Bloomberg View

The basic cause of America’s student-loan crisis is no mystery: College tuition and fees continue to soar while the earnings of recent graduates remain flat. It shouldn’t be surprising that there’s also a straightforward way to lower the cost of a college degree: Reduce the amount of time it takes to earn one.

The U.S.’s four-year bachelor’s degree is based on cultural convention, not pedagogical wisdom. In most European countries, as well as India, Singapore and Australia, the majority of undergraduate programs take three years to complete. Some U.S. colleges allow enterprising students to finish their requirements early, but that option is available only to those who enter college with sufficient credits from advanced courses taken in high school — and some elite schools are trying to limit even this practice.

Defying the industry’s inertia, a small number of U.S. schools have started to experiment with offering three-year degrees. This fall, Purdue University, a public school in Indiana that enrolls 31,000 undergraduates, announced a three-year option open to all incoming students pursuing liberal arts degrees. By carrying a slightly heavier course load and taking classes in the summer, students can complete the same number of credits required for a four-year degree. The university provides dedicated advisers to help three-year students structure their schedules. And they still have time to participate in abbreviated study abroad and internship programs.

The plan’s principal beneficiaries are students, who will save $9,000 if they live in-state and $18,400 if not. Purdue officials believe the discount will stimulate demand, allowing the university to expand its student body and make up for the loss of tuition revenue. Increasing the number of students year-round also enables more efficient use of campus facilities.

It’s not likely that other institutions will soon follow Purdue’s example. With applications to the country’s top four-year schools far surpassing the number of available spots, colleges have little incentive to provide a discounted option.

But getting a college education is more than just a commercial transaction. There is a public interest in making higher education more widely available to qualified students. The role for public officials may be limited, but it can still be helpful: tying eligibility for state and federal student aid to a school’s offering of a three-year option, for example.

Not everyone needs a traditional college education. As Education Secretary Betsy DeVos said this week, the U.S. needs more pathways that allow Americans without one to reach (or remain in) the middle class. For those who want a college degree, however, obtaining one needn’t take so long. A three-year degree is a simple, cost-effective way to set more students up for future success.