The very model of a modern major major

As the dep rep for the computer science department at the time, I went to any number of lunch and dinner gatherings in some or other residential college and described the wonders of concentrating in computer science. The program is still active; mail about it last week pointed to a website with useful information and helpful comments from current majors. (“Why would anyone want to date a sociology major? We are naturally empathetic, so we can give you what your friends don’t know you need.”) But Major Choices didn’t have a discernible effect on computer science; our number of concentrators continued to hover in the low 30s per year.

Something has changed in the past couple of years, and computer science has gone from well down in the pack to a scarily big department. We used to have 60 majors; now we have 165.

And that’s just majors. A lot of students seem to find our courses appealing even if they have no plans to concentrate in computer science. COS 126: General Computer Science has 458 registered, more than the traditional leader, ECO 100: Introduction to Microeconomics, which has 437. Enrollments for this semester are astoundingly high overall, with well over 1,700 in CS courses, where last spring it was a little over 1,300, and in spring 2009 about 750. We’ve more than doubled in four years.

There’s a handy rule of thumb for exponential growth patterns like this, called the Rule of 72. Divide the doubling time (say four years) into 72, and the result is the approximate rate of growth, in this case about 18 percent per year. If this continues, it will be only a few more years before everyone at Princeton is taking computer science courses every semester.

Naturally the giant increase in enrollments is causing angst within the CS department. How do we find preceptors for a class of 450? How do we grade assignments for a class that big? The administration is not going to let us hire more faculty for what might be a short-term transient — faculty slots are one of the most rigorously controlled of all resources — but something has to give. In our case, that means more lecturers and, something not often seen at Princeton, undergrad graders for the introductory courses.

Why is computer science so popular all of a sudden? Leaving aside its intrinsic interest, of which there is some, perhaps to concerned undergrads and their parents it seems like a path to a good job in uncertain economic times. The latest exit survey from Career Services suggests that a typical CS graduate has no trouble finding a job and might well pull down $100K a year. For adventurous souls, a solid computer science background might offer a chance to do something neat, like a startup. The barriers to entry for creating a new business are almost non-existent: Hardware, software and scalable infrastructure are somewhere between free and dirt cheap. All you need is a good idea and someone to implement it.

If you do have a good idea, however, it’s better to do the implementation yourself than to contract it out to a random programmer, who might well have ideas of his or her own, or the ability to adapt yours and leave you behind. You may recall the movie “The Social Network,” which describes (presumably with artistic license) the early days of Facebook. Without in any way judging whether the Winklevoss twins had a legitimate case, they might have done better if they had spent less time rowing and more time programming. If you aspire to be as successful as Mark Zuckerberg, it surely helps to have his intelligence and drive, but it’s also highly desirable to have some of his programming skill.

The University publishes enrollments in the big departments every so often, and it always says, “Undergraduate concentration patterns have remained fairly constant over the years.” That seems true enough: The top pair is usually econ and politics, with WWS, history and molecular biology not far behind. Naturally there’s more churn further down. CS wasn’t even in the top 10 in 2011-12, but if nothing else changed, we would be number three in 2012-13.

The current boom in computer science enrollments won’t last, though the long-term numbers will likely be higher than they were five years ago — computing is too central to disappear entirely. Fortunately there are all kinds of great departments. Pick a major because it’s really fun and interesting, not for its cash or its cachet. Of course, if the major happens to come with some of those extras, that’s not a bad thing either. Computer science, anyone?

Brian Kernighan GS ’69 is a computer science professor and a Forbes faculty adviser. He can be reached at bwk@cs.princeton.edu.