In mass tort litigation, the plaintiff’s treating physician is a critically important witness. Experienced trial lawyers know that juries listen to plaintiffs’ treating physicians, often more closely than to paid experts or even to the plaintiffs themselves. For this reason, a treating physician’s testimony about causation can be decisive. Yet, the rule governing advanced disclosure of treaters’ opinions, Federal Rule of Civil Procedure 26, has never neatly defined when or how much must be disclosed about these witnesses.
Courts and litigants have struggled to draw the line between “treating” physicians, who are not required to submit detailed disclosures under Rule 26, and experts “retained and specially employed” to provide causation opinions. While treaters are rarely paid and thus “employed” to testify on behalf of their patients, arriving at an opinion on causation of any injury is not necessarily part of a physician’s ordinary treatment and observation of a patient.