How Hard Is It, Really, to Prove Derivation?

Dec 2003 – Article
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.