  Geographic proximity is acknowledged to be a key factor in research
collaborations. Specifically, it can work as a possible substitute for
institutional proximity. The present study investigates the relevance of the
"proximity" effect for different types of national research collaborations. We
apply a bibliometric approach based on the Italian 2010-2017 scientific
production indexed in the Web of Science. On such dataset, we apply statistical
tools for analyzing if and to what extent geographical distance between
co-authors in the byline of a publication varies across collaboration types,
scientific disciplines, and along time. Results can inform policies aimed at
effectively stimulating cross-sector collaborations, and also bear direct
practical implications for research performance assessments.
