Legal Malpractice and the Arbitrator's Affidavit. Mason, Ketterman & Cawood had an interesting idea. When sued for malpractice relating to its representation of a woman in a Dalkon Shield-related arbitration, it got the arbitrator to provide an affidavit to the effect that none of their alleged mistakes would have changed the decision. The District Court granted summary judgment to the firm on the ground that, even if the firm had been negligent in its representation, the negligence was not the proximate cause of the injury, the loss before the arbitrator.

The Second Circuit held that the arbitrator's affidavit was inadmissible and its use in the summary judgment motion was prejudicial to the plaintiff. It is well settled law that testimony revealing the deliberative thought processes of judges, juries or arbitrators is inadmissible. Admission of the affidavit put the plaintiff in an impossible spot: she could not rebut the thought processes of the arbitrator. Hence, the Court vacated the decision to the extent it granted summary judgment on the issue of liability.

The Court did affirm the decision to the extent that it ruled in favor of the law firm on its counterclaim for the costs and expenses of the arbitration.

The decision in Rubens v. Mason can be found here.