  Many centralized matching markets are preceded by interviews between
participants. We study the impact on the final match of an increase in the
number of interviews for one side of the market. Our motivation is the match
between residents and hospitals where, due to the COVID-19 pandemic, interviews
for the 2020-21 season of the National Residency Matching Program were switched
to a virtual format. This drastically reduced the cost to applicants of
accepting interview invitations. However, the reduction in cost was not
symmetric since applicants, not programs, previously bore most of the costs of
in-person interviews. We show that if doctors can accept more interviews, but
the hospitals do not increase the number of interviews they offer, then no
previously matched doctor is better off and many are potentially harmed. This
adverse consequence is the result of what we call interview hoarding. We prove
this analytically and characterize optimal mitigation strategies for special
cases. We use simulations to extend these insights to more general settings.
