The incidence and role of negative citations in science.

Citations to previous literature are extensively used to measure the quality and diffusion of knowledge. However, we know little about the different ways in which a study can be cited; in particular, are papers cited to point out their merits or their flaws? We elaborated a methodology to characterize "negative" citations using bibliometric data and natural language processing. We found that negative citations concerned higher-quality papers, were focused on a study's findings rather than theories or methods, and originated from scholars who were closer to the authors of the focal paper in terms of discipline and social distance, but not geographically.