Researchers studying innovation increasingly use indicators based on patent citations. However, it is well known that not all citations originate from applicants - patent examiners contribute to citations listed in issued patents - and that this could complicate interpretation of findings in...

This paper takes a close look at the reasons, procedures, and results of cluster identification methods. Despite being a popular research topic in strategy, economics, and sociology, geographic clusters are often studied with little consideration given to the underlying economic activities, the...