Rush, C.J.
This case presents an issue of first impression for this Court: may a party use evidence of an expert witness’s professional disciplinary history to challenge the expert’s credibility? Here, an expert–doctor testified that the plaintiff suffered permanent injury from an auto accident. And the defendant was not permitted to introduce evidence that the expert’s medical license had previously been on probation or evidence of the reasons underlying the expert’s past professional discipline.
Today, we hold that both types of evidence—an expert witness’s professional-licensure status and the reasons for professional discipline— may be admissible to challenge the expert’s credibility. Under the facts of this case, the trial court abused its discretion when it excluded evidence that the expert–doctor’s medical license had been on probation—though the error was harmless. And the trial court properly excluded evidence of the reasons for the doctor’s professional discipline, as that evidence was inadmissible under certain evidentiary rules. We thus affirm the jury’s verdict in the plaintiff’s favor.
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I. Evidence of both an expert witness’s professional licensure status and the reasons for professional discipline may be admissible to impeach that expert’s credibility.
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Both types of professional disciplinary history—limitations on professional licenses and the reasons underlying professional discipline— may be relevant to an expert’s credibility. And an expert’s credibility goes to the weight a jury assigns to that witness’s testimony. That weight, in turn, may directly affect the outcome of the case. After all, the trial court allows expert testimony only if it will help the jury “to understand the evidence” presented or “to determine a fact in issue.” Evid. R. 702(a).
So when a testifying expert has been subject to professional discipline, both an expert’s professional licensure status and the reasons for professional discipline may be admissible to impeach that expert’s credibility. But the evidence’s admissibility is subject to statutory restrictions and specific rules of evidence.
We now turn to whether the trial court abused its discretion when it excluded both types of evidence about Dr. Paschall’s licensure history.
II. The trial court abused its discretion when it excluded evidence of Dr. Paschall’s licensure probation, but it properly excluded evidence of the reasons for the doctor’s past professional discipline.
Here, the trial court excluded two types of evidence relating to Dr. Paschall’s professional disciplinary history—evidence that his license had been on probation previously and evidence of the reasons for his past professional discipline. As explained below, the court should have admitted the former, but it properly excluded the latter.
A. Evidence of the doctor’s past licensure status was relevant and had significant probative value.
In excluding evidence about Dr. Paschall’s past licensure probation, the trial court reasoned that the evidence lacked relevance because the doctor’s license was in good standing at the time of trial. But that ruling was an abuse of discretion. Evidence of the licensure probation was admissible to impeach the doctor because it was relevant to his credibility and its probative value outweighed any prejudicial effect. See Evid. R. 401, 402, 403.
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B. Evidence of the reasons for the doctor’s past professional discipline was barred by specific evidentiary rules.
Tunstall also tried to impeach Dr. Paschall’s testimony with evidence of the reasons for his professional discipline. These reasons included two prior misdemeanor convictions and two other acts of misconduct. Because this evidence was inadmissible for impeachment under certain evidentiary rules, the trial court properly excluded it.
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III. Excluding evidence of Dr. Paschall’s licensure probation was harmless error.
Tunstall argues that excluding evidence of Dr. Paschall’s licensure probation was reversible error, not harmless error, because it “depriv[ed] the jury of the opportunity to accurately assess [his] credibility in the face of contrary expert evidence.” Manning disagrees.
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On this record, we conclude that the trial court’s error was harmless for two reasons. First, even without the excluded evidence, Tunstall throughout trial methodically attacked Dr. Paschall’s credibility and his diagnosis of Manning’s condition. Second, Manning presented substantial and consistent testimony about how her injury has had a significant, permanent impact on her life.
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Conclusion
We hold that an expert witness’s professional licensure status and the reasons for professional discipline may be admissible to impeach that expert’s credibility. The trial court abused its discretion here by excluding evidence that Dr. Paschall’s medical license had previously been on probation. But because we find that error was harmless, we affirm the jury’s verdict.
David, Massa, and Goff, JJ., concur. Slaughter, J., dissents with separate opinion.
Slaughter, J., dissenting.
I agree that the trial court abused its discretion in excluding evidence of Dr. Paschall’s past licensure status. This evidence was relevant to his credibility as a medical expert and had significant probative value. But its exclusion was not harmless. I would reverse the trial court’s judgment for Manning and remand for a new damages trial.
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