Only 26% of patent holders win infringement cases, though that figure rises to 60.7% if the case gets to trial and 63.9% if it is decided by a judge, rather than a jury, according to a study of all 2008-2009 US patent cases. The results were very similar to a study conducted by the same author 16 years ago.
"Patentee win rates are virtually unchanged," and decisions on patent invalidity are "only slightly changed, despite the rise of [patent trolls], which now represent a majority of cases," Mark Lemley, the Stanford law professor who conducted those studies, said in a discussion at the symposium. "Despite enormous changes in 20 years, from the perspective of the litigation outcomes, things don't look very different."
Patent holders face many challenges to having their work found valid, Lemley's paper said.
The results point to a state of equilibrium in the patent system, he argued. Over the long haul, patent holders should win as often as they lose if all things were equal, but in some ways, the legal system gives advantages to accused infringers.
"The nature of patent litigation requires patentees to win every issue before the court," Lemley wrote in the paper. "A patentee who defeats five of six invalidity challenges, only to lose the sixth, [still] loses the case."
IP lawyers said at the event that, despite the poor odds, patent holders file infringement suits for many reasons. Some sue in hopes of a big payday or the impact the suit might have on other would-be infringers.
Using a regression analysis of his data, Lemley also found:
- Foreign inventers were much more likely to win but less likely to sue.
- Piling on multiple patents seemed to have a positive effect for patent holders.
- The older the patent, the more likely it was to be found invalid.
- There are no significant predictors of non-infringement.
- The Eastern District of Texas remains the one most likely to rule for the patentee (45% of the time)
- The Central District of California remains the one least likely to rule for the patentee (5% of the time).
- Biotech and software industries tend to win their cases least often (8% and 13%, respectively).
- The chemical industry is the most likely to win its cases (53%), and the electronics industry falls in the middle (31%).
Next page: Patents, not prizes