What is inequitable conduct, and when does it come up?

What is the governing test?

In Therasense v. Becton, Dickinson, the en banc Federal Circuit required separate proof of materiality and specific deceptive intent. For an omitted reference, materiality generally asks whether the Patent Office would have allowed the claim had it known of the information. The opinion recognizes an exception for affirmative egregious misconduct, such as an unmistakably false affidavit.

Can intent be inferred from a mistake?

Negligence, even gross negligence, is not the specific intent that Therasense requires. Materiality cannot substitute for intent. When intent is inferred from circumstances, deceptive intent must be the single most reasonable inference from the evidence under the opinion's clear-and-convincing standard.

What should an investigation focus on?

Identify what was submitted or withheld, who knew what, when they knew it, and the evidence supporting the inference. Separate a patentability argument from an accusation of deception. A disagreement with the examiner or discovery of a stronger reference does not itself answer the intent question.