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Oct 15, 2013 (4 years and 6 months ago)


Debating the ‘Flipped Classroom’ at Stanford

January 5, 2012, 12:35 pm

Marc Parry

Stanford University got lots of

for inviting the public to
participate in a series of free online computer
science classes. One thing that’s drawn less notice
s how some of the technologies that help facilitate those mega
classes are changing the
experience for Stanford students learning the same subjects. Now a Stanford student is provoking
a debate on those innovations, with a
blog post

critiquing the rigor and format of the “flipped
classroom” teaching method deployed in his machine
learning course.

In one version of that course offered to Stanford students
, the traditional teaching format was
inverted, with lectures presented through online videos and optional once
week class meetings
devoted to problem solving with the professor. The videos, plus auto
graded assignments, were
also offered to the public i
n the free online version of the machine
learning class. As of
November, a staggering 94,000 people had signed up to take that course.

But Ben Rudolph (pictured above), a junior majoring in computer science, provoked a


on Hacker News with a blog post attacking the largely online version of that
class that was offered to Stanford students. He faulted the course, “CS229A: Applied Machine
Learning,” for insufficiently challenging ass
ignments and for swapping live lectures with canned

“Online lectures suck. Sure, they’re great for rainy days or people learning at a distance or
people that don’t go to Stanford. However, these new classes are getting rid of in
person lectures
pletely. I met barely anyone in my CS229a class. Everything was done alone in my room,
which is kind of crappy especially when there is such a nice campus right outside.”

“The initiative that Stanford has taken to open up education is great. However, God h
elp me if all
my classes become 2 hour weekly online lectures with review questions and auto
programming exercises. Stanford can expect a letter from me asking to get a cut in my tuition if
the classes begin to go the way of CS229a.”

Mr. Rudolph too
k particular exception to the programming exercises, in which the computer
automatically informed students whether or not they got 100 percent on the task. “It’s so black
and white,” he tells Wired Campus. “They have to make it easy enough so everyone can
get 100
percent, basically. In the past I’ve turned in programming assignments, and only the really smart
kids got stellar scores, because they went above and beyond. This model kind of discourages

In one sense, Mr. Rudolph doesn’t have much to comp
lain about. Stanford also offered a
traditional version of machine learning via another class

CS229, taught by the same professor,
Andrew Y. Ng

with live lectures twice a week. What’s more interesting is his worry about the
spread of technologies that faci
litate teaching to a mass audience, as well as his take on the
“flipped classroom,” a teaching format getting lots of buzz lately largely through the work of the
tech star
alman Khan

According to Mr. Ng, that format first appealed to Stanford professors as a way to improve
education for the university’s own students, not to accommodate the general public, as Mr.
Rudolph suggests. Prior to flipping his class, Mr. Ng had alre
ady been offering students the
option of watching video recordings of his lectures at home rather than attending the lectures in
person. The average in
class attendance hovered around 30 percent of students.

“The vast majority of students in my class were
not showing up to class, and they were choosing
to watch videos of me instead of showing up to the live classroom,” Mr. Ng says. “If students
prefer to watch videos online anyway, then maybe we can do much better.”

In particular, Mr. Ng thinks the online e
xperience can be improved through shorter, more
topically coherent videos, and interactive quizzes.

Right now, when Mr. Ng asks a question in class, here’s what happens: Half the room is still
madly scribbling away, he says. Maybe one
quarter of the studen
ts are on Facebook. And there’s
sometimes one “smarty
pants” in the first row who blurts out a response.

”Essentially, only one
student in a class gets to attempt an answer,” he says. “Whereas in contrast, using online videos
and interactive quizzes, every

student gets to attempt an answer.”

As for auto
graded assignments, Mr. Ng stresses the benefits of instant feedback over the
traditional method of returning assignments weeks after students learned the material.

And notwithstanding Mr. Rudolph’s complain
ts, early responses are encouraging: Teaching
evaluations for the “flipped” version of the class (CS229A) were comparable to those for the
traditional class (CS229). So, too, were students performances on the final project, which was
graded based on the sa
me criteria for both the traditional class and the new “applied” version of

“This was surprising, because even though CS229A had fewer prerequisites and thus many
students in CS229A had come in to the class with a weaker mathematical background, this s
that they nonetheless learned enough to perform essentially identically to CS229 students in
terms of getting machine
learning algorithms to work,” Mr. Ng says. The professor sees this as
evidence that “the flipped classroom medium in CS229A is even m
ore effective than the
traditional lecture
based CS229 one for teaching students machine learning.”

Another student, Kevin Khoa Nguyen, agrees with Mr. Rudolph that the new class had been one
of the easiest computer
science courses in his time at Stanford.

Mr. Nguyen tells Wired Campus
that he is a big fan of the online lecture format, however.

“I think this is the future of education,” he says. “The videos save a lot of time in going to class
and the use of efficiently displayed diagrams takes away the ove
rhead in drawing diagrams on a
whiteboard. Obviously, this approach comes at a cost of classroom interactivity, which can be
remedied with sites like
,” an online forum where students can ask questions.

What do you

think? Is this the future of education? Or a misguided innovation?