In response to the last post, several people (including a commenter below) have mentioned to me that take-home finals are not new to Harvard. And they are common at other universities, and indeed in other Harvard schools. So what is different about the College that such a disaster could occur?
First, to fill out the history. Yes, professors have been giving take home exams during Reading Period for years, probably with increasing frequency. Since what happens during Reading Period is not centrally monitored, professors who did not want to deal with the rigid protocols for administration of final exams during exam period were rolling their own exam protocols, in-class or take-home, during Reading Period. The College's decision to flip the default doubtless had something to do with frustration with having to grant so many permissions for exam substitutions. But it was dangerous to respond by letting faculty do whatever they wanted.
Some forms of take-home exam work better than others. The exam protocol for the infamous Congress class was that students had eight days to do the exam; it was posted at the beginning of Reading Period and had to be turned in by 5pm on the last day of Reading Period. So there were students who put off doing the exam, because they were writing term papers, having dinner every night with roommates who did the take-home exam right away so they could study for other exams closer to the time they were taking them. That was a recipe for disaster, under the rules that students were not to be discussing the exam with each other.
An exam that had to be done over a 24-hour period would suffer less from that failure mode. But if that 24-hour period were a particular calendar day during Reading Period, then the lack of synchronization between courses would create the possibility that some unlucky soul would have four of those exams to do in the same 24-hour period. That, of course, is the problem that Exam Period was designed to avoid! By having classes that meet at different hours centrally allocated to different exam slots, no student would have to take different exams at the same time.
Technology has created another solution. Today a professor can post the final exam in such a way that a clock starts the instant an individual student downloads it. Each student must upload his or her response within 24 hours, but the students do not all have to be synchronized with each other. Of course this does not eliminate the possibility of information flowing from student to student, but the structure of the protocol reinforces the message that collaboration is not allowed, in exactly the way the structure of the Congress exam signaled the opposite, whatever the instructions said. (HBS gives exams this way.)
All this raises a larger question, which I hinted at near the end of the previous post. Harvard has been giving exams for hundreds of years. Have we really forgotten how to think through that there are better and worse ways to do it? The protocol in this course was amateurish.
Part of what has happened is that the university administration is increasingly deregulatory---if faculty members want to do their own thing, it seems, we might as well allow them to do it. I know how hard it is to herd these cats, but the collapse of regulations, norms, and even memory is dangerous. For all that we have to say these days about pedagogical improvement, the role of the Bok Center for Teaching and Learning, the Conversations@Harvard series on the future of the university, and so on, there is remarkably little practical guidance to faculty on how to avoid these avoidable disasters.