The Presumption of Validity in Patent Litigation: An Experimental Study

In this project, we are experimentally testing the importance of burdens of proof in determining the validity of a patent in litigation. The genesis of these experiments is the Supreme Court decision in Microsoft Corp. v. i4i Limited P'ship, 131 S. Ct. 2238 (2011). In i4i, the Court rejected Microsoft's claim that a jury need only be persuaded by a preponderance of the evidence to find a patent invalid, at least when the evidence before the factfinder regarding invalidity was not considered by the PTO during the examination process. Instead, it reaffirmed that an invalidity defense must be proven by clear and convincing evidence. But the Court also concluded that if the party challenging a patent's validity relied on evidence not previously considered by the PTO, then the jury should be instructed that this burden "may be easier to sustain." Id. at 2251.