I took an ethics class my sophomore year at the University of Arizona, and I'll never forget the very first thing my professor said, "I'm not here to be your babysitter." Unlike many of my other instructors, he refused to take attendance; and I liked this policy so much I even wrote about it for the college newspaper. 

What I failed to realize is the cost of skipping class; Forbes recently crunched the numbers, and the findings are troubling. According to College Board, the average tuition for an out-of-state student at a public institution is close to $22,958, and attending a private four-year school costs an average of $31,231. If you're taking 15 hours of courses per week during a 30-week school-year, you waste $51.02 for ditching class at a public institution and close to $70 at a private one. 

In other words, bailing on that 8 a.m. Philosophy 101 class costs as much as a decent dinner on the town for two. Many students don't see it this way however, and at times, it can cost them more than squandered money.

“I had a roommate freshman year kicked out of college for not attending enough classes," Columbia College student Caleb Hiltunen told The Wall Street Journal in January. "This kid was smart but he was lazy and had no motivation."

That's why Hiltunen agreed to participate in Class120, an app that notifies a student's parents every time that student misses class. Hiltunen told The Wall Street Journal that Class120 might have helped save his roommate who ditched one too many classes to stay in school.

Why attendance often determines grades

Many teachers factor attendance and class participation into a student's overall grade, and while this keeps students honest, some of them feel it's a silly requirement since they're the ones paying to be in class.

“As students paying to enroll in these courses, the attendance should be up to us and not roped into course grading in any way shape or form,” Sam Artley, who studied social relations and policy at Michigan State University, told USA Today in 2012. 

Academics are on the side of students though, and these policies are designed to help them succeed, interact with classmates, and engage with the course material. Going to class, after all, can really affect a student's grade, according to Marcus Crede, an Iowa State University professor of psychology who studies the impact of attendance on performance. Crede found that the correlation between attendance and grades was very high for math, science, and engineering students. 

"Students who don’t come to class do substantially worse,” Carlos Dobkin, an economics professor at the University of California-Santa Cruz and a co-author of a study on mandatory attendance, also told Forbes.

Though students who ditch small seminars miss out on a more personal learning experience, Dobkin says bigger classes with session information posted online might be less risky to skip.

"[I]n a larger lecture class where the lecture slides are on the internet and the lecture is videotaped, maybe the cost of skipping that is zero,” Dobkin said. 

Preparing for the real world

Seth Miller, a former admissions advisor at Eastern Washington University, wrote in 2011 that showing up to class is part of preparing for the real world. Skipping a lecture might lose you money and bring down your grade, but skipping work without notifying your boss could get you fired. It's important for college students to understand these consequences ahead of time.

"College is about developing a work ethic that will serve you for the rest of your life," Miller wrote. "I’m going to let you in on a little secret; most people will occasionally be bored at their job. Now if one day you felt like work was going to be boring and decided to skip it that probably wouldn’t go over very well with your boss. You have the opportunity to set habits that will stick with you for the rest of your life and the decision is yours on the habits you develop."