The Propriety of Allowing Rebuttal Experts

Despite the lack of consistency in reported cases considering whether to allow rebuttal experts, there is a general agreement on at least one proposition: Where an expert has been properly disclosed prior to trial, it is almost always an abuse of discretion for the court to deny the plaintiff an opportunity to present a rebuttal expert, at least where the proffered testimony is non-cumulative. One state appellate court has even recognized rebuttal testimony as a “matter of right” where new facts are introduced during the opponent's case. Teller v. Schepens, 518 N.E.2d 868, 870 (Mass. App. Ct. 1988). On the other hand, no such right exists to present rebuttal evidence for the sole purpose of supporting a party's affirmative case. Id. Accordingly, most courts agree that the purpose of rebuttal expert testimony is to address new matters brought during the defense's case-in-chief rather than to “bolster the plaintiff's case-in-chief.” Id. at 871. In the absence of timely disclosure, however, courts have applied various factors in reaching conclusions regarding the admissibility of rebuttal experts.