What should examiners consider when performing an interference search for applications with different effective filing dates?

This page is an FAQ based on guidance from the Manual of Patent Examining Procedure. It is provided as guidance, with links to the ground truth sources. This is information only: it is not legal advice.

Patent examiners must be particularly careful when conducting interference searches for applications that may have claims with different effective filing dates. The MPEP 2304.01(a) provides guidance on this matter:

“Examiners are reminded that some applications, such as continuation-in-part applications, may contain claims entitled to different effective filing dates (see MPEP §§ 2133.01 and 2152.01), and that each effective filing date should be considered when performing the interference search.”

This means that examiners must consider the possibility of interfering subject matter based on multiple dates, which may affect the scope of prior art and potential interferences.