concurring in part and dissenting in part:
I concur with the majority’s conclusion that the admissibility of expert testimony about grooming should be decided on a case-by-case basis under NRS 50.275 and Hallmark v. Eldridge, 124 Nev. 492, 189 P.3d 646 (2008). However, such testimony should be admitted in rare circumstances, and I disagree that this case warrants its admission. The State did not introduce sufficient specific evidence that Dr. Paglini was qualified to discuss grooming of child victims by sex offenders, and his testimony did not assist the jury in understanding the victim’s actions and unfairly prejudiced Perez. I also disagree with the majority’s conclusion that the expert-witness notice was sufficient.
Admission of expert testimony
Expert testimony is admissible if it meets three requirements, which we have described as the “qualification,” “assistance,” and “limited scope” requirements:
(1) [the expert] must be qualified in an area of “scientific, technical or other specialized knowledge” (the qualification requirement); (2) his or her specialized knowledge must “assist the trier of fact to understand the evidence or to determine *864a fact in issue” (the assistance requirement); and (3) his or her testimony must be limited “to matters within the scope of [his or her specialized] knowledge” (the limited scope requirement).
Hallmark, 124 Nev. at 498, 189 P.3d at 650 (second alteration in original) (quoting NRS 50.275); see also Higgs v. State, 126 Nev. 1, 18, 222 P.3d 648, 658 (2010). As I explain below, the State failed to put forth sufficient evidence to demonstrate that Dr. Paglini was qualified to offer expert testimony and the testimony that he provided failed to assist the jury.
Expert qualifications
The majority concludes that Dr. Paglini’s academic career and professional experience were sufficient to qualify him to offer the testimony on the grooming phenomenon. It notes that Dr. Paglini is a clinical psychologist who had conducted child custody evaluations, pretrial competency evaluations, death penalty evaluations, and psychosexual evaluations. However, Dr. Paglini did not identify how many of his prior evaluations involved child victims of sexual abuse or grooming, and he had not written any treatises or articles on the phenomenon.
Dr. Paglini’s principal qualification, according to his testimony, was his work preparing “risk assessments” for use in sentencing convicted sex offenders. “[I]t’s my job as a psychologist ... to educate the judge on the history of the defendant, what their violent history and sex offender history is” so the court can “understand what the risk of reoffending is towards a community” in sentencing. Continuing, Dr. Paglini testified, “You’re looking at certain variables like sex offending history .... Was there grooming involved, and what was the grooming?” Notably absent from Dr. Paglini’s testimony about his qualifications was any reference to work with victims of grooming. Rather, the focus was—and remained—on what sex offenders do that can constitute grooming.
Grooming testimony is permissible in certain child-sex-abuse cases, normally to explain the impact the grooming had on the victim’s behavior in terms of delayed reporting and the like. See NRS 50.345 (“expert testimony is not inadmissible” in sexual assault cases when offered to show ‘ ‘the behavior or condition of a victim of sexual assault”). But here, the record does not show Dr. Paglini’s qualification to address the impact on the victim of grooming activity. He thus did not demonstrate with sufficient specificity that his formal schooling, employment experience, or practical experience qualified him to testify about grooming and its impact on the victim in this case. See Hallmark, 124 Nev. at 499, 189 P.3d at 650-51; see also NRS 50.275; Jones v. United States, 990 A.2d 970, 975, 978-80 (D.C. 2010) (former FBI agent who *865studied 400 to 500 cases of sexual abuse involving teenage victims as well as published writing in manuals on sexual abuse and the behavior of child molesters qualified); Morris v. State, 361 S.W.3d 649, 668 (Tex. Crim. App. 2011) (recognizing that law enforcement officer ‘ ‘with a significant amount of experience with child sex abuse cases may be qualified” to discuss grooming).
Although this court has not specified the requirements for admitting expert testimony about grooming, I would have preferred a more thorough record for reviewing the district court’s exercise of discretion, including the link between his expertise and the subject matter of the testimony being offered to assist the jury in this case.
Assistance
The record further fails to demonstrate that Dr. Paglini’s testimony was sufficiently relevant to have assisted the jury. See NRS 50.275 (requiring that expert testimony assist the jury to “understand the evidence or to determine a fact in issue”); Hallmark, 124 Nev. at 500, 189 P.3d at 651 (requiring that expert testimony be “relevant and the product of reliable methodology” (footnote omitted)). The majority notes that Perez’s behavior and conduct with the victim began as mildly flirtatious and escalated to the point of being overtly sexual. I agree with the majority that Perez’s actions needed no expert explanation in and of themselves as his designs for engaging in sexual conduct with the victim were evident from the escalating nature of his actions. However, I part from the majority’s conclusion that expert testimony was necessary to explain the effect of Perez’s actions on the victim.
The testimony was not of assistance because the victim could, and in fact did, explain how Perez’s conduct allayed her resistance to his abuse. The victim, who was 14 years old at the time of trial, testified about events that occurred only the year before, described how the grooming activity made her feel, and acknowledged that she developed feelings for Perez. Further, she did not resist Perez’s physical advances because of these feelings. In addition, she explained her hesitance to fully and accurately disclose the nature of Perez’s abuse. Remarkably, her resistance to disclosing the abuse turned on fear of her aunt’s reaction, not the effects of Perez’s grooming. Because the victim explained during her testimony that Perez’s conduct ingratiated himself to her and, to some extent, beguiled her, see Morris, 361 S.W.3d at 652, 667 (describing grooming behavior as “really no different from behavior that occurs in high school dating”), the expert testimony was unnecessary, see United States v. Raymond, 700 F. Supp. 2d 142, 152 (D. Me. 2010) (noting that expert testimony on motivation of child victim is not required when victim can testify about her motivations); State v. Braham, 841 P.2d 785, 790 (Wash. Ct. App. 1992) *866(“Surely, expert opinion is not necessary to explain that an adult in a ‘close relationship’ with a child will have greater opportunity to engage in the alleged sexual misconduct.”). While this court tolerates expert testimony that incidentally bolsters another witness’s testimony, see Townsend v. State, 103 Nev. 113, 118-19, 734 P.2d 705, 709 (1987) (recognizing that expert testimony may have a corroborative effect on the complaining witness’s testimony), the testimony here primarily served to augment the victim’s testimony.
As the expert testimony was not probative with regard to the victim’s actions, it became unfairly prejudicial in how it characterized Perez’s behavior. Unnecessary expert testimony carries the risk of unduly influencing the jury:
Expert testimony on a subject that is well within the bounds of a jury’s ordinary experience generally has little probative value. On the other hand, the risk of unfair prejudice is real. By appearing to put the expert’s stamp of approval on the government’s theory, such testimony might unduly influence the jury’s own assessment of the inference that is being urged.
United States v. Montas, 41 F.3d 775, 784 (1st Cir. 1994); see also Raymond, 700 F. Supp. 2d at 150 (noting that expert witness testimony about matters in the jury’s common sense “invites a toxic mixture of purported expertise and common sense”). Although expert insight into the effect of grooming behavior, i.e., the victim’s emotional dependence on the abuser, may have appeared relevant to understanding the victim’s reluctance to come forward, testimony about the defendant’s prior bad acts, which may have fostered that emotional dependence, did not explain the victim’s behavior and carried a significant risk of unfair prejudice to the defendant by characterizing his prior actions as similar to those of other sex offenders. See State v. Hansen, 743 P.2d 157, 160-61 (Or. 1987), superseded on other grounds by Or. Evidence Code R. 103, as stated in Powers v. Cheely, 771 P.2d 622, 628 n.13 (Or. 1989). Thus, where expert testimony addresses a defendant’s prior bad acts, “[cjare must be taken in order that prior acts evidence is not bundled into an official-sounding theory and coupled with expert testimony in order to increase its apparent value in demonstrating a ‘plan’ or malevolent intent by the defendant.” State v. Coleman, 276 P.3d 744, 750 (Idaho Ct. App. 2012).
Apart from his testimony about the impulsivity of adolescents due to lack of cortical function in the frontal lobes of the brain— testimony the majority correctly concludes Dr. Paglini was not qualified to give—Dr. Paglini said very little about grooming’s impact on victim behavior that, left unexplained, would confuse the jury. Rather, Dr. Paglini was asked to define grooming and then to answer a series of purported hypotheticals, such as, “You have a situation of a 13-year-old niece who had known her 33-year-old *867uncle her whole life and had seen him on a regular basis, would the following conduct over about a three and four month period potentially constitute grooming activity? First touching the niece’s foot under the table at family parties or winking at the niece.” There follows a series of hypothetical questions, each one identifying something the defendant did in relation to the victim, such as calling her, objecting to her having boyfriends, and concluding it might be grooming. Such testimony
exceeded permissible bounds when the prosecutor tailored the hypothetical questions to include facts concerning the abuse that occurred in this particular case. [It] went beyond explaining victim behavior that might be beyond the ken of a jury, and had the prejudicial effect of implying that the expert found the testimony of this particular claimant to be credible.
People v. Williams, 987 N.E.2d 260, 263 (N.Y. 2013); see State v. McCarthy, 283 P.3d 391, 394-95 (Or. App. 2012).
Here, Dr. Paglini focused on Perez’s uncharged bad (and, in some instances, perhaps innocent) acts and characterized them as motivated purely by his intent to sexually abuse his niece. The testimony carried a significant risk that the jury would “make the quick and unjustified jump from his expert testimony about behavioral patterns to guilt in a particular case that shows similar patterns.” Raymond, 700 F. Supp. 2d at 150; see also Hansen, 743 P.2d at 161 (noting that where probative value is lacking, “the danger of unfair prejudice to defendant from the unwarranted inference that, because defendant engaged in acts that sexual child abusers engage in, she, too, is a sexual child abuser is simply too great”). Thus, even if the testimony had some limited probative value, NRS 48.015, that value was substantially outweighed by the danger of unfair prejudice, NRS 48.035(1).
Considering that the State failed to elicit sufficient information regarding Dr. Paglini’s qualifications and the victim was able to articulate how Perez’s prior conduct affected her, I would conclude that the district court abused its discretion in admitting this testimony. I reiterate that I am not opposed to the use of expert testimony on grooming in all cases. It certainly becomes more relevant where the grooming activity in question is not clearly apparent or the child witness is of such an age that he or she could not plainly express how that activity affected him or her. Nevertheless, in that situation, the State must make a sufficient showing that the expert has sufficient academic or professional experience specifically related to grooming of child sexual assault victims.
Expert-witness notice
I further disagree with the majority’s conclusion that the expert-witness notice was adequate to inform the defendant of the extent *868of testimony that the State sought to elicit. NRS 174.234(2) requires pretrial disclosure of experts in cases involving gross misdemeanor or felony charges. The disclosure must, at minimum, give “[a] brief statement regarding the subject matter on which the expert witness is expected to testify and the substance of the testimony.” NRS 174.234(2)(a) (emphasis added). The State’s expert-witness disclosure designated Dr. Paglini and stated he would “testify as to grooming techniques used upon children,” nothing more. This notice was far too brief, and while it identified the subject matter of the testimony in the broadest of terms, it did not sufficiently address the substance of that testimony. As noted above, most of Dr. Paglini’s direct testimony involved his opinion of hypothetical scenarios posed by the prosecutor that mirrored the specific facts of this case. The notice did not inform Perez that the State sought Dr. Paglini’s opinion on these matters. Further, the notice did not inform the defense that Dr. Paglini had reviewed materials specific to this case, including the victim’s statements, reports, and transcripts of other hearings. Therefore, Dr. Paglini’s testimony about the specific conduct at issue in this case ambushed Perez with expert testimony he was not warned to be prepared to defend against.
Harmless error
I further conclude that the error in admitting Dr. Paglini’s testimony was not harmless. See Fields v. State, 125 Nev. 776, 784, 220 P.3d 724, 729 (2009) (reviewing erroneous admission of evidence for harmless error). In considering whether the erroneous admission of evidence had a “ ‘substantial and injurious effect or influence in determining the jury’s verdict,’ ” Tavares v. State, 117 Nev. 725, 732, 30 P.3d 1128, 1132 (2001) (quoting Kotteakos v. United States, 328 U.S. 750, 776 (1946)), this court considers ‘ ‘whether the issue of innocence or guilt is close, the quantity and character of the error, and the gravity of the crime charged.” Big Pond v. State, 101 Nev. 1, 3, 692 P.2d 1288, 1289 (1985).
This case is impacted by all three factors. First, the question of guilt or innocence is close. The testimony supporting the charges was inconsistent. The victim’s testimony was inconsistent with her initial reports to hotel security and the police. Perez’s wife, whose initial reports to hotel security and the police supported the allegations of abuse, testified consistently with Perez’s admission that he kissed the victim. No physical evidence supported the allegations. Second, the character of the error was particularly damaging in this case. Expert testimony which rationalized the inconsistencies in the victim’s testimony had a significant impact on the jury’s determination of guilt. The problem was exacerbated by the *869emphasis Dr. Paglini and the State placed on Dr. Paglini’s work conducting “risk assessments” on known sex offenders. Proceeding act by act through hypothetical questions concerning the flirtations that preceded the Las Vegas assault portrayed Perez as a sex offender, on a par with the 1,000 other convicted sex offenders of risk to the community Dr. Paglini had evaluated. But Perez was not on trial for grooming over a three to four month period in California. The charges he faced involved a single incident in a Las Vegas hotel room that occurred in the space of time it took Perez’s wife, the victim’s aunt, to take a shower in the room’s adjacent bathroom. Lastly, Perez was charged with serious sexual offenses against a minor, for which he has been sentenced to multiple life sentences, with the possibility of parole after 35 years. See NRS 200.366(3)(c); NRS 201.230(2).
Accordingly, I would reverse the judgment of conviction and remand for a new trial.