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World’s Most Popular Online Course Adopts AI: Harvard’s CS50

The most popular online education class in the world—with 40,000 students enrolled virtually each semester—is Harvard University’s CS50. And starting in the fall of 2023, Harvard will integrate generative artificial intelligence into the course’s instruction.

This introductory computer science course is Harvard’s largest on-campus class, with 1,600 students attending each year in Cambridge, Massachusetts. Moreover, almost five million students have enrolled since the university’s undergraduate division Harvard College first offered this class in 1989. After the university opened up CS50 to online students in 2007, four million online students have enrolled. And recently, enrollment has roughly doubled just in the two years since 2021.

Most of those students enrolled through edX, the massive open online course (MOOC) platform launched by Harvard and MIT which sold in 2021 for $800 million. The 2023 online course closely emulates the on-campus Harvard experience, in the sense that both course versions have identical lectures, readings, assignments, and final software projects. Oddly enough, this phenomenal course also maintains its own YouTube site with 1.4 million subscribers—and even sells branded merchandise like t-shirts.

Meet Superstar Professor David Malan

What’s driving all this explosive growth is the entertaining showmanship of the course’s rock-star professor who has taught CS50 since 2007, Dr. David Malan. Traditionally at research universities, lectures teaching dry computer science fundamentals like loops, arrays, and data structures in programming languages like C put many of the students to sleep, but that’s clearly not the case at Harvard. As this YouTube video demonstrates, Professor Malan lectures in an electrifying, hyper-engaging style that captivates both his online and in-person audiences.

Harvard now plans to apply generative artificial intelligence to reduce the workload on the 50 teaching assistants assigned to the course. In an interview with Bloomberg, Dr. Malan reported that his TAs faced challenges responding to increasing numbers of students with diverse levels of experience and knowledge logged in from different time zones worldwide. “Providing support tailored to students’ specific questions has been a challenge at scale, with so many more students online than teachers,” he explained.

Even before the advent of global online education, large lecture courses at major research universities across America have for decades been chronically plagued by complaints from overworked and poorly-paid graduate teaching assistants, and Harvard is no exception. The workload became so severe at the University of California that a strike by teaching and research assistants broke out late in 2022. That labor action just before final exams shut down classes and interrupted work by graders and academic advisors.

Dr. Malan suggested that CS50’s new artificial intelligence system would offer personalized learning suggestions and provide feedback on student assignments through a virtual teaching assistant. Although he didn’t offer details, Harvard’s virtual TA will likely function much like a famous artificial intelligence chatbot system at the Georgia Institute of Technology which we first covered here at in 2020.

Currently supporting students within 17 online computer science classes, Georgia Tech’s “Jill Watson” virtual TA is an AI adaptation of IBM’s Watson rapid question-answering technology that in 2011 won $1 million on the TV game show Jeopardy! These days Jill answers student questions within discussion forums and personal chats in such a friendly and lifelike manner that she fools just about everybody. A survey at the end of Jill’s first semester in 2016 showed that students in an online artificial intelligence course could not tell which one of the ten teaching assistants was actually the virtual TA—and a few students had even asked her to lunch.

Dr. Malan says that his course’s new AI teaching assistant will do far more than debug code. He says that the virtual TA will simplify and explain cryptic error messages for students, then recommend “student-friendly suggestions for solving them.” Moreover, because platforms like ChatGPT and GitHub Copilot are “currently too helpful,” he says that the new CS50 bot will ask rhetorical questions to help students learn, such that the technology will be “leading students toward an answer rather than handing it to them.”

He also expects that the virtual TA should give the human TAs “more meaningful, interpersonal time with their students, akin to an apprenticeship model,” such as during office hours. “Our own hope is that, through AI, we can eventually approximate a 1:1 teacher:student ratio for every student in CS50, as by providing them with software-based tools that, 24/7, can support their learning at a pace and in a style that works best for them individually,” Dr. Malan wrote in a statement reported by the Harvard Crimson. And in another interview with Fortune, he continued:

A.I. is certainly at the forefront of our interest right now, particularly as it might allow us more students on campus, and all the more rapidly. The goal with those tools would be for us educationally, to achieve the equivalent of a one-to-one student ratio. Rather than spreading human resources across a large demographic of students—some of whom are doing just fine, some of whom might be struggling—we can concentrate more customized attention on the students who need it most.

Dr. Malan also wrote that the virtual TA will respond to frequently-asked questions from students inside Ed Discussion, an online threaded discussion platform and a popular forum for STEM classes at universities across the nation. A beta-test version of this feature is currently available to students enrolled in CS50 during Harvard’s 2023 summer session.

A Trend Amid Controversy

CS50’s move probably foreshadows a new trend favoring artificial intelligence in higher education because colleges nationwide tend to copy Harvard’s curriculum decisions. However, the action also follows a period marked by controversy over the breakneck pace of recent developments in artificial intelligence technology.

On July 21, the Biden Administration announced that seven of the leading American AI companies had agreed to voluntary technology development safeguards to help manage the risks of the new tools. These firms—which include Amazon, Anthropic, Google, Inflection, Meta, Microsoft, and OpenAI—pledged to honor new security, trust, and safety standards during a White House meeting with President Biden.

Technology leaders like Elon Musk of Tesla and Apple’s co-founder Steve Wozniak had as early as March 2023 called for a temporary hiatus in the deployment of artificial intelligence systems due to these rapid advances.

The seven companies stopped short of agreeing to such a pause even though they pledged their support for the initiative promoted by the White House. “We must be clear-eyed and vigilant about the threats emerging from emerging technologies that can pose—don’t have to but can pose—to our democracy and our values,” said the President in brief remarks from the Roosevelt Room.

Getting Started with CS50

Prospective students who’d like a look at CS50 have a couple of options. First, they could review Dr. Malan’s most recent lectures posted on YouTube. Second, for a more comprehensive look that includes the readings and problem set assignments along with his lectures, they could initially enroll in the course for free through edX, which mostly only charges students who request certificates of completion.

But Fortune’s interview with Dr. Malan also explored some of the controversy related to taking this course for academic credit. Most of the 40,000 online students each semester will take this course from edX to obtain professional development certificate credits, which signal their programming competency to their current and future employers. However, currently, no mechanism yet exists through edX to provide academic credits for the minority of online students who want to apply CS50 towards a college or graduate degree.

In these situations, Dr. Malan says that students must enroll for the course through Harvard’s Summer School or the Harvard Extension School instead of edX. Once their CS50 grade appears on their Harvard transcript, they can then request transfer credit from their degree program. He continues:

Through those channels, students have a more traditional support structure like an assigned teaching assistant, weekly feedback from humans in terms of grades, and ultimately a transcript and official credits that they can apply either to Harvard’s degree programs, or if their own school accepts it, they could transfer that credit to their school.

The Economics of CS50

Not surprisingly, what Dr. Malan didn’t tell Fortune is that massive differences exist in Harvard’s charges for the various CS50 credentials, which are available through four different online platforms. And only one of these platforms offers a certificate of completion for free.

  • edX will allow anyone to audit the entire CS50 course at no charge. The platform offers an ID-verified certificate for $149.
  • As Dr. Malan points out, students enrolled online through either the Extension School or Summer School platforms within Harvard’s Division of Continuing Education can take CS50 for transferable credit and receive official transcripts upon completion. However, the Extension School charges tuition between $1,980 and $3,100, and the Summer School charges $3,500.
  • Harvard OCW is the university’s MOOC platform for open online courses. This is the only platform that offers a CS50 completion certificate at no charge. This offering is identical to edX’s, with only one exception: OCW’s free certificate doesn’t include ID verification.

CS50’s Value to Students and Harvard

Finally, one might suppose that with tuition running as high as $3,500 for each CS50 credit enrollment—or about $1,166 per credit-hour—and this course available to online students all over the world, Harvard would be raking in piles of cash from this class.

Unfortunately, we weren’t able to verify Harvard’s earnings from the class before filing this report. Nevertheless, we did locate an interesting proxy from which we can infer the tremendous value of this course to Harvard and the university’s students: Dr. Malan’s compensation.

Harvard Magazine reports:

For a second consecutive year, McKay professor of the practice of computer science and liaison to the chief technology officer David J. Malan appears on the highly compensated list, with total reported compensation of $1,597,747 up from about $1,412,660 last year. He earned base compensation of $389,856, and other reportable compensation of $1,207,891.

Douglas Mark

While a partner in a San Francisco marketing and design firm, for over 20 years Douglas Mark wrote online and print content for the world’s biggest brands, including United Airlines, Union Bank, Ziff Davis, Sebastiani and AT&T.

Since his first magazine article appeared in MacUser in 1995, he’s also written on finance and graduate business education in addition to mobile online devices, apps, and technology. He graduated in the top 1 percent of his class with a business administration degree from the University of Illinois and studied computer science at Stanford University.