Fifty top lawyers of major corporations, including Big Pharma, Big Insurance and Big Tech, are urging the federal court system to clarify a rule of evidence that sets standards on expert testimony.

The lawyers, primarily chief legal officers and general counsel, sent a joint letter Monday to the Advisory Committee on Evidence Rules, which is looking at how federal courts address expert testimony and is exploring whether to amend the procedural rule, known as Rule 702.

Expert testimony is required when cases involve "scientific, technical or specialized knowledge" that falls outside the common experience of the jury. Problems arise for companies in cases such as the recent Roundup and talc cancer cases, where federal agencies ruled the products safe but plaintiffs' experts were allowed to testify otherwise.

The letter signers include Lucy Fato, executive vice president and general counsel of American International Group Inc.; Kent Walker, senior vice president, global affairs and chief legal officer of Google; Dev Stahlkopf, vice president and general counsel of Microsoft Corp.; and Doug Lankler, executive vice president and general counsel of Pfizer Inc. Several signers could not immediately be reached for comment.

The letter states, "Our experience indicates that adherence to Rule 702's standards for the admission of opinion testimony is far from acceptable."

Too often, the chief legal officers wrote, courts are "allowing juries a role in deciding whether an expert's opinions have the requisite scientific support."

The letter continues: "Confusion about the court's role in assessing foundational requirements results in the admission of unreliable opinion testimony that misleads juries, undermines civil justice, and erodes our stakeholders' confidence in the courts."

The letter also complains that some courts refer to a presumption of admissibility, which it calls "a mischaracterization that inverts the proponent's burden to establish the admissibility of expert testimony."

The top lawyers urged the committee to amend Rule 702 to clarify that:

• The proponent of an expert's testimony is responsible for establishing its admissibility.
• The proponent's responsibility requires demonstrating the sufficiency of the basis and reliability of the expert's methodology and its application.
• An expert shall not declare confidence in an opinion that is not derived from sufficient facts and reliable methods.

Rule 702 was drafted to give effect to the 1993 U.S. Supreme Court decision in Daubert v. Merrell Dow Pharmaceuticals, requiring standards for expert testimony. Amy Wilson, general counsel of Dow Inc., is one of the signers of the letter. As is Scott Partridge, general counsel of the U.S. operations of Bayer Corp., which now owns the oft-sued weedkiller Roundup.

Many of the chief legal officers are members of the Lawyers for Civil Justice, a nonprofit trade association made up of corporate counsel and their defense attorneys. The group, which focuses on the fairness, costs and efficiencies of the civil justice system, made the letter public.

Alex Dahl, general counsel of the Lawyers for Civil Justice, told Corporate Counsel that the timing of the letter was critical. The advisory committee has been studying Rule 702 for about two years and is "intending to decide whether to move forward with an amendment at the next meeting on May 8," Dahl explained.

He said the list of signers reflects a great diversity of industries. That such a diverse group would come together in one letter, he added, "demonstrates there is a pervasive problem with the standard."

Dahl said, "The standard is not being uniformly administered, and the courts are not executing their gatekeeping role as the rule envisioned."