I wish I could think about it more now, but with a test tomorrow, grandmothers are dying like flies. We know they learn best if they are required to master material one stage at a time before proceeding to new material. We know they learn best if their errors are immediately corrected. We know they learn best if they are graded, not by a single final exam, but by how much material they master. Traditional university lecturing cannot provide this kind of instruction.
Small tutorials can, but they are very expensive.
While the initial costs for development are high, in contrast to the tutorial system, the continuing costs of instruction by computer are low. With instruction delivered over the Internet, scheduling difficulties almost disappear and students can flexibly and rationally allocate their time. My STAT100 class has 200 students, and I lecture twice a week for 80 minutes each. I cannot seem to get much interaction going. I do have in-class assignments, which help.