The vast majority of courts require testifying experts to produce all of the material they create in that role, as well as all materials they receive from the party hiring them (even if the work product protection would otherwise cover those materials). Very few courts have dealt with material testifying experts create after they supply their expert’s report.
In FTC v. Lane Labs-USA, Inc., Civ. A. No. 00-CV-3174 (DMC), 2008 U.S. Dist. LEXIS 64776 (D.N.J. Aug. 25, 2008) (unpublished opinion), the FTC sought the production of an e-mail defendant Lane Labs’ testifying expert prepared one year after submitting his report on the issue before the FTC. The court pointed to Federal Rule of Civil Procedure 26(a)(2)(B), which requires testifying experts to disclose “‘the data or other information considered by the witness'” in forming an opinion. Id. at *3. The court noted that the testifying expert’s e-mail amounted to “a reaction to the report of the FTC’s expert,” rather than as a basis for his own opinion. Id. at *7. The court rejected the FTC’s efforts to obtain the e-mail, noting that “if a party was entitled to update discovery about what an expert thought about the other expert’s testimony, the process would never end.” Id. at *8.
Although litigants should not count on every court taking this position, it should come as some comfort to know that courts occasionally apply common sense to this aspect of the work product doctrine.