Epidemiological Modeling

The health of our campus community and the greater Ithaca area were key considerations in Cornell’s plan to invite students to campus for instruction. To guide this decision-making, the university relied on numerous evidence-based sources, including the findings of epidemiological modeling by experts on our faculty.

Analysis of Fall 2021 Classroom COVID-19 Transmission

In this analysis, Operations Research and Information Engineering Professor Peter Frazier and partners (the Cornell COVID-19 modeling team) use a theoretical model and data published in the scientific literature to estimate the probability faced by an individual of becoming infected with COVID-19 due to classroom interaction over the course of the fall 2021 semester. Their analyses of the risks to undergraduate students, faculty instructors, and graduate student teaching assistants incorporated the effect of masking in class, physical distancing, and ventilation. The nominal estimate of this probability for vaccinated faculty instructors is 0.017%, or about 1 in 6000.

Report: Analysis of Fall 2021 Classroom COVID-19 Transmission (PDF) (October, 2021)

Modeling for Cornell’s Fall 2021 Semester

Operations Research and Information Engineering Professor Peter Frazier and partners (the Cornell COVID-19 modeling team) performed modeling at the start of the fall semester to incorporate new information to study the impact of new interventions brought to bear against cases in the student population at that time. Interventions included more frequent surveillance testing for students affiliated with Greek Life organizations; stronger measures that improved compliance with student surveillance testing; increased staffing allocated toward contacting positive individuals and performing contact tracing; and a more robust adaptive testing program. Case trajectories since these interventions were put into place tracked between the nominal and optimistic scenarios developed at the time. While significant uncertainty remains about cases going forward and work continues to understand and combat the spread of virus, modeling suggests that these interventions played a significant role in reducing infections among students.

Report: Modeling for Cornell’s Fall 2021 Semester (PDF) (updated September 19, 2021)

Mathematical Modeling for Cornell’s Spring 2021 Semester

Over the winter break, Cornell's pandemic modeling team updated a mathematical model of the spread of COVID-19 originally developed for the 2020 fall semester. The model was updated to incorporate information on student and employee COVID-19 cases at Cornell during the fall semester; rising prevalence in the Southern Tier and the country as a whole; and the evolution of faster-spreading variants of SARS-CoV-2 from the United Kingdom, Brazil and South Africa. Based on this updated model, the team then identified likely scenarios for what might unfold over the spring semester and studied proposed modifications to Cornell's COVID-19 measures. This supported Cornell's preparation for the spring, and showed that modifications to the surveillance testing program, new contact tracing and supplemental testing programs for employees, travel restrictions and other modifications positioned Cornell to address the possible challenges of the spring semester.

Report: Mathematical Modeling for Cornell’s Spring Semester (PDF) (published February 16, 2021)

Mathematical Modeling for Cornell's Fall 2020 Semester

In an initial analysis (June 2020), Operations Research and Information Engineering Professor Peter Frazier and partners (the Cornell COVID-19 modeling team) found that residential instruction, when coupled with a robust virus screening program, allows Cornell to provide more thorough safeguards for public health than a fully online semester. Student surveys revealed that a large number of Cornell students would choose to return to Ithaca, even if classes were fully online, and they would live together and socially interact. Offering in-person instruction allows Cornell to impose mandatory virus screening tests and behavioral requirements for students to follow as part of a residential semester.

Report: COVID-19 Mathematical Modeling for Cornell's Fall Semester (PDF) (published June 15, 2020)

Addendum: COVID-19 Mathematical Modeling for Cornell's Fall 2020 Semester

The Cornell COVID-19 modeling team updated its analysis in July 2020 after examining feedback on its initial report and in light of the changing progression of the virus nationally. This updated analysis studies numerous alternative parameters, including ways of calculating the number of contacts per day among members of the campus community, the effects of greater numbers of contacts per day, the effects of community members failing to comply with testing and the effect of offering testing to students who are taking classes online only.

Report: Addendum: COVID-19 Mathematical Modeling for Cornell's Fall Semester (PDF) (published July 17, 2020)

Gateway Testing and Quarantine Capacity

Another updated analysis carried out by the Cornell COVID-19 modeling team in August 2020 studied the effectiveness of gateway testing (or “arrival testing”) for addressing the rising prevalence of COVID-19 in parts of the U.S., a potential lack of test access for some Cornell students in their home location, and the requirement that individuals traveling to New York state from states where the COVID-19 prevalence is high must self-quarantine upon arrival.

Report: Gateway Testing and Quarantine Capacity (PDF) (published August 11, 2020)

Update for Assemblywoman Lifton

The following document was prepared by the Cornell COVID-19 modeling team to update New York State Assemblywoman Barbara Lifton on two points of importance: the rise in national COVID-19 cases during the month of July and the projected impact of the Cornell reopening decision on the greater Ithaca community. This follows a broader discussion between President Martha Pollack and Assemblywoman Lifton and reflects questions asked by others.

Report: Update for Assemblywoman Lifton (PDF) (published August 9, 2020)