The Outsized Role of Experts in MDL Proceedings
Multi-district litigation consolidates hundreds or thousands of related cases before a single federal judge for pretrial proceedings. The experts who testify in bellwether trials effectively set the evidentiary framework for thousands of cases that may never go to trial individually.
Recent MDL proceedings demonstrate a consistent pattern: the side with more credible, better-credentialed expert witnesses tends to achieve better outcomes at both the Daubert gatekeeping stage and at trial.
Daubert as a Strategic Battlefield
In MDL proceedings, Daubert challenges have become increasingly sophisticated. Courts are scrutinizing not just qualifications but methodological rigor, reliability of underlying data, and whether testimony fits the specific case facts.
The social media MDL provides a recent illustration. In January 2026, the court allowed ten of eleven proposed experts to testify. This outcome rewarded experts whose opinions were grounded in peer-reviewed research and established clinical frameworks.
Practical Guidance for Expert Retention in MDLs
First, retain early. In active MDLs, the pool of top-tier experts shrinks rapidly as both sides compete for the most qualified individuals.
Second, invest in preparation. MDL experts face more intensive cross-examination than their counterparts in individual cases.
Third, coordinate across the expert team. A coordinated expert strategy is far more persuasive than a collection of isolated opinions.