Patents aren’t ironclad property rights, but a probabilistic roll of the dice- strengthening patent protection necessarily involves assessment of patent quality and examination.

First, patents must be recognized as not being ironclad property rights but rather probabilistic rights. If patents offered perfect protection against any imitation, there would be no doubt about the best protection regime. Lemley and Shapiro (2005) qualify the uncertain intellectual property rights in a suggestive way: "A patent does not confer upon its owner the right to exclude a potential imitator but rather a right to try to exclude by asserting the patent in court. When a patent holder asserts its patent against an alleged infringer, the patent is rolling the dice. If the patent is found invalid, the property right will have evaporated". Thus patent strength refers to the probability to recover damages, with the consequence that only strong patents give in principle to the patent holder the right to exclude an infringer or to force him to buy a license. But as we argue below, even holders of weak patents may escape the uncertain litigation process. They succeed through their licensing strategies to capture a significant part of the consumer’s surplus. This is why the notion of patent quality enters so forcefully in the agenda of antitrust authorities nowadays, especially through criticism of the examination system of the Patent Office (Merges, 1999, Lemley, 2001).