As a math teacher, I've seen varying levels of success using the reverse/flipped classroom style of teaching/learning. Unfortunately, some teachers blindly assume that all the students will be (a) motivated to do all the required reading and studying overnight, and (b) able to grasp at least a basic understanding of the information, before class the next day. Sometimes, those don't work out as planned. While the assigned material is hopefully a decent enough primer for the following day, the following day (when the students come back to class) needs to be really well-structured by the teacher, to reinforce/boost the students' understanding of last night's packets. Usually, this comes in the form of a collaborative discussion, problem set, or something else a little more substantial than a simple Q&A where the professor answers some questions (as some students might not even know, or be able to formulate, the kinds of clarifications they need). It depends on the teacher, the students, and sometimes even the topic being learned. Some students prefer this method, while others prefer a more direct approach from a lecturer, while still others prefer exploring a new concept with a partner or small group. There's a lot of interesting - and often conflicting or ambiguous - research out there about which teaching methods are "best", but a lot of it is really subjective.