December 2025

IZA DP No. 18344: How Home Exams and Peers Affect College Grades in Unprecedented Times

Tinna Laufey Ásgeirsdottir, Marco Francesconi, Ásthildur M. Johannsdottir, Gylfi Zoega

Leveraging administrative data from the University of Iceland, which cover more than 60% of the undergraduate population in the country, we examine how home exams and peer networks shape grades around the COVID-19 crisis. Using difference-in-difference models with a rich set of fixed effects, we find that home exams taken during university closures raised grades by about 0.5 points (about 7%) relative to invigilated in-person exams outside the pandemic period. Access to a larger share of high-school peers leads to an average grade increase of up to two-fifths of a point, and exposure to higher-quality peers yielded additional, but smaller gains. Interactions between peer-network measures and the COVID/home-exam indicators are near zero, providing no evidence that peer networks amplified home-exam gains during the pandemic.