Multiscale impact of researcher mobility.

Alexander M Petersen

doi:10.1098/rsif.2018.0580

Abstract

International mobility facilitates the exchange of scientific, institutional and cultural knowledge. Yet whether globalization and advances in virtual communication technologies have altered the impact of researcher mobility is a relevant and open question that we address by analysing a broad international set of 26 170 physicists from 1980 to 2009, focusing on the 10-year period centred around each mobility event to assess the impact of mobility on research outcomes. We account for secular globalization trends by splitting the analysis into three periods, measuring for each period the effect of mobility on researchers' citation impact, research topic diversity, collaboration networks and geographical coordination. In order to identify causal effects we leverage statistical matching methods that pair mobile researchers with non-mobile researchers that are similar in research profile attributes prior the mobility event. We find that mobile researchers gain up to a 17% increase in citations relative to their non-mobile counterparts, which can be explained by the simultaneous increase in their diversity of co-authors, topics and geographical coordination in the period immediately following migration. Nevertheless, we also observe that researcher's completely curtail prior collaborations with their source country in 11% of the cross-border mobility events. As such, these individual-level perturbations fuel multiscale churning in scientific networks, e.g. rewiring the connectivity of individuals and ideas and affecting international integration. Together these results provide additional clarity on the complex relationship between human capital mobility and the dynamics of social capital investment, with implications for immigration and national innovation system policy.

Highlights

The dispersion of knowledge across institutional and national borders is fundamental to scientific progress
While the professional prospects and call of adventure associated with relocation may be alluring to some, there are risky trade-offs associated with physical relocation that require careful assessment of local versus non-local socio-economic, family, work and funding opportunities [1,2,3,4]
To what degree does researcher mobility affect scientific impact, topical direction and collaboration? we describe the Rubin causal inference framework [51] as it applies to estimating the impact of cross-border mobility on various quantitative researcher career metrics

Summary

Introduction

The dispersion of knowledge across institutional and national borders is fundamental to scientific progress. While the professional prospects and call of adventure associated with relocation may be alluring to some, there are risky trade-offs associated with physical relocation that require careful assessment of local versus non-local socio-economic, family, work and funding opportunities [1,2,3,4]. This common dilemma factors into the cost of human and social capital investment in science, which is rather substantial and continues to grow with the globalization of the scientific endeavour [1,5]. Our results contribute to the literature on how knowledge flows [7,8] and how careers grow [9] following pivotal events—e.g. winning the Nobel Prize [10], initiating a dedicated

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