¶ 66. (dissenting). The majority concludes that the circuit court did not erroneously exercise its discretion in excluding the expert testimony on eyewitness identification proffered by the defendant, and that the absence of such *49testimony did not deprive him of his constitutional right to present a defense. Because I disagree with these conclusions, and because I conclude that there was a significant failure of communication between the trial court and defense counsel regarding the admissibility of some of the proffered expert testimony, I respectfully dissent.
I
¶ 67. Wisconsin has a low threshold when it comes to the admission of expert testimony. State v. St. George, 2002 WI 50, ¶ 39, 252 Wis. 2d 499, 643 N.W.2d 777. Expert witness testimony is governed by Wis. Stat. § 907.02 (2003-04),1 which provides that if specialized knowledge will assist the trier of fact to understand the evidence or to determine a fact in issue, a qualified witness may testify. Id. Admissible expert testimony in the form of an opinion or inference is not objectionable because it embraces an ultimate issue to be decided by the trier of fact. Wis. Stat. § 907.04. Further, evidence is "relevant" if it has any tendency to make the existence of any fact more probable or less probable than it would be without the evidence. Wis. Stat. § 904.01. All relevant evidence is admissible unless otherwise precluded by the constitution, statute, or court rule. Wis. Stat. § 904.02. A trial court may preclude certain relevant evidence, "if its probative value is substantially outweighed by the danger of unfair prejudice, confusion of the issues, or misleading the jury, or by considerations of undue delay, waste of time, or needless presentation of cumulative evidence." Wis. Stat. § 904.03.
*50¶ 68. Once relevancy and the expert's qualifications are established, the reliability of the expert's testimony is a credibility issue to be determined by the fact finder. State v. Stinson, 134 Wis. 2d 224, 234, 397 N.W.2d 136 (Ct. App. 1986); State v. Shaw, 124 Wis. 2d 363, 367, 369 N.W.2d 772 (Ct. App. 1985). "Whether such relevant evidence should be excluded [] goes to the trial court's discretion to weigh the probative value of the evidence against the possibility of prejudice or other factors which might impede the orderly and expeditious disposition of the issues at trial." State v. Wollman, 86 Wis. 2d 459, 464, 273 N.W.2d 225 (1979) (citing Chapin v. State, 78 Wis. 2d 346, 353, 254 N.W.2d 286 (1977); Kelly v. State, 75 Wis. 2d 303, 319, 249 N.W.2d 800 (1977)). As such, in exercising its discretion regarding expert testimony, the trial court must articulate a reasonable explanation that demonstrates that the court considered whether the probative value of the testimony was substantially outweighed by its potential prejudicial effects, or whether any other statute, constitutional provision, or court rule impacts its admissibility. This decision is guided by, and the result should be consistent with, the State's approach of liberally admitting expert testimony.
¶ 69. Applying the erroneous exercise of discretion standard of review to the facts of this case, the majority concludes that the trial court's decision to exclude the expert testimony was a proper exercise of its discretion in accordance with accepted legal standards and in accordance with the facts of the record. Majority op., ¶¶ 10 — 17. The majority bases its determination on the fact that the circuit court felt that everything the expert would testify to with respect to the factors that may influence a witness's ability to identify a stranger was within the common knowledge *51and sense and perception of the jury. Majority op., ¶ 13. The majority further finds fault with defense counsel's inability to articulate the basis upon which the factors influencing the reliability of eyewitness identifications would assist the trier of fact. Majority op., ¶ 14. I respectfully disagree with the majority's analysis and its conclusion.
¶ 70. Numerous factors can influence a witness's ability to accurately identify a person or an event.2 Such factors include, but are not limited to, (1) the stressfulness of the event for the eyewitness;3 (2) whether the race, gender, or age of the witness differs from that of the person observed;4 and (3) whether the event in*52volved "weapon focus."5 Just last term, we recognized that "[t]he research strongly supports the conclusion that eyewitness misidentification is now the single greatest source of wrongful convictions in the United States, and responsible for more wrongful convictions than all other causes combined." State v. Dubose, 2005 WI 126, ¶ 30, 285 Wis. 2d 143, 699 N.W.2d 582. We should not expect the ordinary person in the community, without assistance, to be able to grasp and comprehend the complicated processes and limitations of how memory, cognition, relative judgment, and transference work.
¶ 71. Furthermore, several recent scientific studies have proven the significant negative impact that certain factors have on an eyewitness's identification of a stranger.6 As the majority recognizes, these factors *53include the relative reliability of sequential versus simultaneous lineups, relative judgment, transference, the absence of a reliable relationship between the confidence of a witness and the accuracy of the identification, and examples of people wrongly convicted of crimes based solely on an incorrect identification. See majority op., ¶ 13. These factors also include, (1) whether the eyewitness is told prior to the photo array or lineup that a suspect has been detained and may be present for the identification;7 (2) whether the "fillers" match the eyewitness's description of the perpetrator;8 and (3) whether the eyewitness is given positive feedback during or immediately following the identification.
¶ 72. The defense in this matter was that someone other than the defendant committed these offenses, and that Shomberg was mistakenly identified as the perpetrator. Relying on established scientific research, the expert testimony that he sought to introduce would have addressed factors that have a significant bearing on a witness's ability to identify a stranger, as well as explained how these factors impact the accuracy of a *54witness's recollection. Notwithstanding the cross-examination of the eyewitnesses and jury instructions, expert testimony would still have assisted the trier of fact.9 This testimony would certainly have had a tendency to make the existence of each witness's identification of Shomberg as the perpetrator less probable than it would have been without it, and therefore relevant to his innocence. This court has previously recognized that the ability of a witness to perceive persons, objects, and events, and then to correctly recall and relate those perceptions at trial, is relevant to the credibility of that witness's testimony. Hampton v. State, 92 Wis. 2d 450, 455-56, 285 N.W.2d 868 (1979). *55Indeed, the trial court in Hampton recognized that the expert was permitted to testify regarding those factors which the expert believed could influence eyewitness identifications.10 Id. at 458. See also Stinson, 134 Wis. 2d at 235 (where the court of appeals concluded that bite mark evidence presented by an expert witness can be a valuable aid to a jury in understanding and interpreting evidence); and Shaw, 124 Wis. 2d at 368-69 (where the court of appeals concluded that the expert witness's testimony that fingernail clippings could be useful for identification purposes and that the defendant's clippings matched those found at the scene tended to make the fact of defendant's guilt more probable than it would be without the evidence).
¶ 73. Defense counsel raised these issues concerning the admissibility of Shomberg's expert witness testimony prior to the trial. The areas of testimony sought were included in the motion. The background and qualifications of the expert were attached to the motion. Defense counsel attempted to explain the relevance of the testimony in the pretrial hearing prior to *56the waiver of any jury.11 Because the scientific analysis of perception and memory recollection is beyond the general knowledge and experience of the average juror, as well as many judges, there can be no doubt that the testimony of the expert would have assisted the trier of fact. Cross-examining the eyewitness is simply no substitute for expert testimony regarding the witness's ability to make a correct identification.12
¶ 74. In this matter, it is obvious that what we have here is failure to communicate between the trial court and defense counsel. The whole point of calling an expert witness to the stand is to provide the trier of fact with information in the form of testimony it would not otherwise have available to it in rendering a decision in contested litigation. Such testimony was available to the trier of fact in this action, but the trial court excluded that testimony from the evidence. Because relevance is the standard for admissibility under Wis. Stat. § 907.02 and the proffered expert testimony in this case is relevant, because the proffered expert testimony would assist the trier of fact, and because the witness in this case is qualified to give the testimony proffered,13 I would conclude that the decision of the trial court to exclude the expert testimony regarding the factors surrounding eyewitness identification was clearly erroneous.
*57II
¶ 75. In a criminal trial, an accused's right to due process is, in essence, the right to a fair opportunity to defend against the State's accusations.14 The right to call witnesses on one's own behalf has long been recognized as essential to due process. Chambers v. Mississippi 410 U.S. 284, 294 (1973); In re Oliver, 333 U.S. 257, 273 (1948). At a minimum, criminal defendants have "the right to put before the [trier of fact] evidence that might influence the determination of guilt." Taylor v. Illinois, 484 U.S. 400, 408 (1988) (quoting Pennsylvania v. Ritchie, 480 U.S. 39, 56 (1987)). Few rights are more fundamental. Webb v. Texas, 409 U.S. 95, 98 (1972); Washington v. Texas, 388 U.S. 14, 19 (1967). This right is an essential attribute of the adversary system itself. Taylor, 484 U.S. at 408-09 (citing United States v. Nixon, 418 U.S. 683, 709 (1974)).
¶ 76. An accused does not have an unfettered right to offer testimony that is "incompetent, privileged, or otherwise inadmissible under standard rules of evidence."15 Taylor, 484 U.S. at 410; Chambers, 410 U.S. at 302. Accordingly, this court has developed a two-part *58inquiry with respect to a defendant's constitutional right to the admissibility of proffered expert witness testimony. St. George, 252 Wis. 2d 499, ¶ 54.
¶ 77. First, the defendant must satisfy each of the following four factors regarding admissibility:
1) The testimony of the expert witness [meets] the standards of Wis. Stat. § 907.02 governing the admission of expert testimony.
2) The expert witness's testimony [is] clearly relevant to a material issue in this case.
3) The expert witness's testimony [is] necessary to the defendant's case.
4) The probative value of the testimony of the defendant's expert witness outweigh[s] its prejudicial effect.
Id. (footnotes omitted). Second, if the defendant satisfies these four factors to establish a constitutional right to present expert testimony, a court must determine whether the defendant's right to present the proffered evidence is nonetheless outweighed by the State's compelling interest to exclude the evidence. Id., ¶ 55.
¶ 78. As to the first part of the inquiry, the majority concludes that the first, second, and fourth factors are arguably met (making no assessment about the qualifications of the expert). Majority op., ¶ 28. The majority focuses on the third factor, concluding that the *59defendant failed to establish that the expert eyewitness testimony was necessary to his case. Id. The majority reasons that defense counsel was able to convey adequately the concepts of relative judgment and recognition memory, as well as the factors relevant to the unreliability of eyewitnesses' testimony, in his cross-examinations of each of the eyewitnesses. Id. The majority is mistaken. Although cross-examination may have touched upon each witness's perceptions and recollections of the event in question, cross-examination did not allow the defense the opportunity to explain to the trier of fact how the factors that impact the perception, memory, and recollection, as established through scientific research, would have affected the ability of each witness to correctly identify the perpetrator of these offenses.
¶ 79. Furthermore, the majority's reasoning fails to properly take into account what would satisfy the "necessary to the defendant's case" prong from St. George, and therefore leads to a faulty conclusion. In Taylor, the United States Supreme Court ruled that, under the Sixth Amendment, an accused not only has the right to confront the prosecution's witness through cross-examination in order to challenge their testimony, the accused also "has the right to present his [or her] own witnesses to establish a defense. This right is a fundamental element of due process of law." Taylor, 484 U.S. at 409 (citation omitted). The right to present the testimony of witnesses "provides the defendant with a sword that may be employed to rebut the prosecution's case." Id. at 410. "The decision whether to employ [that right] in a particular case rests solely with the defendant." Id. But that right includes "the right to put before [the trier of fact] evidence that might influence the determination of guilt." Id. at 408 (quoting Ritchie, 480 U.S. at 56).
*60¶ 80. The majority asserts that " 'as in Scheffer, the court... heard all the relevant details of the charged offense from the perspective of the accused,' and the exclusion of expert testimony 'did not preclude him from introducing any factual evidence.'" Majority op., ¶ 36 (citing United States v. Scheffer, 523 U.S. 303, 317 (1998)). The majority points out that Scheffer was merely precluded from " 'introducing expert opinion testimony to bolster his own credibility,' and therefore concluded that 'respondent's defense was [not] significantly impaired by the exclusion ...."' Id. This is not what occurred here. The defendant did not offer the expert testimony merely to bolster his credibility. Instead, the defendant offered the expert testimony to address factual concerns, rooted in scientific studies, regarding the problems inherent in eyewitness testimony. Had the proffered testimony been merely cumulative, I would agree with the majority. It is not.
¶ 81. Expert testimony becomes necessary to the presentation of the defense if it might influence the determination of guilt or innocence. Given the facts here that Shomberg's defense was that someone else committed these offenses, that the victim could not identify him at all but picked him out of the lineup because he was the best of six in the lineup, and that the other witness was told that a lineup would be performed after the suspect was caught, and he was only 90 percent sure of his identification, I would conclude that the testimony of the expert witness, under these circumstances, certainly could affect the determination of guilt or innocence in this case. Consequently, this evidence was necessary to the defendant's case. While Shomberg may have been able to cross-examine each of the eyewitnesses, he was nevertheless deprived of his *61opportunity to present his own witness with respect to the factors that impact eyewitness identification.
¶ 82. Having concluded that Shomberg has satisfied all four factors in the first part of the St. George inquiry, I also conclude that the State has failed to satisfy the second prong, that it had a compelling interest to exclude the evidence. Accordingly, the exclusion of Shomberg's expert testimony violated his constitutional right to present a defense.
r-H hH I — I
¶ 83. The State argues that even if the circuit court erred in excluding the expert witness testimony-in this case, the error is harmless. I disagree. Where the exclusion of the evidence deprives a criminal defendant of the constitutional right to present a defense, the harmless error rule is inapplicable. See State v. Pulizzano, 155 Wis. 2d 633, 655-56, 456 N.W.2d 325 (1990); State v. Statesman, 221 Wis. 2d 178, 187-88, 585 N.W.2d 181 (Ct. App. 1998).
IV
¶ 84. The circuit court's decision to exclude Shomherg's expert witness from testifying about the factors that have a bearing on an eyewitness's ability to identify a stranger was clearly erroneous. Shomberg was therefore deprived of his constitutional right to present a defense. In addition, the harmless error rule is inapplicable under these circumstances. I would therefore reverse the judgment of conviction, and remand this matter to the circuit court to conduct a new trial. Accordingly, I respectfully dissent.
All references to the Wisconsin Statutes are from 2003-04.
In general, people overestimate eyewitness accuracy and fail to understand the factors that affect it. See Gary L. Wells & Elizabeth A. Olson, Eyewitness Testimony, 54 Annu. Rev. of Psychol. 277, 284-85 (2003).
See United States v. Sebetich, 776 F.2d 412, 419 (3d Cir. 1985) ("There is evidence that stress decreases the reliability of eyewitness identifications, contrary to common understanding.").
See, e.g., Brown v. Davis, 752 F.2d 1142, 1146 (6th Cir. 1985) ("Those experienced in criminal trial work or familiar with the administration of justice understand that one of the great problems of proof is posed by eyewitness identification, especially in cross-racial identification.") (citation omitted); United States v. Telfaire, 469 F.2d 552, 559 (D.C. Cir. 1972) (The available data, while not exhaustive, unanimously supports the widely held commonsense view that members of one race have greater difficulty in accurately identifying members of a different race.... Yet, we have developed a reluctance — almost a taboo — to even admit the existence of the problem, let alone provide the jury with the information necessary to evaluate its impact."); John P Rutledge, They All Look Alike: The Inaccuracy of Cross-Racial Identifications, 28 Am. J. Crim. L. 207 (2001); Peter N. Shapiro & Steven Penrod, Meta-Analysis of *52Facial Identification Studies, 100 Psychol. Bui. 139 (1986) (studies have found that race and gender play a role in the accuracy of facial identification); Daniel B. Wright & Joanne N. Stroud, Age Differences in Lineup Identification Accuracy: People Are Better With Their Own Age, 26 Law Hum. Behav. 641 (2002).
Otto H. MacLin, M. Kimberly MacLin, Roy S. Malpass, Race, Arousal, Attention, Exposure, and Delay: An Examination of Factors Moderating Face Recognition, 7 Psychology, Public Policy, & Law 134 (2001) (Weapon focus is "the phenomenon whereby the presence of a weapon diverts attention from other aspects of a scene.").
See United States v. Moore, 786 F.2d 1308, 1312 (5th Cir. 1986) ("The scientific validity of the studies confirming the many weaknesses of eyewitness identification cannot be seriously questioned at this point."); United States v. Langan, 263 F.3d 613, 622 (6th Cir. 2001) ("[T]he science of eyewitness perception has achieved the level of exactness, methodology, and reliability of any psychological research." (internal quotations omitted)).
Studies have shown that when eyewitnesses are instructed prior to an identification that the real perpetrator "may or may not be present" in the photo array or lineup and that the investigation will continue regardless of the identification, the instruction can reduce mistaken identification by up to 41.6 percent. Wells & Olson, Eyewitness Testimony, supra.
See, e.g., Technical Working Group on Eyewitness Evidence, Eyewitness Evidence: A Guide for Law Enforcement, Washington, D.C.: National Institute of Justice, 29 (1999) ("Select fillers who generally fit the witness' description of the perpetrator. When there is a limited/inadequate description of the perpetrator provided by the witness, or when the description of the perpetrator differs significantly from the appearance of the suspect, fillers should resemble the suspect in significant features.").
Jurors often place too much emphasis on eyewitness confidence. See Jennifer Devenport et al., Eyewitness Identification Evidence: Evaluating Commonsense Evaluations, 3 Psy-chol., Pub Pol'y & L. 338,347-48 (1997). See also Farris v. State, 818 N.E.2d at 72-73 (Ind. 2004) ("investigators' unintentional cues (e.g., body language, tone of voice) may negatively impact the reliability of eyewitness evidence."). While Judge Fiedler had been informed that Shomberg would waive his right to a jury trial, no waiver had been accepted by the trial court at the time Judge Fiedler made his ruling regarding the admissibility of expert testimony. The court had no way of knowing whether Shomberg would change his mind prior to accepting Shomberg's waiver.
Some studies show that jury instructions "do not effectively teach jurors about how to evaluate eyewitness testimony." Michael R. Lieppe, The Case for Expert Testimony About Eyewitness Memory, 1 Psychol., Pub. Pol'y, & L. 909, 923 (1995) (citing Brian Cutler, et al., Nonadversarial Methods for Sensitizing Jurors to Eyewitness Evidence, 20 J. Applied Psychol. 1197 (1990)). See also United States v. Downing, 753 F.2d 1224, 1230 n.6 (3d Cir. 1985) ("To the extent that a mistaken witness may retain great confidence in an inaccurate identification, cross-examination can hardly be seen as an effective way to reveal the weakness in a witness' recollection of an event.")
In Hampton, this court assumed that some expert testimony should have been permitted that would make available to the jury the scientific evidence the defendant deemed necessary for the determination of the issue. Hampton v. State, 92 Wis. 2d 450, 455-56, 285 N.W.2d 868 (1979). This court nevertheless upheld the limitations that precluded the expert from applying those factors to the concrete circumstances of that case and from giving his own opinion as to the reliability of the identification of the defendant. Id. at 458-59. The majority, sub silencio, now apparently rejects this assumption that was readily accepted in Hampton, and would allow a trial court to preclude scientific evidence concerning eyewitness identifications and the factors that can influence them from being presented to the jury, notwithstanding its relevance.
Unlike the majority, I conclude that counsel's efforts at presenting the issue before the trial court more than satisfied the requirements of Wis. Stat. § 901.03(l)(b). The substance of the testimony was made known to the judge in the motion, the attachment to the motion, and at the hearing prior to the jury waiver and the trial.
See, supra, n.9.
This was not contested at the trial court level.
The constitutional right to present evidence is grounded in the Confrontation and Compulsory Clauses of Article I, § 7 of the Wisconsin Constitution and the Sixth Amendment to the United States Constitution. State v. Dodson, 219 Wis. 2d 65, 72, 580 N.W.2d 181 (1998).
The majority asserts that United States v. Scheffer, 523 U.S. 303, 308 (1998), has narrowed the Court's holding in Taylor v. Illinois, 484 U.S. 400, 408 (1988), with regard to a defendant's right to present a defense. Majority op., ¶ 35. However, Scheffer cites Taylor with approval and simply recognizes some of the types of limitations discussed in Taylor. These "other legitimate interests" that may constitutionally limit a defendant's right to present eyewitness testimony are the established rules of evidence. As Taylor explicitly recognized, a defendant does not *58have an unfettered right to present testimony that is "incompetent, privileged, or otherwise inadmissible under standard rules of evidence." Taylor, 484 U.S. at 410. Following the Taylor rationale, Scheffer upheld a rule that made polygraph evidence inadmissible because it was consistent with other rules of evidence regarding the reliability of evidence, and therefore did not "implicate a sufficiently weighty interest of the defendant to raise a constitutional concern." Scheffer, 523 U.S. at 309.