How do examiners balance expected and unexpected results in patent applications?

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 carefully balance expected and unexpected results when evaluating patent applications. The MPEP 716.02(c) provides guidance on this process:

‘Where the unexpected properties of a claimed invention are not shown to have a significance equal to or greater than the expected properties, the evidence of unexpected properties may not be sufficient to rebut the evidence of obviousness.’

This means that examiners should:

• Assess the significance of both expected and unexpected results
• Compare the relative importance of these results
• Determine if the unexpected properties outweigh the expected ones
• Consider whether the evidence of unexpected results is sufficient to overcome obviousness rejections

The balance of these factors plays a crucial role in the overall patentability determination.