Nathan’s team members serve as consultants and expert witnesses, providing insightful analyses of class certification, liability, and damages in class- or collective-action matters across a wide variety of industries.

Our talented and respected advisors assess risk in support of settlement negotiations and calculate the relative value of proposed settlements in light of that risk assessment. With a proactive, disciplined approach, we analyze the common impact and feasibility of assessing damages class-wide, investigate facts relevant to the claims of the proposed class, perform statistical analysis on the issue of liability, and evaluate the merits of planned complaints. Our expert witnesses provide well-supported testimony in deposition and at trial on common impact and the feasibility of assessing class-wide liability and damages.


Russell W. Mangum III

Russell W. Mangum III

Senior Vice President
+1 949 955 9025
Jonathan Schwartz Nathan Associates

Jonathan Schwartz

Senior Vice President
+1 703 516 7760
Chen Song

Chen Song

Senior Vice President
+1 424-888-5995 LA +1 949 474 4938 OC


Our team combines analytical rigor, versatility, and a collaborative approach to meet the complex challenges of class certification, whether from the plaintiff or the defense side. Recent trends in the legal environment have raised the bar for class certification in the U.S. At the same time, class action and competition law in Europe and other overseas jurisdictions has been evolving rapidly. In these matters, it is more important than ever for counsel to work closely with experts in competition economics and/or damages throughout the class certification process in both the U.S. and Europe. Our team has the necessary experience and insight to help counsel meet these growing challenges.


In class action or collective action employment matters, our experts provide clients with expert testimony and consulting in class action discrimination disputes, and in class action or collective action wage and hour claims. We assist clients through all stages of these disputes and claims, including class certification analysis, liability determination, economic damages calculation, risk assessment for mediation, and data management and analysis during claims administration. This work includes applying econometric techniques to examine pattern or practice claims regarding companies’ employment practices, conducting pay-equity and labor-market studies, and performing statistical analyses of complex data in connection with claims of unpaid overtime resulting from off-the-clock work, missed meal and/or rest break time, and misclassifications.

Employment & Labor

Our experts have extensive experience with issues relating to product liability & mass tort litigation. We advise companies or other parties with an interest in product liability and mass torts on the possible magnitude of those losses and on issues relating to insurance gap shortfalls, cash flow concerns, estimates informing financial reporting, potential tort settlements and the value of future unasserted claims. Our experience includes liability arising from sources including asbestos, beryllium, lead paint, latex gloves, pharmaceuticals, medical devices, mercury, silica, coal mine dust, silicone breast implants, and welding rods.

Product Liability & Mass Torts

Our experts apply our class action and class certification methodologies to a multiplicity of product liability and false advertising matters. We have consulted on matters that include alleged harm arising from genetically modified commodity agricultural products, the effects of allegedly misleading product package statement related to clinical testing, and the effects of an allegedly misleading menu and store window statement related the non-GMO nature of food at a fast-casual restaurant chain.

Product Liability and False Advertising

Our in-house Ph.D. economists and certified accounting and finance professionals, joined by our outside network of academic and industry experts, bring a unique combination of analytical insight, technical knowledge, and practical experience to bear on securities class action matters. We have the necessary experience to assist counsel with class certification, liability, and class-action damages issues that can arise in securities cases, including those filed under Rule 10b-5 and/or Section 11. Our experience also covers corporate-governance and director-liability issues that arise in securities litigation, such as issues that arise as a consequence of SOX-404. Our clients value our ability to produce rigorous, independent analysis appropriate for settlement or litigated outcomes.

Securities & Financial Services