What Is The Burden of Proof When Practicing Before The Board of Patent Appeals?

MARK TERRY, ESQ.

In Ex parte Hochsmann, the Board of Patent Appeals and Interferences addressed the burden an appellant carries when arguing that a patent examiner made an error. The appeal concerned a chemical process involving salt crystals and whether the prior art disclosed the claimed crystal.

The Board weighed the examiner’s evidence of obviousness against the applicant’s countervailing evidence and arguments. It concluded that the claimed procedure would have been obvious by a preponderance of the evidence.

A preponderance of the evidence means that a proposition is more likely true than not. It is often described as a balance of probabilities or a showing greater than fifty percent.

Lessons learned: To reverse an examiner before the Board, the applicant must present evidence and argument that outweigh the examiner’s position. Although the formal threshold is only slightly more persuasive, a clear and substantial showing is the safer approach.