How does the MPEP address the burden of proof in priority disputes?

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.

The MPEP 2304.02(c) addresses the burden of proof in priority disputes by stating:

“The burden of proof is on a party seeking the benefit of the filing date of an earlier application.”

This means that:

• The party claiming priority has the responsibility to demonstrate their entitlement to the earlier filing date.
• They must provide sufficient evidence to show that the earlier application supports the claims in question.
• The evidence must be clear and convincing to establish the right to priority.

If the party fails to meet this burden, they may not be granted the benefit of the earlier filing date, which could impact the patentability of their invention in light of intervening prior art.