Proving Peeler Diligence is Unnecessarily Difficult -- and Unnecessarily Costly ¹

By Charles L. Gholz and Kenneth D. Wilcox ^{2, 3}

Introduction

“Classical” diligence is diligence from just prior to the other side’s “entry into the field” (whether that is its filing date or the date of its conception) until your client’s reduction to practice  (whether actual or constructive).⁴  The standards for classical diligence are quite high.⁵  Basically, the inventor(s) or someone working on his, her, or their behalf either has to have been working on reducing the invention to practice (either actually or constructively) pretty much full time or the owner of the invention has to have one of a very small number of acceptable excuses for non-activity.⁶

“Peeler” diligence, so called after Peeler v. Miller, 535 F.2d 647, 190 USPQ 117 (CCPA 1976) (Rich, J.), is diligence from your client’s own actual reduction to practice to its own constructive reduction to practice.  The standards for Peeler diligence are quite low.  That is because, in terms of the statute, Peeler diligence is the absence of suppression or concealment.⁷  It doesn’t take much su...