Pre-Recorded Lectures, Live Online Lectures, and Student Academic Achievement

In the midst of the COVID-19 pandemic, universities throughout the world are embracing online learning, often depending on synchronous and asynchronous digital communications. In this paper, we compare the impacts of live online (synchronous) and pre-recorded (asynchronous) lectures on student achievement using a randomized experiment. We discovered that pre-recorded lectures reduce lower-ability students’ academic achievement but have no effect on higher-ability students’ academic achievement. In particular, being taught via pre-recorded lectures as opposed to live online lectures decreased the likelihood of answering exam questions correctly by 1.6 percentage points for students in the bottom 50th percentile of the ability distribution (measured by GPA at the beginning of the semester). Furthermore, being taught via pre-recorded lectures in the starting weeks of the semester compared to the later weeks tended to be more harmful to students’ academic achievement. These findings have important implications for the effective design of education policies.