On a warm spring evening, after the kids have gone to bed, Stanford computer science professor Chris Manning sits down in his home office. Turning on his Mac laptop and an attached Wacom pen tablet, he looks into his webcam and hits the record button. Welcome to CS276, Information Retrieval and Web Search.

When the class meets later that week at Stanford's NVIDIA Auditorium, the affable Australian professor assumes that his students have watched the recorded lecture already. So instead of rehashing that material, he asks them to pair up for a group programming challenge. The students murmur. Laptop keyboards click. Manning, PhD '95, and his TAs roam the aisles offering help. Fifteen minutes later someone has come up with a solution, 30 lines of code, and the class reconvenes to go over it.

Rukmani Ravi Sundaram, a master's student, says she likes the new flipped/online model. "Getting the lectures in advance helps because I'm able to watch them at my own pace and I like working in teams in class. If you're stuck with something you can get help." She's not alone. When computer scientists Daphne Koller and Jennifer Widom taught their first flipped/online classes, both found that their teaching ratings went up. "I wish every course were this straightforward!" one anonymous Stanford student raved. "The videos clearly seemed like the future of education."

Michele Marincovich,'68, the longtime director of Stanford's Center for Teaching Learning, says one advantage of the flipped/online model is the way it engages people. In the traditional lecture setting, she notes, "many students are more or less transcribing without really thinking, whereas if they are actively engaged—if they help to construct their own knowledge—they seem to learn it better."

Some Stanford students aren't so sure. Though computer science graduate student Rio Akasaka enjoyed Widom's flipped/online databases course last fall, he was less enthusiastic about Thrun's course on artificial intelligence. "There was quite a bit of outspoken criticism," he recalls, "about the lack of updates and the perception that the staff were overwhelmed with taking care of the free offering instead of addressing concerns that we as Stanford students had."

An on-campus blogger who took the applied machine learning class last fall voiced concerns about the relative simplicity of the programming assignments as the quarter wore on, compared to those given in regular computer science classes. Other students complain that the courses have too much busywork—even when the flipped portions are optional, as they often are. "I really enjoy having the offline videos and I think I would be worse off if the lecture material was shifted back into in-class time," one spring quarter student wrote, "but with all the at-home video lectures, online quizzes and in-class programming exercises, it's honestly a headache to keep track of which assignments are due when, and what lectures and handouts to watch and read."

Manning, for his part, has enjoyed the two flipped/online courses he's been involved with so far, even though they are a lot of work to produce. "I'm feeling excited, like this is really working," he says after the group coding session. "You spend a lot of time playing around with PowerPoint, a lot of time getting everything just right in your head so you can do it in real time, drawing on the slide without messing up. This is clearly being propelled through a lot of extra faculty sweat." Nevertheless, he says, "It's been fun doing it."