Research impact and scholars' geographical diversity

In recent years there has been a sharp increase in collaborations among scholars and there are studies on the effects of scientific collaboration on scholars' performance. This study examines the hypothesis that geographically diverse scientific collaboration is associated with research impact. Here, the approach is differentiated from other studies by: (a) focusing on publications rather than researchers or institutes; (b) considering the geographical diversity of authors of each publication; (c) considering the average number of citations a publication receives per year (time-based normalization of citations) as a surrogate for its impact; and (d) not focusing on a specific country (developed or developing) or region. Analysis of the collected bibliometric data shows that a publication impact is significantly and positively associated with all related geographical collaboration indicators. But publication impact has a stronger association with the numbers of external collaborations at department and institution levels (inter-departmental and inter-institutional collaborations) compared to internal collaborations. Conversely, national collaboration correlates better with impact than international collaboration. (C) 2013 Elsevier Ltd. All rights reserved.