The many faces of mobility: Using bibliometric data to track scientific exchanges.

This paper presents a methodological framework for developing scientific mobility indicators based on bibliometric data. We identify nearly 16 million individual authors from all publications covered in the Web of Science for the 2008-2015 period. Based on the information provided across individuals' publication record, we propose a general classification by which to analyze scientific mobility via institutional affiliation changes. We distinguish between migrants - those who have ruptures with their country of origin - and travelers - those who gain additional affiliations while maintaining affiliation with the country of origin. We find that 3.7 percent of researchers who have published at least one paper over the period are mobile. We also find that travelers represent 72.7 percent of all mobile scholars, but that migrants seem to consistently have higher scientific impact. We then apply this classification at the country level, and expand these the traveler/migrant classification based on the directionality of scientists' mobility (incoming and outgoing). Our results illustrate the various forms taken by scientific mobility, and highlight the utility of our classification for understanding it.