One of the tips for lecturers is to connect with the audience by asking questions. As a student, I found myself in situations where I gave a suitable answer, and the instructor would say “wrong” and wait for other answers. Back then I thought: “What an asshole, I answered correctly.” This often happens when a question doesn’t have a clear answer, for example: “What’s the single biggest difference between Android and iOS?”
When I became an instructor myself, I also started asking the audience questions, to get them moving, to make the students’ brains work. And after a wrong answer, I started catching looks that said: “What an asshole, I answered correctly.” That situation was uncomfortable.
Years later I arrived at the concept of the “control answer.” A control answer is the answer the teacher expects to hear. For example, according to the lecture plan, after the question “What’s the difference between programming mobile apps and desktop apps,” you need to talk about energy saving, so the control answer is: “On mobile, you need to conserve battery charge, which means using hardware resources efficiently.” So when students talk about user-interface paradigms or the use of cloud services, I say: “Good idea, but the control answer is different,” and we continue the discussion.