How is compliance with the best mode requirement determined?
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.
Determining compliance with the best mode requirement involves a two-prong inquiry, as outlined in MPEP 2165:
- Subjective Inquiry: Determine if the inventor possessed a best mode for practicing the invention at the time of filing. This focuses on the inventor’s state of mind.
- Objective Inquiry: If a best mode existed, determine if the written description adequately disclosed it for a person skilled in the art to practice. This focuses on the scope of the claimed invention and the level of skill in the art.
The MPEP cites Eli Lilly & Co. v. Barr Labs. Inc. to support this two-prong approach:
“Determining compliance with the best mode requirement requires a two-prong inquiry. First, it must be determined whether, at the time the application was filed, the inventor possessed a best mode for practicing the invention. This is a subjective inquiry which focuses on the inventor’s state of mind at the time of filing. Second, if the inventor did possess a best mode, it must be determined whether the written description disclosed the best mode such that a person skilled in the art could practice it.“