Do applicant patent citations matter?

Patent law both imposes a duty on patent applicants to submit relevant prior art to the PTO and assumes that examiners use this information to determine an application's patentability. In this paper, we examine the validity of these assumptions by studying the use made of applicant-submitted prior art by delving into the actual prosecution process in over a thousand different cases. We find that patent examiners rarely use applicant-submitted art in their rejections to narrow patents, relying almost exclusively on prior art they find themselves. Our findings have implications for a number of important legal and policy disputes, including initiatives to improve patent quality and the strong presumption of validity the law grants issued patents-a presumption that makes patents more difficult to challenge in court. (C) 2013 Published by Elsevier B.V.