Stefan Wagner is currently visiting us from Munich. Last week he presented a research paper on patent thickets (coauthored with Georg von Graevenitz and Dietmar Harhoff). The main contributions of the paper are (a) explaining how “complexity” is not just about how difficult a technology is to master, but also about whether firms have to commercialize discrete versus interconnected facets of technological knowledge, and (b) they present an empirical analysis of European patent data, using a novel measure of whether prior patents are deemed to be “blocking” each focal innovation. If you would like to watch the highlights of his seminar, I have posted a video at http://vimeo.com/3445520. You can download the paper from SSRN or contact Stefan for a copy.