Innovation in SMEs exhibits some peculiar features that most traditional indicators of innovation activity do not capture. Therefore, in this paper, we develop a structural model of innovation which incorporates information on innovation success from firm surveys along with the usual R&D...

The analysis of patent and citation data has become a popular source of evidence on localized knowledge spillovers and innovation. Nevertheless, one aspect has been overlooked: the patent distribution across inventors is extremely skewed, as many inventors -- the comets -- register one or few...