For 13 years of primary and secondary schools in the United States, parents are assured of one thing: Their children will be taught by full-time teachers whose job it is to be at school for a specified time period each day classes are in session.

But when those kids go off to college, there is no such guarantee. About half of all professors at four-year colleges teach part-time as adjuncts (and the number is even higher at community colleges).

Some adjuncts are working professionals who want to teach on the side and earn a little extra cash (and I mean a little, about $2,500 per 15-week course at many colleges). Many adjuncts, however, have a Ph.D. and would like full-time academic jobs with tenure. In a bid to save money and increase their flexibility in a changing economy, colleges are hiring fewer full-time faculty and more and more adjuncts.

In Wisconsin, Gov. Scott Walker is getting plenty of attention right now for his plan to weaken faculty tenure at the state’s university system. But too often, debates about faculty tenure overshadow concerns about full-time status for professors. The two are often conflated in the eyes of the public, even though they are unrelated: Faculty members can teach and research full-time in higher education without the benefit of tenure.

Most parents and students who are shelling out an average of $31,231 in tuition and fees at a private four-year college each year and $9,131 at a public four-year university don’t often care if their kids are being taught by tenured faculty members. But they should care if those professors are on campus full-time.

While there remains a debate about whether full-time professors actually make better teachers, there is a strong correlation between student success and faculty members who stick around campus to mentor students outside the classroom. Adjuncts often need to rush off to their next gig.

For example, taking classes with full-time professors is critical during the first year of college, when it is easy to remain anonymous in large lecture halls and when students are most at risk of transferring or dropping out. Unfortunately, that’s when many colleges and universities utilize adjuncts for intro-level courses. Researchers have found that getting to know at least one faculty member well in the first year of college improves the chances that students will get more from their experience (including a degree).

Yet most first-year students rarely interact with professors, according to the National Survey of Student Engagement, an annual poll of freshmen and seniors. About two out of five freshmen say that they have “never discussed ideas from readings or classes with faculty members outside of class.” Another three out of five freshmen say they never worked with professors on activities other than coursework.

Engagement with full-time faculty members also has an outsized impact in life after college. According to the Gallup-Purdue Index — a collaboration between the polling firm and Purdue University — when graduates said they had a professor who cared about them as a person and encouraged them to follow their dreams their chances of being more engaged in life and work more than doubled.

The problem is that among the 30,000 college graduates Gallup polled, only 14 percent recalled having a professor who made them excited about learning and encouraged them.

Part-timers tell me they are usually under pressure to ease up on students as compared to full-time professors, who are more assured of returning to campus the following year. Adjuncts are mostly hired by the semester and they depend on positive student evaluations at the end of the term to get their contracts renewed. One way to ensure a good evaluation is to be an easy grader.

Stephen Hampe, an adjunct professor who has taught psychology at Utica College and several City University of New York and State University of New York campuses, told me that course evaluations now look eerily similar to customer satisfaction surveys from department stores. They ask questions such as “Did the instructor meet your needs?” and “Was the information presented in a style you found useful?” And students often include comments about how enjoyable the material was or how fun the course was, but they say little about how much they learned or the challenges of the course.

“When I was a student in the 1980s,” Hampe said, “the concern was whether the instructor served the class as a whole. Today, every student has come to expect personalized service.”

Adjuncts have their place in the academic life of an undergraduate, of course, but not in the first year or two of college. But they can be very helpful to students as they think about the transition to the workforce after college. Often adjuncts are working professionals in the career field that students want to eventually pursue and can assist in securing internships or jobs. And adjuncts who work full-time in careers outside of academia can usually give students a more realistic view of the workplace they’ll soon enter than full-time professors who are on campus all day.

The problem is that it’s very difficult to determine exactly who teaches courses — adjuncts or full-time professors — until you register for classes. The course catalogs that list all the classes offered in a major rarely, if ever, tell prospective students whether a full-time professor is teaching a class.

If you’re a high school student planning to take college tours this summer, be sure to ask what percentage of the campus faculty is full-time and what percentage of first-year classes they teach. It’s a question any college should be able to easily answer and one you deserve after 13 years of not really having to worry about whether your teacher needs to run off after class to another job.