Targeted COVID-19 Testing at the Greek Border

Faculty: Hamsa Bastani

Opportunity: allocate a limited daily budget of COVID-19 tests to screen a subset of international travelers to Greece.


  • Targeted testing of “high-risk” travelers can maximize the # of active infections identified.

Challenge: feedback loop (today’s testing decisions determine tomorrow’s data).


We use a nonstationary batched contextual bandit algorithm, which we deployed nation-wide to test millions of travelers in Summer 2020.