It is among the worst news a litigator can hear—privileged documents were produced to the other side by mistake. And, in the world today, where even relatively small cases routinely involve massive amounts of electronically stored data, it happens a lot. As Magistrate Judge Andrew J. Peck commented recently, “[i]n virtually every production, no matter what search method is used or how carefully a manual privilege review is conducted, some privileged material will be inadvertently produced.”¹

Fortunately, there are a number of strategies available to help protect against inadvertent disclosure in the first place. But before we get to that, it is worth discussing Rule 502 of the Federal Rules of Evidence, which was enacted in 2008 to address the escalating costs of protecting against waiver of the attorney-client privilege and the work product protection.²

Subsections (a) and (b) of the Rule already have made a significant impact in bringing about more cost-effective privilege review. The fear of broad subject matter waiver due to inadvertent disclosure of privileged or protected information—which was often the reason that lawyers put eyes on every page to be produced—has been eliminated. Rule 502(a) limits subject matter waiver to instances of intentional disclosure of privileged or protected material that creates unfairness to the adversary. According to subsection (a), in the context of a voluntary disclosure that is made in a federal proceeding (or to a federal office or agency) that waives the attorney-client privilege or work-product protection, that waiver will extend to an undisclosed communication or information in a federal or state proceeding³ only if “(1) the waiver was intentional, (2) the disclosed and undisclosed communication or information concern the same subject matter, and (3) they ought in fairness to be considered together.”⁴ In short, the rule limits subject matter waiver only to those “unusual situations in which fairness requires a further disclosure of related, protected information in order to prevent a selective and misleading presentation of evidence to the disadvantage of the adversary.”⁵