Back in March, in Monolithic Power Systems, Inc. v. O2 Micro Int'l Ltd., the Federal Circuit Court of Appeals held that the district court's appointment of a nonpartisan expert under Federal Rule of Evidence 706 was not an abuse of discretion. That's the good news, and it's apparently better news than I initially thought, because I.P. commentators seem to think that this was a novel event.
The bad news is that Judge Randall Rader added dictum that will undoubtedly limit the future appointment of nonpartisan experts in cases that may wind up before the Federal Circuit on appeal: "The predicaments inherent in court appointment of an independent expert and revelations to the jury about the expert's neutral status trouble this court to some extent. Courts and commentators alike have remarked that Rule 706 should be invoked only in rare and compelling circumstances." Judge Rader than cited exactly one court, a district court opinion from 1993, and one commentator, Wright's Federal Practice and Procedure.
In fact, for well over one hundred years, evidence scholars (including me, and see citations in this article) and other commentators have (with some exceptions, of course) been arguing for much greater use of court-appointed experts, and have expressed frustration at judges' consistent reluctance to do so, whether under their inherent powers (before Rule 706), or under Rule 706 and state equivalents.
Rule 706 itself says nothing about "rare" or "compelling" circumstances, but simply: "The court may on its own motion or on the motion of any party enter an order to show cause why expert witnesses should not be appointed, and may request the parties to submit nominations. The court may appoint any expert witnesses agreed upon by the parties, and may appoint expert witnesses of its own selection."
As far as courts are concerned, in Daubert v. Merrell Dow Pharmaceuticals, the Supreme Court stated: "Throughout, a judge assessing a proffer of expert scientific testimony under Rule 702 should also be mindful of other applicable rules.... Rule 706 allows the court at its discretion to procure the assistance of an expert of its own choosing." In the follow-up case of Joiner v. General Electric Co., Justice Breyer, concurring, strongly advocated that courts take advantage of their Rule 706 power to appoint experts. One of the sources he cited was a book by Judge Jack Weinstein, author of the one opinion relied upon by Judge Rader.
In short, neither the text of Rule 706, nor the opinions of evidence scholars, and certainly not precedent emanating from the highest court in the land suggests that use of Rule 706 is limited to rare and compelling circumstances.