The “clear and convincing standard” lets bad patents through the cracks.

An issued patent is presumed valid. Courts require a firm that challenges a patent to prove its invalidity by “clear and convincing evidence.” This standard appears unjustified. A plethora of presumptions and procedures tip the scales in favor of the ultimate issuance of a patent, once an application is filed. In addition, as many have noted, the PTO is underfunded, and PTO patent examiners all too often do not have sufficient time to evaluate patent applications fully. These circumstances suggest that an overly strong presumption of a patent’s validity is inappropriate. Rather, courts should require only a “preponderance of the evidence” to rebut the presumption of validity.

The PTO works under a number of disadvantages that can impede its ability to reduce the issuance of questionable patents. Perhaps most important, the courts have interpreted the patent statute to require the PTO to grant a patent application unless the PTO can establish that the claimed invention does not meet one or more of the patentability criteria. Once an application is filed, the claimed invention is effectively presumed to warrant a patent unless the PTO can prove otherwise.

The PTO’s procedures to evaluate patent applications seem inadequate to handle this burden. The patent prosecution process involves only the applicant and the PTO. A patent examiner conducts searches of the relevant prior art,27 a focal point of the examination process, with only the applicant’s submissions for assistance. The patent applicant has a duty of candor to the PTO, but that duty does not require an applicant to search for prior art beyond that about which the applicant already knows.28 If the patent applicant makes assertions or files documentary evidence regarding certain facts, the PTO does not have facilities with which to test the accuracy or reliability of such information.

Moreover, presumptions in PTO rules tend to favor the issuance of a patent. For example, “[i]f the examiner does not produce a prima facie case [of obviousness], the applicant is under no obligation to submit evidence of nonobviousness.”29 Similarly, “[o]ffice personnel . . . must treat as true a statement of fact made by an applicant in relation to [the asserted usefulness of the invention], unless countervailing evidence can be provided that shows that one of ordinary skill in the art would have a legitimate basis to doubt the credibility of such a statement.”30 Likewise, “[t]here is a strong presumption that an adequate written description of the claimed invention is present when the application is filed.”31

The PTO’s resources also appear inadequate to allow efficient and accurate screening of questionable patent applications. Patent applications have doubled in the last twelve years and are increasing at about 10% per year.32 With 27 yearly applications approximating 300,000,they arrive at the rate of about 1,000 each working day.33 A corps of some 3,000 examiners must deal with the flood of filings.34 Hearings participants estimated that patent examiners have from 8 to 25 hours to read and understand each application, search for prior art, evaluate patentability, communicate with the applicant, work out necessary revisions, and reach and write up conclusions. Many found these time constraints troubling.35 Hearings participants unanimously held the view that the PTO does not receive sufficient funding for its responsibilities.

Finally, the PTO grants patents based only on the “preponderance of the evidence.” This standard applies in the context of an underlying presumption that the patent should be granted unless the PTO can prove otherwise. It does not seem sensible to treat an issued patent as though it had met some higher standard of patentability.

Defenders of the application of the “clear and convincing” evidence standard urged that a finding of patent validity by a neutral government agency using a knowledgeable examiner justifies placing a heavy burden on those who challenge a patent’s validity. We disagree. Presumptions and procedures that favor the grant of a patent application, combined with the limited resources available to the PTO, counsel against requiring “clear and convincing evidence” to overturn that presumption. We believe the “clear and convincing evidence” burden can undermine the ability of the court system to weed out questionable patents,36 and therefore we recommend that legislation be enacted to amend the burden to a “preponderance of the evidence.”