COUNCIL OF ECONOMIC ADVISERS ISSUE BRIEF

MARCH 2016

THE PATENT LITIGATION LANDSCAPE:

RECENT RESEARCH AND DEVELOPMENTS

Introduction

Innovation serves as an important source of productivity 

growth. More than one half of the growth in the United 

States’ productivity between 1948 and 2014 came from 

innovators and entrepreneurs, who worked to create 

new products or make improvements to existing 

products.1 Academic research, such as Geroski (1989) 

and Romer (1990), has long acknowledged the 

importance of innovation to economic growth. In order 

to drive productivity growth, American inventors need 

the tools and incentives to experiment, innovate, and 

commercialize their ideas.

The patent system offers one such important tool for 

inventors. The U.S. Patent and Trademark Office (USPTO) 

grants patents to inventors of innovations that meet all 

the statutory requirements, including that it exhibit both 

“novelty and non-obviousness.” Recent academic 

research has linked patent grants to beneficial firm-level 

outcomes, including productivity growth, job creation, 

and sales growth (Balasubramanian and Sivadasan 2011; 

Farre-Mensa, Hegde and Ljungqvist 2016). 

After being granted a patent, the inventor has several 

options. The inventor may choose to: (1) commercialize 

the patent and be a practicing entity (PE); (2) license or 

sell the patent to another party that will commercialize 

it; or (3) sell the patent to an intermediary that has more 

experience in securing licensing opportunities or 

enforcing patent rights (Hagiu and Yoffie 2013). This 

intermediation is sometimes performed by nonpracticing entities (NPEs). As highlighted in the 2013 

White House report “Patent Assertion and U.S. 

Innovation,”2 NPEs can therefore in some cases provide 

 1 See Chapter 5 (page 208) of the 2016 Economic Report of 

the President, available: 

https://www.whitehouse.gov/sites/default/files/docs/ER

P_2016_Chapter_5.pdf

2 Original report issued June 2013 is located here: 

https://www.whitehouse.gov/sites/default/files/docs/pa

tent_report.pdf. An addendum with additional citations 

issued March 2016 is located here: 

a valuable intermediation service for smaller companies 

and individual inventors. 

It is possible that others may infringe on the patent, and 

the patent owner can then enforce his or her patent 

rights by bringing a patent infringement lawsuit. As 

noted in the 2013 Report, it can under certain conditions 

be costly to engage in patent litigation, either as a 

plaintiff or as a defendant. Thus, for defendants, these 

high costs mean that they may prefer to settle rather 

than fight patent litigation suits that they view as being 

without merit. This possibility of obtaining a settlement, 

without the defendant challenging the merits of the 

case, in turn increases the expected value of frivolous 

litigation, thus creating additional incentives for it to 

occur. On the other hand, well-financed defendants can 

outlast entrepreneurs with fewer resources, and thus 

induce plaintiffs with meritorious cases to accept 

settlements that are favorable to the defendants. 

Balancing the incentives to innovate with incentives to 

enforce or defend against patents appropriately is a 

challenge.

An analysis of recent research conducted since the 2013 

Report, described in further detail below, suggests that a 

substantial amount of patent litigation in the United 

States, often with little substantive merit, often arises 

from certain types of NPEs called “patent assertion 

entities” (PAEs).3 Some of this research calls into 

question whether the costs imposed by PAE-initiated 

litigation are greater than the intermediation benefits 

that are provided by NPEs. Determining the extent to 

which those costs exceed these benefits could in turn 

help inform whether further changes to the patent 

landscape—whether from executive, judicial, or 

https://www.whitehouse.gov/sites/default/files/microsit

es/ostp/PatentReportAddendumMarch2016.pdf. 3 Although much of this research has been conducted 

since 2013, in many cases it relies on data that predate 

important changes to the patent litigation landscape, 

including the America Invents Act and a variety of recent 

U.S. Supreme Court decisions.
2

congressional actions—would be beneficial with respect 

to making the patent system more efficient. The issue 

brief highlights the following findings:

• Annual patent grants have increased over the past 40 

years;

• The overall number of patent litigation lawsuits 

appears to have increased over the past 40 years, 

though it is not clear how much the rate of litigation 

has increased;

• NPEs appear to be parties to an increasing 

proportion of patent litigation cases over the past 

ten years;

• Damages awarded to NPEs have been increasing, 

while damages for practicing entities (PEs) have been 

declining;

• NPEs pursue different litigation strategies than PEs; 

NPEs are more likely to litigate older patents, to 

pursue legal action in specific courts, and to target 

cash-rich firms; 

• Patent litigation by NPEs appears to have a negative 

effect on innovation, though the effect on 

entrepreneurship is less clear, and more research is 

needed.

This issue brief also highlights that over the past few 

years, several important changes have occurred in the 

patent landscape due to executive and judicial actions.4

 

In particular, the U.S. Supreme Court has handed down 

several high-profile patent law decisions on topics such 

as patent-eligible subject matter and the awarding of 

attorney’s fees. In addition, the USPTO has implemented 

new post-grant review procedures established by the 

2011 Leahy-Smith America Invents Act (AIA), providing a 

less expensive and faster way to challenge the validity of 

a patent. Finally, in December 2015, a change to the 

Federal Rules of Civil Procedure went into effect that 

affects pleadings. The effects of these many changes are 

just beginning to work their way through the patent 

litigation landscape, and in most cases are not yet 

 4 Scott Morton and Shapiro (2015) provide a useful 

overview of recent legislation and legal cases related to 

patent litigation.

measurable in the data. As a result, additional research 

on the effects of these reforms will be needed.

Patent Stock and Litigation

As indicated by Figure 1, annual patent grants have 

increased dramatically over the past 50 years, from 

approximately 50,000 to nearly 250,000 annually (left 

axis). The ratio of patents to GDP (right axis) appears to 

have decreased from a high in the 1970s to a low point 

in the late 1990s, before increasing again. Much of this 

recent growth in patenting has been in the computer 

sector, likely driven by the rise of the Internet, personal 

computers, mobile technology, and general IT 

infrastructure. More advanced applications of computer 

technology that are just beginning to come to the 

forefront and will likely continue to drive patent stock 

growth include artificial intelligence, advanced robotics, 

and big data analytics.

As indicated by Figure 2, the overall number of patent 

litigation cases (left axis) has approximately quadrupled 

over the past three decades. Research on the amount of 

patent litigation generally finds that it has increased 

(e.g., GAO 2013; Cohen, Gurun, and Kominers 2015; PWC 

2014). 

The rate of patent litigation (right axis), calculated as the 

ratio of the number of patent litigation cases to the 

number of in-force patents, increased on net from the 

1970s to mid-1990s, then fell modestly from the mid-
3

1990s to 2010, before increasing again through 2014. 

Thus, trends in the rate of patent litigation depend on the 

time frame used. These figures are similar to rates 

reported by other researchers. For example, Marco, 

Miller, and Sichelman (2015) trace patent litigation rates 

from 1971 to 2009 and report similar findings for this 

time period. 

It is notable that some of the increase in patent litigation 

came immediately prior to and after the America Invents 

Act (AIA) took effect in 2011. The reasons for the recent 

increase are unclear. The increase since 2009 may have 

been due in part to a temporary increase in false marking 

cases (PWC 2013). Part of the increase may also have 

been due to the AIA’s change in the “joinder rule” that 

had previously allowed multiple cases against different 

parties, involving a single infringed patent, to be joined 

into one lawsuit.5 The change in the joinder rule suggests 

that it may be useful to analyze litigation trends using 

other measures than the number of patent cases that 

were filed in a year. For example, Cotropia, Kesan, and 

Schwartz (2014) study lawsuits that were filed in 2010 

and 2012 and show that, while the number of filed cases 

increased from 2010 to 2012, the number of unique 

patentees and number of defendants remained about 

the same in these two years.

Finally, research suggests that some of the time series 

variation in patent litigation is explained by business 

 5 The joinder provision of AIA (35 U.S.C. § 299) imposes 

restrictions on the types of parties that can be joined in a 

single suit.

cycles, with patent litigation increasing during recessions 

(Marco, Miller, and Sichelman 2015). While our time 

series does not extend further back in time, independent 

research suggests that longer-term structural changes 

matter as well. For example, the rate of patent litigation 

was higher in the mid-nineteenth century than it is now. 

Beauchamp (2015) reports that “New York City and 

Philadelphia ... had ten times more patent suits filed in 

1850, per U.S. patent in force, than did the entire United 

States in 2013.”

NPEs, Damages, and Litigation Strategies

Patent litigation cases are brought by both nonpracticing entities (NPEs) and practicing entities (PEs). 

PEs are organizations that make, use, sell, offer for sale, 

or export, a patented product or service. NPEs are 

organizations that own patents but do not make or use 

the patented technology directly. They may (and in fact, 

often do) license the technology to be used by others. 

The NPE category includes patent assertion entities 

(PAEs) that assert infringement of a patent with the sole 

goal of generating revenues from licensing or 

settlements of litigation and may include individual 

inventors and universities who solely license patents to 

others (Lemley and Melamed 2013). These distinctions 

are not always easy to draw when categorizing plaintiffs 

in patent litigation. As a result, some studies do not 

attempt to differentiate between PAEs and other NPEs.

As Figure 3 illustrates, the share of patent litigation cases 

brought by NPEs has grown over time, from below 30 

percent of all cases in 2009 to over 60 percent in 2014 

(RPX 2014; RPX 2015).6 The majority of NPE cases are 

filed by PAEs, estimated to be 89 percent of all NPE cases 

(RPX 2015). Cohen, Gurun, and Kominers (2015) also 

show that the percent of cases brought by NPEs 

increased between 2000 and 2012. Given that the patent 

litigation rate has not changed appreciably over that 

period, this trend may represent a shift in litigation away 

from PEs to NPEs.

6 RPX is a publicly traded company (NASDAQ: RPXC) that 

provides patent risk management services, including 

insurance and market intelligence.
4

Median damages awarded to NPEs also appear to have 

increased over time and are larger than those awarded 

to PEs (PWC 2014). As indicated in Figure 4, the median 

award to PEs fell from $4.3 million during 2000 – 2009 to 

$2.5 million during 2010 – 2013, while the median award 

to NPEs increased from $7.3 million during 2005 – 2009 

to $8.5 million during 2010 – 2013. According to PWC

(2014), median damages awarded during 1995 – 2013 

were higher for PAEs and other companies than 

universities and individual inventors, although PWC does 

not provide information on how this breakdown has 

changed over time. More research is needed to 

understand the reasons for the high damages awarded 

to NPEs relative to PEs, including a better understanding 

of any timing or selection effects. For example, it is 

possible that NPEs have a higher settlement rate than 

PEs—indeed, Mazzeo, Ashtor, and Zyontz (2013) suggest 

that NPEs, and PAEs in particular, may have incentives to 

reach settlement quickly—meaning that lawsuits 

brought by NPEs that make it to a court decision are a 

highly selected set of cases. 

NPEs appear to have different litigation strategies than 

PEs. According to RPX (2015), NPEs were overwhelmingly 

likely to file suit in the Eastern District of Texas or the 

District of Delaware, and these two courts together 

accounted for 70 percent of cases filed by NPEs in 2014. 

As shown in Table 1, from 1995 – 2013, the Eastern 

District of Texas was the court with the most decisions 

involving NPEs, both in absolute number and in percent 

of decisions. This type of “forum shopping” is a notable 

feature of the current patent litigation environment. It is 

not surprising that litigants are motivated to act in this 

way; litigation success rates vary widely across district 

courts, as do damages and time to trial. The uncertainty 

around litigation costs and outcomes may lead 

defendants to settle quickly to avoid high costs or 

unfavorable decisions, even when the suit has little merit 

(Lemley and Melamed 2013).

NPEs also appear to target certain types of firms. A study 

by Cohen, Gurun, and Kominers (2015) finds that firms 

with large amounts of cash, or with a recent positive 

shock to their cash holdings, are more likely to be 

targeted by an NPE in a patent litigation suit (the authors

do not differentiate between NPEs and PAEs). In 

contrast, they find that cash has no significant effect on 

the probability of being sued by a PE. The role of cash has 

been highlighted in other research as well. Feldman and 

Frondorf (2015) conduct a survey of patent-holding firms 

that went public between 2007 and 2012. They find that 

the likelihood of being accused of patent infringement—

which includes both pre-suit allegations of infringement 

and the commencement of formal court proceedings—

increased substantially after the firm completed its initial 

public offering. 

Another litigation strategy used by some NPEs is to target 

older patents (Love 2013). According to Love (2013), 

NPEs prefer to assert their patents late in the patent 

term, when the purportedly infringing firms are likely to 

have amassed greater resources. In contrast, PEs 

generally enforce their patents at the beginning of the 

patent term when the incentives to recoup their 

substantial R&D costs are the highest. Even though they 

are NPEs, universities, and individual inventors conduct 

little late-term litigation, as they may share similar 

incentives as PEs to recoup R&D costs earlier. Cohen, 

Gurun, and Kominers (2015) also find that NPEs target 

older patents. 
5

According to Cohen, Gurun, and Kominers (2015), some 

NPEs also target firms that may have a reduced ability to 

defend themselves. They find that NPEs are more likely 

to target a firm when it has fewer lawyers and more 

ongoing non-IP related cases. The authors argue that the 

firm will be more likely to settle in such instances as it 

lacks the resources to defend itself, and this 

circumstance serves as an incentive to would-be NPE 

plaintiffs.

Innovation and Entrepreneurship

Patent litigation carries implications for investment in 

innovation. A model by Cohen, Gurun, and Kominers

(2015) shows that patent litigation by NPEs can reduce 

infringement and incentivize innovation in some cases, 

but can also lead to frivolous litigation that hurts 

innovation, in other cases. It is therefore important to 

review the empirical evidence. Recent evidence seems to 

suggest that, on net, patent litigation by NPEs hurts 

innovation in some cases, though the research on how 

NPE litigation affects entrepreneurship is quite limited. 

Scott Morton and Shapiro (2014) develop a theoretical 

model that they use to assess how patent litigation 

affects innovation. When they fit the model with existing 

data, the results suggest that, on net, NPE patent 

litigation reduces innovation (Scott Morton and Shapiro 

2015). Other empirical research generally supports this 

finding. Cohen, Gurun, and Kominers (2015) find that 

firms reduce their R&D expenditure significantly after 

losing to or settling with an NPE. Smeets(2014) finds that 

corporate R&D intensity for defendants drops following 

patent litigation for small firms that are involved in costly 

lawsuits. Galasso and Schankerman (2015) exploit the 

random assignment of judges to cases and find that 

patent invalidation results in a 50 percent decrease in 

future patenting by the patent-holder. However, they 

also find that the effect is primarily on small innovative 

firms; there is little effect on large, incumbent firms. 

There has been comparably less research on the effects 

of patent litigation on entrepreneurship. Kiebzak, Rafert, 

and Tucker (2016) investigate the link between levels of 

patent litigation and venture capital (VC) investment in 

the United States, an indicator of levels of 

entrepreneurial activity. They conclude that VC 

investment initially increases with the number of 

litigated patents, but that beyond a certain threshold, 

further increases in litigated patents are associated with 

decreased VC investment. They also find some evidence 

that a similar relationship exists between patent 

litigation and small firm entry. Chien (2015) also reports 

that patent litigation disproportionately affects smaller 

companies. However, more research is needed on the 

link between patent litigation and entrepreneurial 

activity.

Recent Developments 

There have been several recent executive and judicial 

actions that may help curtail abusive litigation going 

District

NPE Cases 

Filed (2014 

alone )

Decisions 

Involving 

NPEs

Total Identified 

Decisions

NPE Percent of 

Total Decisions 

NPE 

Success 

Rate 

Median damages 

(millions of 

dollars)

Median timeto-trial (years)

Texas Eastern 1352 50 136 37% 46% 9.1 2.21

Delaware 613 23 196 12% 35% 19.1 1.97

California Central 87 15 84 18% 33% 3.1 2.23

California Northern 83 28 149 19% 14% 8.4 2.44

New Jersey 80 6 87 7% 17% 16.6 2.71

Illinois Northern 59 33 136 24% 15% 6 3.67

Florida Middle 54 8 35 23% 63% 0.3 1.8

Florida Southern 49 13 40 33% 15% 0.4 2.5

Virginia Eastern 46 8 47 17% 25% 37.3 0.97

New York Southern (*) 31 132 23% 13% 5.6 2.88

Massachusetts (*) 14 77 18% 36% 4.2 3.58

Minnesota (*) 10 48 21% 40% 1.6 2.66

Texas Southern (*) 10 47 21% 10% 57 2.01

Texas Northern (*) 9 35 26% 56% 3.6 2.42

Table 1: District Court Patent Litigation Data, 1995-2013

Note: * indicates that RPX (2015) groups the district into its "All Others" category, which included 368 cases in 2014. 

Sources: PWC (2014); RPX (2015). 
6

forward. These developments concern patent eligibility, 

post-grant review, pleading standards, and attorney’s 

fees.

Patent Eligibility

One such area of the patent litigation landscape that has 

been substantially affected in recent years by Supreme 

Court decisions is that of patent eligibility—that is, what 

sorts of ideas or technologies can or cannot be patented. 

Recent decisions in this domain have covered three kinds 

of subject matter: “abstract ideas,” “natural 

phenomena,” and “laws of nature.” The Supreme Court 

has long held that all three are ineligible for patenting, 

and the Court’s recent decisions have clarified the 

application of these principles in the context of evolving 

technology. 

With regard to abstract ideas, it ruled in 2010 in Bilski v. 

Kappos that the concept of hedging in investments is an 

abstract idea that is not entitled to patent protection, 

even when the implementation of the idea is within a 

computer system. The Court found similarly in 2014 in 

Alice Corp. v. CLS Bank International, holding that the 

institution of intermediated settlement, which can help 

reduce settlement risk, is an abstract idea ineligible for 

patent protection. Likewise, regarding so-called “laws of 

nature,” the Court held in 2012 in Mayo Collaborative 

Service v. Prometheus Laboratories, Inc. that knowledge 

of a particular set of physiological effects of a certain 

drug constituted a non-patentable law of nature. Its 

decision the following year in Association for Molecular 

Pathology v. Myriad Genetics, Inc. also found that a 

naturally occurring DNA segment is a product of nature 

and not patent eligible (importantly, however, it made a 

distinction with and exception for synthetic DNA that 

does not occur naturally). Evidence reviewed by Scott 

Morton and Shapiro (2015) suggests that the Alice

decision has led to higher dismissal rates on the grounds 

that the patent claims cover non-patentable subject 

matter. More research on the effects of Alice and the 

other decisions is warranted, however.

 7 For more information on these changes, see 

http://www.uspto.gov/blog/director/entry/ptab_s_quick

_fixes_for and 

http://www.uspto.gov/sites/default/files/documents/Re

port_on_Implementation_of_the_AIA_September2015.p

df

Post-grant Review

In 2012, the USPTO issued rules and guidance that 

established a new trial procedure, called inter partes 

review (IPR), which is handled by the Patent Trial and 

Appeal Board (PTAB) rather than a federal court. This 

process for challenging the validity of a patent provides 

a quick, inexpensive alternative to district court 

litigation, and should help improve patent quality and 

ultimately reduce frivolous litigation.7 While it is too 

early to assess the effect of the new IPR procedure on 

patent litigation, USPTO has conducted its own research 

to better understand which patent characteristics are 

determinative of IPR petitions.8

Pleading Standards

Until recently, plaintiffs were able to file a suit over vague 

patent claims without specific allegations of 

infringement, and thus were able to demand the 

production of voluminous documentary evidence at the 

defendant’s expense until more specificity could be 

required in later filings. This old way of doing business—

which was based on what was known as the “Form 18” 

pleading requirement—was reformed a few months ago 

(as of December 1, 2015) as a result of actions taken by 

the Supreme Court and the Judicial Conference of the 

United States that modified the Federal Rules of Civil 

Procedure and Appendix of Forms. As a result of this rule 

change, patent asserters must satisfy the pleading 

standard set forth by the Supreme Court in its decisions 

in Bell Atlantic Corp. v. Twombly and Ashcroft v. Iqbal, 

under which lawsuits “must be supported by factual 

allegations.”9

 As the rule change has been in effect for 

only a few months, it remains to be seen how this change 

will affect litigation empirically.

Attorney’s Fees

In addition, until recently, it was relatively unlikely that a 

prevailing defendant in patent litigation would be able to 

recover attorney’s fees and expenses from the plaintiff. 

On April 29, 2014 the U.S. Supreme Court released two 

8 More information is available at: 

http://www.uspto.gov/sites/default/files/documents/Pat

ent%20litigation%20and%20USPTO%20trials%20201501

30.pdf

9 556 U.S. 662 (2009).
7

decisions—Octane Fitness, LLC v. ICON Health & Fitness, 

Inc. and Highmark v. Allcare Health—that clarified the 

legal standards lower courts should apply in deciding 

whether to award attorney’s fees to a prevailing 

defendant. In both cases, the Supreme Court rejected 

two standards that the Court of Appeals for the Federal 

Circuit had previously applied when determining 

whether to award attorney’s fees, each of which made it 

more difficult for prevailing parties to recover them.10 It 

is too early to assess whether these practices have 

indeed become more widespread or have deterred 

baseless litigation.

Looking Ahead

These recent developments are promising in that all of 

them should reduce the level of frivolous patent 

litigation, in theory. Post-grant review and clarifications 

of patent eligibility both have the potential to improve 

patent quality, thus reducing the frequency of frivolous 

litigation, while new pleading standards and expanded 

trial court discretion in awarding attorney’s fees to 

prevailing parties should hinder or discourage such 

litigation. Despite these changes, it will take some time 

before their effects can be discerned from official 

statistics. Moreover, further research that relies on these 

data will then be needed in order to fully determine 

whether and how these changes have affected the 

patent litigation landscape.

Conclusion

Innovation helps drive productivity growth in the United 

States. Patents are an important tool that incentivize 

invention and creativity, allowing inventors and 

companies to protect their investments and support 

their commercialization. Legal recourse such as litigation 

is likewise an important tool for inventors and other 

patent owners to protect their patents from 

infringement. However, patent litigation can also be 

used opportunistically when the cost of litigating is 

higher than the cost of settlement. In other words, 

accused infringers may decide to settle rather than bear 

 10 In Octane Fitness, the Supreme Court held that the 

Federal Circuit had too narrowly defined the 

circumstances in which a prevailing party would be eligible 

to recover its attorney’s fees. The Court also held that a 

prevailing party need not demonstrate its entitlement to 

attorney’s fees by “clear and convincing evidence” (as the 

the cost of fighting what they believe to be allegations 

without merit, and patent holders with meritorious 

claims (and limited resources) may decide to settle 

rather than bearing the costs of fully enforcing their 

patent rights.

In this issue brief, we use recent research to assess the 

state of patent litigation in the United States. The level of 

patent litigation has increased over time, but it is less 

clear that the rate of patent litigation has increased; 

depending on the time period used, the rate of patent 

litigation appears either flat or increasing. Research 

suggests that there has been a shift towards litigation by 

NPEs relative to PEs over the past decade. Those NPEs 

that are PAEs appear to favor specific litigation 

strategies, including choosing venues for their cases and 

targeting cash-rich firms or firms that are in vulnerable 

positions, among other strategies. Finally, some recent 

research suggests that NPEs’ litigation strategies can 

have a negative effect on innovation in some cases. 

Additional research is needed to understand the reasons 

for the high damages awarded to NPEs relative to PEs 

and the role that selection might play in these 

differences, if any. Additional research is also needed to 

understand how patent litigation affects 

entrepreneurship, if at all.

Many recent policy and legal changes, such as the AIA, 

recent court decisions, and executive actions, would 

appear to help curtail abusive litigation. While the effects 

of these many changes are still unfolding and more 

research is needed, the current data suggests that 

further reform—be it from further legislative, judicial or 

executive actions—may still be warranted, particularly in 

regard to the high concentration of litigation in certain 

judicial districts. Any reforms, however, should take into 

account the changes that have already occurred and are 

ongoing in the patent litigation landscape. 

Federal Circuit had held) but instead must satisfy the less 

rigorous “preponderance of the evidence” standard. In 

Highmark, the Court rejected the application of de novo

review by appellate courts of a district court’s decision on 

attorney’s fees and instead held that a district court’s fee 

decision is subject to abuse-of-discretion review.
8

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