Most important for our purpose, teachers were asked what proportion of time in a typical week students spent on each of eight in-class activities. The overall time in class apportioned to three of these activities—listening to lecture-style presentation, working on problems with the teacher’s guidance, and working on problems without guidance—likely provides a good proxy for the time in class in which students are taught new material. We divided the amount of time spent listening to lecture-style presentations by the total amount of time spent on each of these three activities to generate a single measure of how much time the teacher devoted to lecturing relative to how much time was devoted to problem-solving activities.