Understanding Antedating Of A Prior Art Reference For A Patent

The Federal Circuit's decision in ATI Technologies ULC v. Iancu (April 11, 2019) highlights the proper standard to use in evaluating whether a claimed invention was reduced to practice before the effective date of a prior art reference. This evaluation is important because under 37 CFR 1.131 (Rule 131) for patents and patent applications being evaluated under pre-AIA (America Invents Act) guidelines, a reference that would otherwise qualify as prior art under 35 U.S.C. § 102(e) can be eliminated as prior art ("antedated") if the claimed invention is shown to have been invented before the reference's effective date. Establishing invention for antedating purposes involves showing that the invention was conceived or was reduced to practice before the reference's effective date.  The ATI decision focuses on actual reduction to practice, as there was no dispute that conception occurred before the relevant reference's effective date or that constructive reduction to practice