The cost of bad patents

There seems to be more and more recognition of the idea that more and more patents aren't necessarily a good thing. This blog post points to a paper (PDF) that tries to quantify the costs of bad patents.

The authors then go on to do a rough estimate of the associated social cost by using comparative data on patents from the US, Japan and the EPO, where the other two patent offices are held to have higher standards. Using this, they estimate that bad patents create a $25.5 billion annual loss to society.