There are many good reasons to review prior art. For patent applications, we routinely recommend a review of prior art before preparing a new patent application. Why? First, if a prior art reference is found that anticipates your invention, you can avoid the expense of prosecuting the application. Second, because what you and your patent attorney do not know about the prior art can negatively affect the value and scope of a patent’s protection. Knowing the prior art enables us to draft claims that can often avoid amendments. Why is that important? U.S. Supreme Court decisions on claim interpretation have made it very important to draft claims in a certain manner to avoid narrowing the scope of a patent’s protection. Amending claims to obtain allowance of a patent may result in a reduction of a patent’s scope.

For parties evaluating a third party’s patent rights, a review of the prior art can help a client to design around a particular patent or series of patents. A business competitor’s earnest attempt to design around a patent is often considered in patent litigation as a factor in deciding that the patent infringement was not willful. A review of the prior art can also help a client decide whether to take a license. A review of prior art also can uncover references that were not considered in the prosecution of a patent application. If these references are material, they may call into question the validity of a patent.

A patent is presumed to be valid, and a challenger must provide clear and convincing evidence to prevail on an invalidity defense. In patent litigation, however, it is very common for a patent infringement defendant to expend significant resources to scour the earth for printed publications to cast doubt on the validity of a patent. Consequently, a patent owner or plaintiff sometimes conducts his own prior art review to test the strength of his case before initiating patent litigation. A prior art review can help a patent owner and counsel determine the prospects for success in the ultimate litigation.