Early in the introductory college economics course, instructors talk about the Law of Diminishing Returns. An illustration: A farmer has a 100-acre field on which he wants to harvest wheat. If he does all the work himself, he can get 5,000 bushels of grain. With a second worker helping him, he can get 8,000 bushels, and with two helpers, 9,000. As more workers are added, output rises, but by sharply diminishing amounts.

Another example: The first ice cream cone a consumer eats adds a lot of pleasure (what economists call “utility”), but if the consumer is forced to eat lots of them, by the sixth or seventh cone the consumer may actually be uncomfortable from consuming too much of a good thing.

Like most things in life, higher education is subject to the Law of Diminishing Returns. Unfortunately, academics often ignore it, which leads to a massive misallocation of resources as government policy pushes us past the point of diminishing returns with college attendance.

Let’s start with the most fundamental question: How long should a student go to college in order to be certified as having “graduated,” or as having had a learning achievement justifying granting a bachelor’s degree? At America’s first university, Harvard, and nearly all others, the answer typically is four years, with a “year” in academia (unlike for the rest of humankind) defined as roughly 32 weeks of instruction. (The other 20 weeks in the calendar year were originally devoted to helping plant and harvest crops on the family farm.)

Yet at Britain’s first university, Oxford, a bachelor’s degree is typically awarded after three years of even more abbreviated (24 weeks of instruction) annual terms.

Why did it take Thomas Jefferson, a formidable intellect and prodigious bibliophile, only two years to graduate from the College of William and Mary, when our most recent presidents, with far lesser reputations for erudition, took twice as long to earn their degrees?

During a traditional liberal-arts education (which, increasingly, is being shunned in favor of more vocational-type training), students take foundational courses in their freshman and sophomore years, perhaps developing a good familiarity with literary titans and even mastering the rudiments of a foreign language or solidifying their knowledge of basic science and math. Students usually also gain at least a core understanding of the subject of their “major.” The junior and senior years are then devoted to deeper study of the major and the completion of a variety of electives.

All of that may be enlightening, but at some point, diminishing returns set in.

Using my subject of economics as an example, the critically important concepts are introduced in the first course or two: the importance of scarcity and opportunity costs, how market prices and competition help allocate resources efficiently, how and why output varies over time, and so forth. In the third and fourth year, students take specialized courses in relatively narrow areas of economics: money and banking, public finance, game theory, international trade issues, labor economics, statistics, and econometrics.

Rarely do graduating students use much of the knowledge gained in these latter classes extensively in the postgraduate world—with the exception being some students who go on to get advanced economics degrees.

On the basis of six decades of teaching, I would say that probably 60 percent of the important economic insights for the average student are learned in the first Principles of Economics survey course. The next 10 courses provide the other 40 percent. The Law of Diminishing Returns is at work here, and I think the same applies to most other academic disciplines.

Nevertheless, the cost to the student of college remains roughly the same in the senior year as it was in the first year of study. But the educational benefits sharply decline. Many students might want to leave after, say, three years, but the monetary “sheepskin effect” of having a diploma is substantial. Most employers are dazzled by the degree itself, not the student’s useful knowledge. If degree-completion were shortened to the European three-year standard, student costs would decline about 25 percent, and student borrowing to finance college would fall dramatically.

So why doesn’t it happen?

For one thing, money: Colleges want four years or even more of tuition fees per student, not just three years. For another, faculty want to teach relatively esoteric, low-demand advanced courses that seniors might feel compelled to take rather than packed courses with freshmen or sophomores.

Moreover, the colleges control the accrediting organizations that help enforce the four-year graduation standard. A school wanting to switch to a three-year degree would likely get flack from its general accreditor, which is essentially controlled by the competing schools it accredits. Accreditation reeks of monopoly elements, disastrous conflicts of interest, and other maladies that are worthy of a few essays of their own on another day. [Editor’s note: Read the Martin Center’s most recent take on the subject here.]

If colleges went to a three-year bachelor’s degree with internship/apprenticeship opportunities, students could get a good general education and solid training in a major field of study, along with practical experience in the real world of work.

Earnings data suggest that a large part of the human capital of our workers comes not through their formal study as children and young adults but via their on-the-job training. College graduates at age 50 typically make much more money (often at least double) than what their similarly trained 23-year-old counterparts make. Getting students out into the world a year or so earlier via three-year degrees would reduce education costs, increase the working proportion of the population, reduce student debt, and improve the national output. Let’s do it.

One caveat is in order. Some college education at present is effectively high-level vocational training, which may take four years to do correctly. I am thinking of degrees in engineering or architecture, for example. The optimal amount of higher education probably varies by discipline.

For students learning to do computer coding, a rigorous one- or two-year course works beautifully and avoids the unproductive diminishing returns associated with taking a plethora of largely irrelevant courses. I read stories of students who, after a couple of years of intensive training, get extremely well-paid jobs in computer-intensive fields. No extraneous coursework, no brainwashing in diversity and equity—just useful training. Such programs evidently do not go past the point of diminishing returns.

Higher education could learn from this experience. To be sure, we now offer professional degrees for those wanting to enter highly skilled vocations like medicine or law. But even here, I think reform is needed. I will save that for the second installment on this topic, coming next month.