Requiring Versus Recommending Preparation Before Class: Does It Matter?

Asking students to come to class prepared is quite common in undergraduate and graduate education. We use a quasiexperimental design to assess whether requiring undergraduate students in an introductory course to review prior to lecture the material that will be taught in class enhances their understanding of key concepts. We find that requiring rather than recommending preparation before class increases exam scores by about a quarter of a standard deviation, or roughly a third of a letter grade, for students in the second and third quartiles of the ability distribution but has little impact on very high‐ or low‐ability students. We also estimate local average treatment effects, from which we draw a similar conclusion: reviewing the material before lecture benefits students in the middle of the ability distribution but has essentially no impact on the top and bottom quartiles.