The “Daubert” standard is a rule of evidence regarding the admissibility of expert witnesses’ testimony during United States federal legal proceedings, and litigation in many states. Pursuant to this standard, a party may raise a Daubert motion, which is a special case of motion in limine raised before or during trial to exclude the presentation of unqualified evidence to the jury.

The Daubert trilogy refers to the three United States Supreme Court cases that articulated the Daubert standard. Daubert v. Merrell Dow Pharmaceuticals, held in 1993 that Rule 702 of the Federal Rules of Evidence did not incorporate the Frye “general acceptance” test as a basis for assessing the admissibility of scientific expert testimony, but that the rule incorporated a flexible reliability standard instead. General Electric Co. v. Joiner held that a district court judge may exclude expert testimony when there are gaps between the evidence relied on by an expert and his conclusion, and that an abuse-of-discretion standard of review is the proper standard for appellate courts to use in reviewing a trial court’s decision of whether it should admit expert testimony and Kumho Tire Co. v. Carmichael held in 1999 that the judge’s gatekeeping function identified in Daubert applies to all expert testimony, including that which is non-scientific.

And here is how the Daubert standard works in litigation. Reuters Health reports that federal judge in Philadelphia dismissed more than 300 lawsuits against Pfizer Inc alleging that its antidepressant Zoloft caused birth defects in children born to women who took the drug while pregnant.

The decision from U.S. District Judge Cynthia Rufe in the Eastern District of Pennsylvania said that plaintiffs had not produced enough evidence to show a plausible scientific link between the drug and birth defects, following several previous decisions that excluded testimony from key expert witnesses for plaintiffs.

“The court recognizes that the final scientific verdict as to whether Zoloft can cause birth defects may not be delivered for many years,” Rufe wrote. “Nevertheless, plaintiffs chose when to file their cases, and the court concludes that for the plaintiffs who have continued to pursue their claims, the litigation gates must be closed.”

The ruling affects more than 300 lawsuits against Pfizer consolidated before Rufe in federal court.

A Pfizer spokeswoman, Neha Wadhwa, said the decision “affirms that plaintiffs have failed to produce any reliable scientific evidence demonstrating that Zoloft causes the injuries they alleged.” Dianne Nast, a lead lawyer for the plaintiffs, did not immediately return a call for comment. Pfizer had previously prevailed in two trials involving Zoloft birth-defect claims in state courts in Philadelphia and Missouri.

California does not use the Daubert standard, It adheres to the more liberal “Frye” general acceptance test. Indeed, the court of appeal in the unpublished case of Star Insurance Company v WCAB and Maria Rosa Tavares specifically rejected the Daubert standard this January in workers’ compensation cases. This explains why it is easier to win cases on weak science in California that would not likely succeed in federal courts or states that have adopted the Daubert rule.