The "Hired Gun" As An Expert Witness

Reversing medical malpractice judgment for the defendants based on trial court error in excluding "the plaintiffs' lone expert witness at trial" under FRE 702 after concluding that the proffered witness was “biased in favor of plaintiffs in medical malpractice cases” (testifying "exclusively for plaintiffs during the past year") and that this bias rendered his testimony excludable, in Cruz-Vazquez v. Mennonite General Hosp., Inc., 613 F.3d 54 (1st Cir. July 26, 2010) (No. 09-1758)

One of the challenges in the "gatekeeping" role for the admission of expert evidence under FRE 702 current system of Daubert is the so-called problem of the "hired gun." These are witnesses whose livelihood involves testifying for one sice in court. In general, the courts appear to have focused on examining the soundness of the specialized knowledge applied by the expert witness, rather than examining the general pattern or context of the witness's activities outside of the case. Witness bias may normally be explored on cross-examination for the jury to consider. In reversing the trial court's exclusion of the proffered expert, the First circuit acknowledged that expert bias alone did not prevent the expert from presenting his reliable expert opinion.

In the case, plaintiffs Cruz-Vazquez alleged that the defendant hospital and medical staff were liable for the premature birth and death, two days later, of their daughter. In presenting their case, the plaintiffs needed to "introduce evidence on causation and the standard of care" through the use of expert witnesses under the forum state's malpractice law. Cruz-Vazquez, __ F.3d at __ (citing Pagés-Ramírez v. Ramírez-González, 605 F.3d 109, 113-17 (1st Cir. 2010) (listing elements of medical malpractice in Puerto Rico)). The plaintiffs hoped to satisfy this prerequisite by offering the expert testimony of Dr. Ramirez, who had done extensive work in "pelvic surgery and gynecology while still treating obstetrics patients." Dr. Ramirez had "served as an expert witness in approximately 150 medical malpractice cases in the past ten years." However, the circumstances of the witness's practice revealed that his most recent work had been primarily for plaintiffs because defense attorneys had not consulted him on any cases. He explained that defendants are reluctant to hire experts who have testified for plaintiffs in medical malpractice actions." The circuit noted that of all the qualifications the witness was claimed to have, the trial judge seemed most preoccupied in his Daubert screening with an inherent "bias" of the witness, rather than whether his opinion reflected FRE 702's requisite reliability. It was this focus that would ultimately lead the trial judge to error when he excluded the plaintiff's expert witness. Cruz-Vazquez, __ F.3d at __.

The trial court excluded the plaintiff's expert, citing a fear that the witness had a pro-plaintiff disposition. The trial judge concluded that this bias meant that that the witness would fail to "provide impartial diagnoses" and therefore reliable scientific evidence. According to the circuit:

The district court cited as the basis for excluding Dr. Ramírez's testimony aspects of his work that are typically established through cross-examination of an expert witness at trial in an effort to discredit his or her testimony. The court's reasoning had nothing to do with the scientific validity of the opinion that Dr. Ramírez proposed to offer or the principles that underlie it. Yet, the Supreme Court has emphasized that the “overarching subject” of the trial court's inquiry when assessing proposed expert testimony “is the scientific validity—and thus the evidentiary relevance and reliability—of the principles that underlie a proposed submission.” By excluding Dr. Ramírez's testimony due to its own determination that Dr. Ramírez would be a biased witness on the grounds cited, the district court abused its discretion.
Cruz-Vazquez, __ F.3d at __ (citing Daubert v. Merrell Dow Pharmaceuticals, Inc., 509 U.S. 579, 594–95 (1993)).

In failing to admit the experts testimony, according to the circuit, the trial judge mistakenly focused on "the potential bias of an expert witness, as distinguished from his or her specialized training or knowledge or the validity of the scientific underpinning for the expert's opinion." The matter of bias was a matter "properly left to the jury” to decide and it was an error for the trial judge to dismiss the case after having decided the witness was biased. The First Circuit cited several cases that it had resolved in the past to provide insight into the division of labor between the trier of fact and the trier of law. These cases included:

  • United States v. Carbone, 798 F.2d 21, 25 (1st Cir. 1986) (noting that any expert witness's bias is a matter "properly left to the jury")
  • Sailor Inc. F/V v. City of Rockland, 428 F.3d 348, 354 (1st Cir. 2005) (noting an expert remains "subject to being discredited, both because of his patent self-interest and because both of the other experts had arrived at lower figures" and "the jury was free to weigh the credentials of the witnesses and the cogency of the bases given for their opinions").
  • Den Norske Bank AS v. First Nat'l Bank of Boston, 75 F.3d 49, 58 (1st Cir. 1996) (questions such as “bias, and the weight of the evidence” are “matters for the factfinder” )

The First Circuit clarified that bias is appropriately considered by the jury: "considerations such as an expert witness's pecuniary interest in the outcome of a case, or his status as an expert witness only for one side of an issue, or the extent to which a doctor currently sees patients, go to the probative weight of testimony, not its admissibility." Cruz-Vazquez, __ F.3d at __. The First Circuit carefully distinguished between an expert witness's testimony and the "reliability" of that testimony:
Dr. Ramírez's “specialized knowledge,” namely his medical training and experience in the field of obstetrics and gynecology and whether it would “assist the trier better to understand a fact in issue,” were the appropriate field of inquiry for the district court when it performed its gatekeeping function and evaluated him as a prospective expert. Instead, the district court deviated from that field of inquiry when it made findings that Dr. Ramírez gave testimony exclusively for plaintiffs during the past year, that he is paid to give lectures on medical malpractice and EMTALA, and that he might testify irresponsibly due to a lack of board certification, and then excluded his testimony on the basis of bias. In so doing, the district court invaded the province of the jury and exceeded its discretion.
Cruz-Vazquez, __ F.3d at __ (citing Pagés-Ramírez , 605 F.3d at 116 (“[T]he Rules of Evidence require that the judge admit expert testimony relevant to the disposition of the case when it will assist the trier of fact in understanding a fact in issue and rests on a reliable foundation.”).


Federal Rules of Evidence