How Hard Is It, Really, to Prove Derivation?Dec 2003 – Intellectual Property Today, Vol. 10, No. 12 at page 18
The CCPA and the Federal Circuit have stated that an interferent that alleges derivation need only prove its allegation by a preponderance of the evidence. However, statements from BPAI have occasionally suggested that, while it gives lip service to the courts’ language, in practice it requires derivation to be proved by a higher standard.