A new study helps to fill the gap by providing systematic data on the growth of patent troll litigation. Robin Feldman, a professor at UC Hastings College of Law, teamed up with Lex Machina, a Stanford Law spinoff that collects data on patent litigation, to compile a systematic survey of patent litigation. Their results are striking: the fraction of lawsuits filed by troll-like entities grew from 22 percent in 2007 to 40 percent in 2011.

via Trolls filed 40% of patent infringement lawsuits in 2011 | Ars Technica.