The United States has plenty of room for more apprenticeship programs, according to a new study co-published by Harvard Business School and the labor-market analytics firm Burning Glass Technologies. While apprenticeships in the country are relatively common in 27 different occupations—mostly concentrated in construction and extraction (i.e., mining)—it is possible to develop them in nearly 50 others, the report, which was co-authored by Harvard’s Joe Fuller and Burning Glass’s Matthew Sigelman, said.

If apprenticeship programs were expanded to 74 occupations total, they conclude, people without college degrees could’ve had the opportunity to fill 3.3 million of last year’s 23.4 million job openings. Some of the jobs that could be opened up to apprentices include those as billing and shipping clerks, chefs, head cooks, and nuclear medical technologists; the average salary is about $55,000 for college graduates in those positions now, according to the study.

New companies are often discouraged by the initial costs of creating apprenticeship programs, which include those needed to set up a process for identifying and interviewing candidates, to provide the actual training, and to pay the apprentice’s salary. Many companies see these new expenditures as unnecessary fees that add on to the money they’re already spending on their full-time employees.

Fuller thinks these employers are misguided. They’re not taking into account failed hires, he argues, or employees who end up leaving because they aren’t a good fit or find a better opportunity. Apprenticeship programs could minimize the number of failed hires because an employer would have had some time to see a laborer work before extending a full-time job offer. According to Fuller, the expansion of apprenticeship opportunities could lessen employers’ total labor costs in the long-run: Apprentices’ salaries tend to be lower than that for employees with bachelor’s degrees.

According to the study, 20 percent to 80 percent of job postings ask for candidates with bachelor’s degrees, depending on the occupation, but a lot of those positions don’t actually require college experience. In other words, employers use college degrees as a proxy for a range of skills that can in fact be attained without a college degree. This practice is called degree inflation, and the result is that, depending on the occupation, “college graduates [will] find themselves recruited for jobs in which their colleagues don’t have degrees,” Fuller said, noting that those non-degreed colleagues were hired before such inflation became common practice. This educational-background difference “leads to [the college graduates having] higher turnover and [lower] job engagement than non-college graduates.”

What makes an apprentice appealing to employers is that she is likely to be just as “productive and fast as a college graduate,” Fuller said. Additionally, because apprentices have fewer overall opportunities than those with bachelor’s degrees, their turnover rate is lower. Apprentices also have lower expectations about their starting salary: Employers pay those with bachelor’s degrees 11 percent to 30 percent more than non-degree workers with experience to do the same job.