Patent Litigation and the Internet

62 Pages Posted: 22 Jan 2012  

John R. Allison

University of Texas - McCombs School of Business

Emerson H. Tiller

Northwestern University - Pritzker School of Law

Samantha Zyontz

Massachusetts Institute of Technology (MIT) - Sloan School of Management

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Date Written: January 20, 2012


Patent infringement litigation has not only increased dramatically in frequency over the past few decades, but also has also seen striking growth in both stakes and cost. Although a relatively rich literature has added much to our understanding of the nature, causes, and consequences of patent litigation during the past two decades, many interesting questions remain inadequately addressed. The nuances of and trends in patent litigation in different technology fields and industries, for example, are still understudied. Litigation of patents on new technologies has likewise received a dearth of attention. Here we seek to help begin filling these gaps by empirically analyzing the phenomenon in a very particular context: the litigation of Internet patents. In particular, we study litigation of patents on Internet business processes issued during the first few years in which such patents were granted, and determine whether it differs in meaningful ways from litigation of patents in other fields.

Patents on methods of doing business on the Internet (Internet patents) have been the subject of intense debate and criticism for a number of years. Indeed, since 1998, when the Court of Appeals for the Federal Circuit held that there was no per se exclusion of these Internet-implemented methods from the realm of patentable subject matter, many have questioned the wisdom of the decision and sought to have its result altered. In addition to the issue of subject matter eligibility for patenting, critics have questioned whether the U.S. Patent and Trademark Office (PTO) has improvidently granted patents on Internet processes that appear at first glance to be obvious, thus failing one of the key requirements for patentability. The importance of the Internet as a rapidly growing commercial platform combined with concerns for an open and free Internet added to the intensity of these debates.

Despite the importance of these debates, there has been relatively little empirical study of Internet patents, and no study of the increasing litigation in which they have been involved. In one of the few studies of the patents themselves, Allison and Tiller analyzed the quality of Internet patents by comparing them to other kinds of patents. They built a data set of 1,093 Internet-implemented process patents and compared many of their characteristics with those of a randomly selected set of 1,000 contemporaneously issued patents from the general population of patents (non-Internet patents, or NIPs). Their purpose was to test empirically the merits of the many criticisms of these patents, all of which had been made without the support of any data. Measuring a number of characteristics that previous research had associated with patent quality and private economic value, such as the total number of claims and prior art references, as well as several other characteristics first employed by the authors, the study found that Internet patents appeared to be of higher average quality and value than the average patent.

Researchers in economics and law have compiled evidence to support a link between the economic value of patents to their owners (private patent value) and litigation propensity. In 2004 Allison, Lemley, Moore, and Trunkey (ALMT) conducted the most comprehensive comparison yet made of litigated and unlitigated patents. Measuring a number of patent characteristics that had been linked to litigation propensity and private economic value, as well as some characteristics not previously considered but that logically might suggest value and a greater likelihood of litigation, the authors found that litigated patents were a completely different breed than those that had not been involved in litigation. With a high degree of significance, the authors found that litigated patents, compared with unlitigated ones, contained more claims and more references to prior U.S. patents, foreign patents, and other kinds of publications (“nonpatent prior art”), and were cited more often as prior art by subsequent patents (i.e., they had more “forward citations”). They were disproportionately represented in some technology areas and in some industries. They were also much more likely to have originally been issued to individuals and small businesses, and to be owned by domestic rather than foreign entities. Further, they had spent much more time in “prosecution” (examination within the PTO) from their original filing dates than unlitigated patents, primarily as a result of patent applicants having invested more in continuing applications leading to the generation of multiple patents on closely related inventions — a patent portfolio that can have greater value than the sum of its parts.

Allison and Tiller’s findings revealed that Internet patents, at least those issued during the formative years of digital commerce, possessed value-indicating characteristics very similar to those of the litigated patents subsequently studied by ALMT. Given that these characteristics suggest not only private value but also litigation propensity, the next logical questions are whether these Internet patents later experienced unusually high rates of litigation, and how these patents fared in court compared with other patents. The current study contributes to the empirical literature on patent infringement litigation by comparing litigation rates and outcomes for early Internet patents with those for a large comparison set of contemporaneously issued NIPs. Delving more deeply, we further investigate litigation rates and outcomes for two subgroups of Internet patents identified by Allison and Tiller — those covering relatively broad Internet business “models” and those covering narrower Internet business “techniques.” The important difference between these subgroups is that the claim language in those Internet patents classified as business models is usually broader — that is, more general — than in the other subgroup. More general claim language tends to increase the universe of potential infringers, thus creating at least a possibility of higher litigation rates and perhaps greater win rates.

Using both univariate comparisons and multiple regression techniques, we find primarily that: (1) Internet patents and their two subtypes were litigated at a far higher rate than NIPs — they were between 7.5 and 9.5 times more likely to end up in infringement litigation, depending on the model we used. (2) Within the category of Internet patents, those on business models were litigated at a significantly higher rate than those on business techniques. (3) Across both Internet patents and NIPs, patents issued to small entities, especially individuals and small businesses, were much more likely to be litigated than those issued to large entities; (4) Patents of all kinds with more independent claims were significantly more likely to be litigated than those with fewer independent claims. (5) Including both Internet patents and NIPs, litigated patents received many more forward citations — citations received from later patents — than did unlitigated patents. (6) Patents issued to foreign entities were significantly less likely to be litigated than patents issued to U.S. entities. (7) The more time that an application for an Internet patent or NIP had spent in the PTO prior to issuance, the more likely it was that the patent granted from that application was to be involved in infringement litigation. (8) There was no difference in the ages of Internet patents and NIPs when they became the subject of litigation — both kinds were about 4.5 years old; (9) Once patent infringement litigation was initiated, the owners of litigated Internet patents were significantly more likely to settle before judgment than the owners of litigated NIPs (especially when probable settlements were taken into account along with obvious settlements, which we believe is the more accurate metric). (10) Across both sets of patents, the larger the number of potential infringers involved in a case (defendants in infringement actions and plaintiffs in declaratory judgment actions), the less likely the case was to settle. (11) Internet patents and NIPs went to trial at about the same rate. (12) When failing to settle, the owners of NIPs won on the merits at a significantly higher rate than did owners of Internet patents — although the win rate for NIP owners was quite low at around 16%, the win rate of Internet patents was even lower by a substantial margin. This finding did not hold up in regression analysis, however; when the effects of other variables were taken into account in a logistic regression analysis, there was no significant difference in the win rate for accused infringers between Internet patents and NIPs. Accused infringers did win more often when Internet patents were asserted against them than win they defended against NIP complaints, but the relatively small number of observations prevented the difference from being statistically significant. (13) Surprisingly, owners of both kinds of patents were significantly more likely to win as the number of inventors on the patents increased. (14) The longer that applications for Internet patents and NIPs had spent in the PTO before issuance, the less likely accused infringers were to win. (15) Accused infringers were less likely to win on the merits when the Internet patents or NIPs asserted against them had been litigated previously. (16) Across both sets of patents, the larger the number of potential infringers involved in a case, the more likely these potential infringers were to win a judgment on the merits. That is, the more infringement defendants per case, the more likely these defendants were to win. (17) There was no difference between the different types of patents in the percentage of cases that were terminated for procedural reasons. We also discuss a few other findings of interest.

These findings raise some intriguing questions for further research: (1) How does litigation of patents on other relatively new technology fields compares with litigation of patents from the general population, the latter consisting predominantly of patents on more mature technologies? (2) How might litigation of patents on different technologies early in their maturation periods compare to each other? (3) Are patents on young technologies likely to be stronger and more valuable on average because there is less relevant prior art to require the narrowing of patent claim language or because applicants perceive greater potential innovation importance and are willing to invest more in the patenting enterprise, thus leading to more litigation? (4) Do patents on young technologies generate more uncertainty because of their newness, contributing to more contention? (5) The Internet patents in our data set, whether litigated or not, showed many of the same internal characteristics as patents in all fields that wind up in litigation. Is the same true of patents in other emerging fields of patenting activity such as flash memory, smart phones, nanotechnology, and others?

We also posit other questions for future research that are not limited to the context of new patent fields. For instance, our current study found that the average number of defendants per case significantly decreased the odds of settlement and increased the odds of a win on the merits by defendants (the term “defendants” here referring to “potential infringers” whether they are actually defendants in infringement cases or plaintiffs in declaratory judgment actions who then become infringement counterclaim defendants). This confirms recent findings by Allison, Lemley, & Walker, and may indicate that such a result is generalizable. Thus, an investigation empirically probing the wisdom of patent owners’ litigation strategies when deciding whether to sue multiple alleged infringers in a single lawsuit or in several different ones may bear interesting fruit in other contexts. In addition, given our finding of significantly different litigation rates for patents on online business models and online business techniques, the former clearly appearing to have broader claims, another research question is whether one might devise methods to create empirical estimates of patent claims’ breadth for use in better predicting which patents companies should fear when they assess how much freedom of action they have to innovate in a given field. The role of so-called “non-practicing entities” (NPEs) also deserves more research attention. These are companies that do not make or sell products and thus are not vulnerable to patent infringement counterclaims, as are product companies that sue for infringement. NPEs consequently may be less reluctant to sue. There is a significant but imperfect correlation between the fact that a patent was originally issued to a small entity and the identity of a patent infringement plaintiff as an NPE, and in the current study one of our findings is that patents granted to small entities, especially to individuals and small businesses, are much more likely to be litigated. Thus it may be worthwhile to investigate the NPE/product company question in future studies of patent litigation over other types of patents.

Keywords: Patent Law, Litigation, Patent Infringement Litigation, Technology, Innovation

Suggested Citation

Allison, John R. and Tiller, Emerson H. and Zyontz, Samantha, Patent Litigation and the Internet (January 20, 2012). Available at SSRN: or

John R. Allison (Contact Author)

University of Texas - McCombs School of Business ( email )

CBA 5.202
University of Texas at Austin
Austin, TX 78712
United States

Emerson H. Tiller

Northwestern University - Pritzker School of Law ( email )

375 E. Chicago Ave
Chicago, IL 60611
United States

Samantha Zyontz

Massachusetts Institute of Technology (MIT) - Sloan School of Management ( email )

77 Massachusetts Ave.
Cambridge, MA 02142
United States

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