted did not obtain the desired effect, the dentist allegedly gave another injection. A second injection should be given at the same site as the first, to limit susceptibility to infection; the plaintiff's expert said that the second one in this case had not been given at the proper place, based on the plaintiff's testimony about pain she felt at the time. 8 NY3d at 631-33.

In support of her motion for summary judgment, the defendant offered her deposition testimony that, while she could not recall what happened during the plaintiff's procedure, such anesthetic injections were a "routine procedure" that she did "every day" to "at least three to four or five" patients, and that she had been practicing as a dentist since 1982. She explained that a second injection was required in 15 percent-20 percent of her cases, and she described the injection procedure step by step, including that she administered a second injection, if necessary, at the same site as the first. She also indicated that if a patient complained of unusual pain, or if any other unexpected events occurred during the treatment, she would make a notation in the patient's chart, but that no such note existed for the plaintiff. 8 NY3d at 632.

The trial court granted summary judgment to the defendant, finding that she had established that she acted in accordance with generally acceptable dental practices, and that even if she gave the second injection in the wrong location, the plaintiff's expert's causation opinion was speculative. The Appellate Division reversed, with a majority concluding that the dentist's testimony about her customary practice for administering anesthesia was inadmissible and could not be used to raise an inference that she had adhered to her habitual protocols when she treated the plaintiff. That conclusion reflected a belief that the testimony did "not take into consideration the unique circumstances surrounding each individual patient." 32 AD3d 202, 225 (1st Dept. 2006).

Although the Court of Appeals affirmed reversal of the summary judgment (because the plaintiff's testimony put in issue whether the second injection was made at the site of the first, 8 NY3d at 636), it held that the dentist's testimony as to her habit should have been considered. The principles for admitting such evidence had been established in Halloran v. Virginia Chems., 41 NY2d 386, 389-92 (1977): Where the proof demonstrates "a deliberate and repetitive practice" by a person "in complete control of the circumstances," as opposed to "conduct however frequent yet likely to vary from time to time depending upon the surrounding circumstances," "a party should be able, by introducing evidence of such habit or regular usage, to allow the inference of its persistence . . . on a particular occasion." 8 NY3d at 633-34.

The Court observed that it had not considered habit evidence in the context of medical or dental procedures since Halloran, but it noted ("[w]ithout commenting on the propriety of [the] decisions") that the appellate divisions had generally admitted evidence of routine practices regarding normal documentation and notification protocols, warnings to patients, and certain noninvasive medical procedures, while excluding evidence of surgical practices "under the theory that every surgery is necessarily unique and varies depending on the nature of the patient's medical condition and the actions of the doctor." 8 NY3d at 634-35.

In this case, admissibility of the defendant's testimony regarding her technique for administering anesthesia was justified by the frequency with which she used it and the nature of the conduct described. Her testimony indicated that, "[e]ven by a conservative estimate," she had performed the procedure "in the same manner thousands of times." And she described a specific procedure within the accepted standard of care for dentistry, with no indication that it "would vary from patient to patient depending on the particular medical circumstances or physical condition of the patient." Thus, the testimony satisfied the Halloran principles and was properly considered by the trial judge in ruling on the summary judgment motion. 8 NY3d at 635-36.

Michael M. Martin is the Distinguished Professor of Law and associate dean for administration at Fordham Law School.