When skilled labour is imported, skill levels of local workers may be raised by
contact with new techniques and practices. European basketball offers an
opportunity to test this general claim. For a panel of 47 countries observed over
more than twenty years, we model probability of qualification for, and performance
in, international tournaments. We demonstrate that an increase in the number of
foreigners in a domestic league tends to generate an improvement in the
performance of the national team (which comprises only local players). Given this,
we develop a theoretical framework for how a regulator might take this into account.