This is often the case because, while both partiesâ€™ filing dates are known at the start of an interference and each partyâ€™s own actual conception and reduction-to-practice dates should be reasonably ascertainable by that party, each party may know little or nothing about its opponentâ€™s conception and reduction-to-practice dates when it files its preliminary motions. It is also often the case that when a party assesses possible motions to attack the validity (patentability) of its opponentâ€™s claims, it will realise that its own claims are vulnerable to the same challenges. In other words, a party may not be able to challenge the patentability of its opponentâ€™s claims successfully without bringing its own claims down as well. And each party must decide what to do before knowing what motions, if any, its opponent is going to bring.Regardless of this possiblility of mutual destruction, the authors write that interferences proceedings can provide certain advantages:
There is also the possibility of obtaining de novo review via litigation in the federal courts.
Unlike infringement litigation in the federal district courts, during an interference there is no presumption of validity that must be overcome in order to invalidate an opponentâ€™s patent claims. Interferences are tried at the outset before the PTO, before administrative law judges who have substantial familiarity with legal and technical issues important to patent disputes.