  To limit the spread of the novel coronavirus on college campuses, a common
strategy for the Fall 2020 and Spring 2021 terms has been to offer instruction
weighted toward hybrid or fully online modalities. Colleges are now considering
whether and how to expand hybrid or fully in-person instruction for future
terms, and learn lessons from this experience for future use. Our paper uses
Fall 2019 enrollment data for a medium-sized public American university to
analyze whether some student groupings by class standing or course level are
more susceptible to the spread of infectious disease through academic
enrollment networks. Replicating Weeden and Cornwell [8], we find that
enrollment networks at the institution are "small worlds" characterized by high
clustering, short average path lengths, and multiple independent connections.
Connectivity decreases as class standing (graduate vs. undergraduate; senior
vs. freshman) and course level increase; as students move from generalized to
specialized course loads, networks cluster by major. Holding other factors
constant, policies focusing on in-person instruction for lower division
students conflict with the greater risk of infectious spread through a lower
division network in the absence of additional steps to minimize academic
connectivity. There are academic and financial incentives for emphasizing the
freshman experience, including concerns about student attrition from the first
to second academic year and recouping costs of infrastructure investments in
dormitories. Possible solutions could include (i) restricting face-to-face or
hybrid instruction to courses in students' academic majors, which would disrupt
larger networks into smaller ones and thus restrict the spread of infection
across majors, and (ii) take a "scalpel" approach to instruction modes by
moving online courses most likely to facilitate epidemic spread.
