Much of the policy debate over the patent system has focused on theperceived problems with non-practicing entities (NPEs), also called patenttrolls. Drawing on a comprehensive data set we built of every patentlawsuit filed in 2008 and 2009 that resulted in a ruling on the merits, wefind that the situation is rather more complicated than simply operatingcompanies vs. NPEs. While operating companies fare better in litigationthan NPEs overall, breaking NPEs into different categories reveals morecomplexity. Patent Assertion Entities (PAEs) in particular win very fewcases. Further, once we remove certain pharmaceutical cases from the mix,no patent plaintiff fares very well. That is particularly true of software,computer, and electronics patents.