Interference proceeding
An interference proceeding, also known as a priority contest, is an inter partes proceeding to determine the priority issues of multiple patent applications. It is a proceeding unique to the patent law of the United States. Unlike in most other countries, which have long had a first-to-file system, until the enactment of the Leahy-Smith America Invents Act (AIA) in 2011, the United States operated under a first-to-invent. The interference proceeding determines which of several patent applications had been made by the first inventor. The AIA switched the US to a first-to-file  regime effective March 16, 2013, and interferences apply only to patent applications with an effective filing date prior to that change. Definition. An interference proceeding is an administrative proceeding conducted by a panel of administrative patent judges (administrative law judges sitting on the Board of Patent Appeals and Interferences) of the United States Patent and Trademark Office (USPTO) to determine which applicant is not entitled to the patent if both claimed the same invention in: A panel, composed of judges on the Board of Patent Appeals and Interferences, a quasi-judicial body in the USPTO, hears an interference contest. Its  final judgment adjudicating one party as an earlier inventor is called a priority award, or simply an award. Appeals from this tribunal are heard before either the United States Court of Appeals for the Federal Circuit or the United States District Court for the District of Columbia. See , . Parties. At least two parties are involved in an interference proceeding: the inventor(s) or applicant(s) who filed an earlier patent application are called the "senior party", and the other inventor(s) or applicant(s) are called the "junior party". Both parties can be referred as "contestants", but that term is currently more likely to  be used to describe the junior party. Presumptions. Presumptions are stated in 37 C.F.R. 41.207(a): Leahy-Smith America Invents Act. On September 16, 2011, President Obama signed the Leahy-Smith America Invents Act into law. Part of the Act changed the U.S. patent system from a first-to-invent system to a first-to-file system. As such, interference proceedings for any patent application with an effective filing date on or after March 16, 2013, were eliminated from U.S. patent law. Derivation proceedings are replacing interference proceedings in the patent statutes, but the dispute surrounding a derivation proceeding is unrelated  to that of an interference proceeding.