The Effect of Blinded Experts on Juror Verdicts


  • Christopher T. Robertson,

  • David V. Yokum

  • Thanks to Gregory Schwartz, Aaron Kesselheim, and Tom Mauet for serving as actors and consultants; to James Greiner, George Kimball Smith, and anonymous reviewers for the Conference on Empirical Legal Studies and Journal of Empirical Legal Studies for commenting on drafts, and to Germar Townsend, Tess Gemberling, Carol Ward, Judy Parker, Barbara Lopez, and Bert Sky for excellent research and administrative support.

Address correspondence to Christopher T. Robertson, James E. Rogers College of Law, the University of Arizona, PO Box 210176, Tucson, AZ 85721; email:


“Blind expertise” has been proposed as an institutional solution to the problem of bias in expert witness testimony in litigation (Robertson 2010). At the request of a litigant, an intermediary selects a qualified expert and pays the expert to review a case without knowing which side requested the opinion. This article reports an experiment that tests the hypothesis that, compared to traditional experts, such “blinded experts” will be more persuasive to jurors. A national sample of mock jurors (N = 275) watched an online video of a staged medical malpractice trial, including testimony from two medical experts, one of whom (or neither, in the control condition) was randomly assigned to be a blind expert. We also manipulated whether the judge provided a special jury instruction explaining the blinding concept. Descriptively, the data suggest juror reluctance to impose liability. Despite an experimental design that included negligent medical care, only 46 percent of the jurors found negligence in the control condition, which represents the status quo. Blind experts, testifying on either side, were perceived as significantly more credible, and were more highly persuasive, in that they doubled (or halved) the odds of a favorable verdict, and increased (or decreased) simulated damages awards by over $100,000. The increased damages award appears to be due to jurors hedging their damages awards, which interacted with the blind expert as a driver of certainty. Use of a blind expert may be a rational strategy for litigants, even without judicial intervention in the form of special jury instructions or otherwise.