An Analysis of the Connection between Researchers ' Productivity and their Co- authors ' Past Attributions, including the Importance in Collaboration Networks1

Many studies have analyzed the "synchronic " correlation of properties, i.e., the correlation of properties in the same period, between authors and their co-authors. However, the "diachronic " correlation of properties, i.e., the correlation between their subsequent and precedent activity, has not yet been sufficiently studied using quantitative methods. This study pays attention to not only productivity but also the importance in the collaboration network as a measure of the researcher's activity, and clarifies whether there is any connection between (i) the researcher's activity subsequent to a collaboration and (ii) the collaborator's precedent activity, aiming at deriving knowledge about the diachronic effect of collaborators. The targets analyzed in this study are the newcomers who had first appeared in the domain of computer science in 1998 and their co-authors. The results show very little correlation between the subsequent activity of newcomers and the preceding activity of their co-authors. However, there are significant differences in the co-author's precedent activity between the newcomers who have published no papers after their first publication (those who have not become visible researchers) and the newcomers who have published at least one paper after then (those who continue to produce papers)