How does co-authoring with a star affect scientists' productivity? Evidence from small open economies

There is increasing policy interest in the recruitment and integration of star scientists as a mechanism to catalyse research productivity. We use rich data for three Small Open Economies (Ireland, Denmark, and New Zealand) on publications, citations and co-authorships to examine how co-authorship with a co-located star scientist affects the co-author's productivity, both including and excluding the output directly co-authored with the star. The latter effect provides a measure of the extent to which star collaborations crowd out/in other output. Event-study analyses reveal that star co-authorships are associated with economically and statistically significant increases in co-authors' output (measured by field-normalized total citations). Output in the three years after the initial star co-authorship is increased by 89.6 % when star co-authored publications are included and by 16.2 % when they are excluded. The results are robust to using an alternative measure of quality-adjusted output based on journal publication quality. We find co-authoring with a star increases the quality but not quantity of output when star co-authored publications are excluded. We explore heterogeneity by period, field and whether the authors have multiple star co-authorships. We conclude that policymakers' and institutions' efforts to promote access to star scientists may have substantial direct and indirect effects on the productivity of incumbent scientists within departments.