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Stylized Facts of Patent Litigation. Jean O. Lanjouw and Mark Schankerman. THE DATA. I. Data source to identify litigated patents: Patent History CD-ROM, Derwent based on information from the US PTO 5,452 cases for the period 1975-91 involving 3,887 patents Linked To:
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Stylized Facts of Patent Litigation Jean O. Lanjouw and Mark Schankerman
THE DATA I. Data source to identify litigated patents: Patent History CD-ROM, Derwent based on information from the US PTO 5,452 cases for the period 1975-91 involving 3,887 patents Linked To: II. Comprehensive U.S. Federal Court Data: Inter-university Consortium for Political and Social Research 22% of Cases Reported (1977-9) 85% of Cases Reported (1985-7) III. “Matched Sample” 3,887 patents drawn from population controlling for IPC and cohort
CHARACTERISTICS • Number of Claims • Set of all 4-digit IPC sub-class assignments • Nationality of Patent Owner • Domestic U.S.; Non-Japanese Foreign; Japanese • Based on assignee if there is one, otherwise the inventor • Corporate versus Individual Ownership • Identified by whether there is an assignee • (Patent Scan CD-ROM, Micro Patent) • Backward and Forward Citations with their 4-digit IPC sub-class assignments
Table 1: Litigation Rates and Composition Panel A: Filed Cases per 1,000 Patents, 1980-1984 By Technology Group and Ownership TotalDomesticForeign Drugs & Health 20.1 26.6 6.5 Chemical 5.4 6.1 1.4 Electronic 9.6 12.7 3.3 Mechanical 11.8 20.1 3.4 Other 15.2 23.4 9.9 Total 10.7 16.4 3.5
Other Points Related to Table 1 • Josh Lerner estimates 60 cases per 1000 in biotech • Individuals have a 16% higher probability of litigation than corporate owners, except for Japanese owners. There, individuals have a rate 3 times that of corporations
Table 2: Forward Citations Domestic Non-Japanese Japanese Foreign Matched Litigated Matched Litigated Matched Litigated Mean 6.3 12.0 4.8 11.5 5.8 12.0 Citations (0.16) (0.24) (0.19) (0.78) (0.32) (1.55)
Similarity Index: • Measure of how much the IPC classes of a patent’s forward or backward citation overlap with those of the patent itself. • Backward vs. Forward Citation? • Citation by Others vs. Citation by Self?
Table 3: Similarity of CitationLitigated (L) vs. Matched (M) Patents • Thus, a patent more likely to be involved in a suit: • if there are others patenting related innovations in the same technology area. • If it is the base of a cumulative chain where later patents are held by the same owner.
Table 7 Characteristics Associated with the Probability of a Suit Infringement Suits Challenge Suits ParametersMarginal EffectsParametersMarginal Effects (1) (2) (3) (4) Log Claims 0.405** 0.136** 0.433** 0.058** (.030) (.010) (.050) (.007) FWD Cites/Claim 0.256** 0.081** 0.230** 0.029** (.019) (.006) (.027) (.003) FWD Cites/Clm^2 -0.0083** -0.005** (.0011) (.001) BWD Cites/Claim -0.033-0.010 -0.043-0.005 (.023) (.007) (.040) (.005) BWD Cites/CLM^2 0.0012 0.003 (.0011) (.002) NO4IPC -0.062* -0.021* -0.052-0.007 (.036) (.012) (.057) (.008)
SIMFWD 0.278** 0.093** 0.129 0.017 (.087) (.029) (.144) (.019) SIMFWD*CORP 0.203** 0.162** 0.223 0.047** (.103) (.020) (.170) (.013) FWDSELF 0.674** 0.226** 0.585** 0.078** (.106) (.036) (.165) (.022) BWDSELF -1.015**-0.341** -0.936**-0.125** (.173) (.058) (.307) (.041) DINDOWN -1.419** 0.103** -2.320** 0.022 (.126) (.024) (.205) (.019) FINDOWN -2.321**-0.214** -2.911**-0.059** (.158) (.024) (.250) (.014) JINDOWN -2.305**-0.195** NE NE (.349) (.071) DCORPOWN -1.562** 0.195** -2.466**0.060** (.123) (.016) (.200) (.013) FCORPOWN -2.321**-0.181** -2.963**-0.050** (.129) (.016) (.209) (.011) JCORPOWN -2.893**-0.287** -3.510** -0.084** (.156) (.015) (.266) (.008)
Table 8Estimated Litigation Probabilities for Corporate U.S. Patentees Sample patent with maximum litigation probability in, Drugs & Health (17 Claims, 132 Citations): 27.6% Chemicals (65 Claims, 164 Citations): 3.5% Electronic ( 4 Claims, 48 Citations): 9.1% Mechanical ( 2 Claims, 39 Citations): 12.8%
Conclusions Related to the Design and Administration of the Patent System • Likelihood of a suit varies markedly with the characteristics of a patent and its owner, and • For some types the rate of litigation is high • Uncertainty about what is patentable appears to play a role
It appears that individuals are at a disadvantage relative to corporate patentees, which supports related evidence: Smaller biotech companies tend to avoid doing R&D in same technology areas as large firms They rely more heavily on trade secrets vs. patents (Lerner) Larger firms tend to request preliminary injunctions when confronting smaller defendants (Lanjouw and Lerner) • Institutional design to lower costs - particularly for smaller firms • Improvement in the ability to price patent litigation insurance