How does the USPTO handle prior art rejections when operability is questioned?

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 USPTO handles prior art rejections where operability is questioned as follows:

• The examiner must provide a reasonable basis to question the operability of the prior art.
• If operability is questioned, the burden shifts to the applicant to provide rebuttal evidence.
• The prior art is presumed to be operable unless proven otherwise.

As stated in MPEP 2121.01: “Even if a reference discloses an inoperative device, it is prior art for all that it teaches.” This means that even if a device in prior art doesn’t work as described, it can still be used as a reference for other teachings it contains.