David P. Herrick's practice focuses on scientific expert testimony. Herrick has pursued Daubert objections to "junk science" expert testimony in a variety of mass tort contexts, including the asbestos, benzene, silica, fen/phen diet drug, and silicone breast implant litigations. Herrick had what one Texas Lawyer article characterized as some "stunning successes" on behalf of his clients.  Herrick won the first Daubert hearings in both the breast implant and fen/phen litigations and obtained the first Daubert appellate victories in both the asbestos and breast implant litigations. 

Herrick has been responsible for locating and working with expert witnesses in order to develop the "science" themes to be used at trial and on appeal. As a result of this experience, Herrick is a recognized expert on Daubert and scientific evidence and has spoken on the issue at professional forums throughout the United States. Herrick testified about Daubert as an expert witness before the Texas House Committee on Judiciary & Civil Jurisprudence.

Herrick also has an active appellate practice. In addition to handling cases on appeal, Herrick is retained to assist trial counsel with complex legal issues arising during trial in order to preserve or avoid appellate complaints. Herrick has been called upon to handle dispositive motions such as summary judgment, Daubert objections, mandamus actions, and motions to recuse and/or disqualify. Herrick also handles traditional appellate functions during trial such as preparation of the jury charge and the post-verdict process.