After 1993 amendments to the Federal Rules of Civil Procedure, the vast majority of courts have found that opinion work product shared with a testifying expert must be produced. However, there is still a split.
In Simon Property Group L.P. v. mySimon, Inc., 194 F.R.D. 644, 647 (S.D. Ind. 2000), the court explained that “an attorney should not be permitted to give a testifying expert witness a detailed ‘road-map’ for the desired testimony without also giving the opposing party an opportunity to discover that ‘map’ and to cross-examine the expert about its effect on the expert’s opinions in the case.”
On the other hand, Estate of Chopper v. R.J. Reynolds Tobacco Co., 195 F.R.D. 648, 651 (N.D. Iowa 2000) held that “such opinion work product has nearly absolute immunity from discovery” even if shared with a testifying expert.
The differing positions taken by courts on the waiver effect of sharing opinion work product with a testifying expert can obviously have a dramatic effect in litigation. Lawyers must know what approach has been taken by the courts in which they are litigating.