Legal Memorandum: Testimony Requiring a Rebuttal Report in US, UT, and CO

Issue: What do the federal courts say constitutes rebuttal testimony requiring a rebuttal report?

The stated issue involves the nature of proper rebuttal evidence as well as the expert report requirements mandated by Fed.R.Civ.P. 26(a).  Thus, before directly addressing the stated issue, it is helpful to discuss, briefly, federal law regarding (1) the definition of rebuttal evidence and, (2), the report requirements for opinion testimony involving treating physicians, generally.

“[T]he case law especially in the 10th Circuit is rather sparse with regard to exactly what constitutes proper rebuttal evidence.”  Ashike v Mullen Crane and Transport, Inc., No. 12-11 (D. Utah Jan.8, 2014).  In general, “[r]ebuttal evidence is evidence which attempts to ‘disprove or contradict’ the evidence to which it is contrasted.”  Richie v. Mullin 417 F.3d 1117, 1138 (10th Cir. 2005) (citing Black’s Law Dictionary 579 (7th ed.1999)).  Generally, “the determination of what constitutes proper rebuttal evidence [lies] within the sound discretion of the [district court].”  Hickok v. G.D. Searle & Co., 496 F.2d 444, 447 (10th Cir.1974).

On the other hand, not just any evidence that contradicts another party’s evidence in some way may be properly characterized as “rebuttal evidence.”  The purpose and function of rebuttal evidence is to address “new and unforeseen“ evidence presented by the adverse party.  See Faigin v. Kelly, 184 F.3d 67, 85 (1st Cir. 1999) (“The principal objective of rebuttal is to permit a litigant to counter new, unforeseen facts brought out in the other side’s case.”); Marmo v. Tyson Fresh Meats, Inc., 457 F.3d 748, 759, 760 (8th Cir. 2006) (same).  […]