Copying in Patent Law

Patent law is virtually alone in intellectual property (IP) in punishingindependent development. To infringe a copyright or trade secret,defendants must copy the protected IP from the plaintiff, directly orindirectly. But patent infringement requires only that the defendant'sproduct falls within the scope of the patent claims. Not only doesn't thedefendant need to intend to infringe, but the defendant may be entirelyunaware of the patent or the patentee and still face liability.Nonetheless, copying does play a role in some subsidiary patent doctrines.For example, the question of whether patent damages should be set in orderto deter infringement depends critically on whether infringers are in factaware they are infringing, or at least that they are using the plaintiff'stechnology. Copying - or at least intent to infringe - is also an elementof claims for indirect infringement. The definition of "willfulinfringement" also turns on the question of culpability, at least in thepopular understanding of that term. More significantly, the rhetoric ofpatent law (and of IP law more generally) often seems to presuppose thatdefendants in patent cases are in fact engaged in copying. Similarly, theoutcome of public policy debates over patent reform may well turn on theperception of patent infringers as either bad actors or as innocentbusinesspeople who accidentally ran afoul of a patent.Unfortunately, no one seems to know whether patent infringement defendantsare in fact unscrupulous copyists or independent developers. In this paper,we seek to answer that question. Because copying is not an element of anypatent cause of action, courts do not normally make explicit findings as towhether defendants have copied. Instead, we turn to a variety of proxies totry to identify the subset of cases in which copying is alleged or proven.We look both at the allegations made in a random sample of complaints andat the treatment of copying in recent reported decisions. We find that asurprisingly small percentage of patent cases involve even allegations ofcopying, much less proof of copying. Copying in patent law seems to be theexception, not the rule.