Defying the pessimists who doubted the ability of Yale students to follow COVID-19 safety protocols, the Yale student body conducted itself in a safer manner than expected last semester. To put a number on it, the R0 value, or the number of secondary cases generated by an initial case, of the student body last semester was 1.85—compared to the 2.3 that experts set as the maximum value that could still keep student infections under control. Yale researchers Joseph Chang, Forrest Crawford, and Edward Kaplan calculated this number and devised the twice-weekly testing plan implemented among Yale College’s on-campus student body last semester.
Yale Scientific/April 25, 2021