Little experimental evidence exists on the causal impact of class time on academic
performance when students have access to extensive course material online. We
randomized 725 college students into traditional twice-per-week and compressed once-per-
week lecture formats in introductory microeconomics. Students in the traditional format
scored 3.2 out of 100 points higher (0.21 standard deviations) on the midterm than those in
the compressed format but a statistically insignificant 1.6 points higher (0.11 standard …