See Missunitwocents on sunk costs and the university lecture.
“But we desperately want live lectures to work. We’ve done them for so long now that they seem a part of who we are. And we are tantalised by the mirage of thinking that if only everyone turned up, they would be a far more efficient way of teaching than the seminar or the tutorial.”
I agree; things need to change. Something about lectures, as they have been, is not appropriate to the way things are going for many of our students. At the mass-management level, and thinking about spaces and resources, they are not “working” as an efficient use of time and space, investment, etc. But, looking at the graph of attendance, is the lecture “not working” for the 50% of students who are attending? The question is thrown back on to understanding why some students attend, and others don’t. What goes on in the lecture? What goes on in the student’s life? And if we ask these questions about lectures, we also need to ask them about our other class formats.
This is, of course, the complex question of student “engagement”. Something fundamental has changed about the way that students think of their activities and time. But I’m not sure we know what to do in response.