California may be on the precipice of a seismic change in the standards governing the admissibility of expert witness testimony. While the state has not altered its requirement of admitting expert testimony so long as it is “generally accepted,” in a recent case1, the California Supreme Court rejected the testimony of a CPA/Attorney expert who utilized a market share approach to lost profit damages because the methodology had been used in complicated patent cases, antitrust cases, and unfair competition cases.” In other words, this approach was not novel.


So why did the California Supreme Court affirm the lower court’s decision not to permit the expert witness testimony? It was too speculative. Not that it wasn’t “generally accepted,” but that the results of the expert’s approach were too speculative.

While this isn’t a definitive indication that the California Supreme Court is ready to adopt the Daubert standard, it could be the start. In Daubert v. Merrell Pharmaceuticals, Inc, 505 U.S. 579, 113 S. Ct. 2786, 125 L. Ed. 2d 469, 1993, the U. S. Supreme Court applied a multifactor approach in determining whether an expert witness’s testimony was admissible. The approach required that federal district courts make a preliminary determination of whether the theory or technique has been tested, whether it has been subjected to peer review, the court must be made aware of its known or potential error rate, and whether it has attracted widespread acceptance within a relevant scientific community.

The requirements of peer review, error rate analysis and widespread acceptance are certainly more restrictive than “generally accepted.” With the case mentioned, the California Supreme Court may be ready to follow the U.S. Supreme Court’s lead and increase the minimum requirements in qualifying experts and their theories.

Which begs the question: how do you determine whether your expert witness and his/her theories will be admissible? Your best bet is to rely upon the resume and expertise of your expert to inform you of the current state of affairs within his field of expertise. And the most comforting solution is a simple one: use tried and true experts witnesses; experts who have been “field tested” in court.

When you interview an expert witness, make sure that your expert knows the difference between generally acceptable and widespread acceptance. For though the standards haven’t been changed, you don’t want your case to be the one that everyone cites as the opinion that changed the standards. Be ahead of the curve. Meet the higher standards before they’re adopted, not after.

Start using expert witnesses who can already withstand the approaching higher standards of appellate review that seem to be just over the horizon.

By: Ian Heller, J.D.

Case referenced: (Case No. S191500, 11/26/12),